mechatronics troubleshooting learning activity packet …€¦ · learning activity packet...

LEARNINGACTIVITYPACKET

MECHATRONICSTROUBLESHOOTING

MECHATRONICSSYSTEMSTROUBLESHOOTING(SIEMENS S7-300/STEP 7)

B25015-BA02UEN

B25015-BA02UEN MECHATRONICS SYSTEMS TROUBLESHOOTINGCopyright © 2014 Amatrol, Inc.

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LEARNING ACTIVITY PACKET 2

MECHATRONICS SYSTEMS TROUBLESHOOTING

INTRODUCTIONThis is the second of two LAPs covering Mechatronics troubleshooting. The

fi rst LAP discussed basic troubleshooting skills. This LAP discusses a systematic method for troubleshooting the entire Mechatronics system. This method combines the troubleshooting skills learned in the previous LAP with the processor troubleshooting skills covered in Segment 1 of this LAP.

Other segments will introduce PLC system troubleshooting techniques and tools and provide hands-on Mechatronics troubleshooting.

ITEMS NEEDEDAmatrol Supplied 87-FTSS7-BAX Mechatronics Troubleshooting Learning System for Siemens S7 - one per station

One or more of the following Mechatronics Stations: 87-MS1 Pick and Place Feeding Station 87-MS2 Gauging Station 87-MS3 Indexing Station 87-MS4 Sorting and Queuing Station 87-MS5 Servo Robotic Assembly Station 87-MS6 Torquing Station 87-MS7 Parts Storage StationOne of the following PLC controls per station: 870-PS7313-BAU, 870-PS7314-BAU, or 870-PS7315-BAU Mechatronics Learning System for Siemens S7-300 72024 Siemens S7-300 Programming Cable - one per station

Amatrol or School Supplied 82-900 Siemens Step 7 Programming Software - one per station

School Supplied Computer with Windows XP Windows 7 Operating System with two or more USB ports Multimeter

FIRST EDITION, LAP 2, REV. CAmatrol, AMNET, CIMSOFT, MCL, MINI-CIM, IST, ITC, VEST, and Technovate are trademarks or registered trademarks of Amatrol, Inc. All other brand and product names are trademarks or registered trademarks of their respective companies.Copyright © 2014, 2013, 2012 by AMATROL, INC.All rights Reserved. No part of this publication may be reproduced, translated, or transmitted in any form or by any means, electronic, optical, mechanical, or magnetic, including but not limited to photographing, photocopying, recording or any information storage and retrieval system, without written permission of the copyright owner.Amatrol,Inc., 2400 Centennial Blvd., Jeffersonville, IN 47130 USA, Ph 812-288-8285, FAX 812-283-1584 www.amatrol.com


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TABLE OF CONTENTS

SEGMENT 1 PROCESSOR TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4OBJECTIVE 1 Describe the function of the diagnostic buffer and give an applicationOBJECTIVE 2 Describe the operation of the diagnostic buffer

SKILL 1 View the diagnostic bufferOBJECTIVE 3 Describe how to troubleshoot an S7-300 processor that controls local I/O

SKILL 2 Troubleshoot an S7-300 processor fault that controls local I/OOBJECTIVE 4 Describe the operation of Error OBs

SKILL 3 Troubleshoot a fault using Error OBs

SEGMENT 2 PLC SYSTEM TROUBLESHOOTING TECHNIQUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43OBJECTIVE 5 Describe fi ve methods of PLC troubleshooting and give an application of eachOBJECTIVE 6 Describe four types of PLC component testsOBJECTIVE 7 Describe a six-step sequence to troubleshoot a PLC

SKILL 4 Use a six-step sequence to troubleshoot a mechatronics stationSKILL 5 Troubleshoot a mechatronics system

SEGMENT 3 PLC SOFTWARE TROUBLESHOOTING TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91OBJECTIVE 8 Describe the operation of the Search function and give an applicationOBJECTIVE 9 Describe the operation of the Go To function and give an application

SKILL 6 Use the Search and Go To functions to fi nd an instruction

SEGMENT 4 TROUBLESHOOTING MECHATRONICS STATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107OBJECTIVE 10 Describe how to use a Sequence of Operation table to troubleshoot a mechatronics process

SKILL 7 Use a Sequence of Operation table to troubleshoot a mechatronics processOBJECTIVE 11 Describe how to troubleshoot multi-station faults

SKILL 8 Troubleshoot handshaking and permissive faultsSKILL 9 Troubleshoot multi-station faults


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SEGMENT 1PROCESSOR TROUBLESHOOTING

OBJECTIVE 1 DESCRIBE THE FUNCTION OF THE DIAGNOSTIC BUFFER AND GIVE AN APPLICATION

The diagnostic buffer is an area in the processor’s memory that records status changes, or events, in the PLC system. The diagnostic buffer records two types of events:

•System Events - These events are normal occurrences, such as a processor mode change (i.e. STOP to RUN), or program download.

•Diagnostic Events - These are events that the processor interprets as an error. The events are listed in the order in which they occurred and cannot be cleared.

The buffer is often used to troubleshoot the PLC system. The contents of the diagnostic buffer are always retained, even after a memory reset. This allows the events to be viewed even if a problem causes the processor to enter STOP mode. An example of the diagnostic buffer is shown in fi gure 1.

Figure 1. Diagnostic Buffer

DIAGNOSTICBUFFER TAB


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Figure 1 shows the diagnostic buffer entry for a fault that caused the processor to enter the STOP mode. It can be seen from the entry that the fault occurred in OB1 due to a call to a data block that was not loaded into the processor. ‘

OBJECTIVE 2 DESCRIBE THE OPERATION OF THE DIAGNOSTIC BUFFER

An example view of the diagnostic buffer is shown in fi gure 2. The diagnostic buffer content is displayed in two list boxes on the dialog. The upper, or Events, list box contains a list of all the diagnostic events that have occurred.


Each event is listed with the following information:

•No. - The sequence of the entry (the newest entry is always assigned the number 1).

•Time of day - The time of the module is displayed if the module has an inte-grated clock. For the time data to be valid, it is important to set the time and date on the module and check it regularly.

•Date - The date of the event.

•Event - A short description of the event.

HELP ONEVENT

BUTTON

EVENTSLIST BOX

DETAILSON EVENTLIST# BOX


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The lower box displays additional information about the event selected in the upper box. Details include the name and number, a description and possibly the address of the command that caused the event and any mode change that may have occurred.

The Help on Event button displays even more information and possible steps to recover from the selected event.

A block diagram of the diagnostic buffer is shown in fi gure 3. The CPU detects both system events, such as a mode change from STOP to RUN, and diagnostic events, such as a programming error. System Event details are entered into the diagnostic buffer without any indication to a user or operator.

Figure 3. Diagnostic Buffer Block Diagram

A diagnostic event is generated either by the CPU or by a diagnostic interrupt sent to the CPU by an attached module with built-in diagnostic capability, such as an input/output module or communications processor. The CPU evaluates the error, makes an entry in the diagnostic buffer, and lights the SF LED on the processor to indicate that an error has occurred. The CPU may then attempt to call an error OB, or stop the processor if an error OB has not been loaded into the processor.

SYSTEMEVENT

DIAGNOSTICEVENT

DIAGNOSTICBUFFER

CPU

DIAGNOSTICINTERRUPT

MODULE WITH BUILT-INDIAGNOSTIC CAPABILITY


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SKILL 1 VIEW THE DIAGNOSTIC BUFFER

Procedure Overview

In this procedure, you will use the SIMATIC Manager to view the contents of the processor diagnostic buffer and to interpret the contents. This will familiarize you with the types of information available in the diagnostic buffer when troubleshooting PLC faults.

1. Locate a mechatronics station. 2. Verify that this station has been separated from any other stations. If it has

not, separate it from the other stations. 3. Perform the following safety check before you begin working on the station.

Make sure that you can answer yes to each item before proceeding.

YES/NO SAFETY CHECKOUT

Remove all obstructions from the work area

Check for signs of damage to the equipment

Wear tight fi tting clothing, roll up long sleeves, remove ties, scarves, jewelry, etc.

Tie up long hair

Remove any robot teach pendants from the work area

Locate the emergency stop button

Ensure that safety glasses are worn by people in area

Ensure that all people are outside any work envelopes

Figure 4. Mechatronics Safety Check


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4. Connect an air supply to the air manifold’s quick connect in the back of the station, as shown in fi gure 5.

Figure 5. Station Air Hose Attached to Compressed Air Supply

STATIONAIR

HOSE

COMPRESSEDAIR SUPPLY


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5. Plug the station’s electrical cord into a power outlet. If the power cord is not attached to the station, locate it in the back of the station and plug the female end into the station’s power plug under the work surface at the back of the station, as shown in fi gure 6. Then plug the other end into the wall outlet.

There will be no visual indication that power has been applied to the station. Plugging the power cord into the outlet brings power to the back of the station.

Figure 6. Station Power Cord Attached to Wall Outlet

6. Place the CYCLE SELECT switch in the MANUAL position.

Figure 7. Mode Selector Switch Set to Manual Mode

STATIONPOWERCORD

STATION’SPOWERPLUG


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7. Remove the lockout/tagout device from the electrical power source. 8. Remove the lockout/tagout device from the pneumatic power source. 9. Turn on the air to the station by shifting the lever on the lockout valve. 10. Perform the following substeps to download a program to the mechatronics

station and observe the station indicators. For familiarization and troubleshooting purposes, you will use existing PLC

projects written for each mechatronics station. Use the table in fi gure 8 to select the program for your station.

STATION PROJECT

87-MS1 Feeder

87-MS2 Gauging

87-MS3 Indexing

87-MS4 Sorting and Queuing

87-MS5 Servo Robotic Assembly

87-MS6 Torquing

87-MS7 Parts Storage

Figure 8. Mechatronics Station Projects

A. Make sure the PC adapter cable is connected between the PC and the PLC.

B. Start and log in to the PC.

C. Start the SIMATIC Manager.

D. Open the proper program for your mechatronics station.

E. Download the program to the PLC.


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11. Perform the following substeps to go online with the processor.

Figure 9. SIMATIC Manager

A. Click the Display Accessible Nodes button shown in fi gure 9.

Clicking this button should open a window, shown in fi gure 10, which displays the nodes that are able to communicate with the PC.

Figure 10. Display Accessible Nodes Window

DISPLAYACCESSIBLE

NODESBUTTON

PLC MENU MPI = 2 ICON


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The MPI=1 icon should only appear if an HMI terminal is connected to the processor.

B. Click the MPI=2 (directly) icon in the right-hand side project window to select it.

It should highlight in blue to indicate it is selected.

C. Select the PLC menu.

D. Select the Diagnostic Setting option from the PLC menu.

A submenu should appear for the Diagnostic Setting option.

E. Select the Module Information option from the submenu.

A Module Information dialog similar to the one shown in fi gure 11 should appear.

The General tab should be selected on the dialog.

Figure 11. Module Information Dialog


GENERALTAB


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F. Click the Diagnostic Buffer tab on the dialog to view the processor’s diagnostic buffer, shown in fi gure 12.

Figure 12. Diagnostic BufferHELP ON EVENT

BUTTON

CLOSEBUTTON

EVENT NO. 1


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G. Select the top event in the Events section (Event No. 1) by clicking it.

Event No. 1 should be a transition from Startup to Run.

Not all of the events listed in fi gure 12 will match the events listed on your screen.

Notice the Details on Event window toward the bottom of the dialog. This area contains a detailed listing of the selected event. The scrollbar at the right of the Details on Event window can be used to view the entire contents of the window.

The exact wording in the Details on Event window depends on which version of STEP 7 you are using and events recorded earlier.

The Details on Event window lists:

Mode Transition from STARTUP to RUN

Startup information:

- Time for time stamp at the last non-backed up power on

- Single processor operation

Current/last startup type:

- Warm restart triggered by switch setting

Permissibility of certain startup types:

- Manual warm restart permitted

- Automatic warm restart permitted

Last valid operation of setting of automatic startup type at power on:

- Warm restart triggered by switch setting

Previous operating mode: STARTUP (warm restart)

Requested operating mode: RUN

Incoming Event

The actual contents listed may differ depending on the type of processor used.

H. Click the Help on Event button to display the help screen that is available for the selected event.

Every entry in the Events section has an associated Help screen that provides information about the selected events.

I. Close the Help on Event window by clicking the [X] in the top right-hand corner of the window.

J. Click the Close button shown in fi gure 12 to close the diagnostic buffer. 12. Perform the following substeps to power down the PLC trainer.

A. Close the SIMATIC Manager.

B. Turn off the PC and monitor.

C. Power down the mechatronics station.


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OBJECTIVE 3 DESCRIBE HOW TO TROUBLESHOOT AN S7-300 PROCESSOR THAT CONTROLS LOCAL I/O

The confi guration used by the processor determines how to troubleshoot it. A PLC processor module can be set up in one of three operational confi gurations:

•Local I/O - The processor controls I/O located only in its own rack.

•Expansion I/O - The processor controls I/O in up to three racks, in addition to its own rack. The racks are connected using interface modules.

•Distributed I/O - The processor exchanges data with other processors over a network, including control of other processor’s I/O. For S7-300 PLCs, this network is either MPI or Profi bus-DP.

The confi guration used in this objective is one in which the processor is only controlling local I/O and not connected to a network.

The steps required to troubleshoot an S7-300 processor that controls local I/O are:

Step1: Check the processor’s fault indicators.

Step2: Check the diagnostic buffer to determine the type and location of the fault.

Step3: Correct the problem.

Step4: Return the processor to RUN mode and check the SF indicator.

Step 1: Check the Processor’s Fault Indicators

Troubleshooting a processor fault begins with the processor’s fault indica-tors. When the processor is running correctly, the fault indicators should be off. If something causes the processor to stop running, the indicators will turn on. The type of fault encountered determines which processor fault LED turns on, either SF (System Fault) or BF (Bus Fault). Figures 13 and 14 show a fl owchart for troubleshooting the processor. The details of these fl owcharts are in the following paragraphs.


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Figure 13. Processor Troubleshooting Flow Chart, Sheet 1

THE POWER INDICATOR IS ONAND THE SF INDICATOR IS STEADY RED

CHECK PROCESSORDIAGNOSTIC BUFFER TODETERMINE FAULT TYPE

AND LOCATION

CORRECTPROGRAM

ERROR

DOWNLOADPROGRAM

PLACE PLCIN

RUN MODE

CHECK FAULTINDICATOR

DONE

Off

CONSULTFACTORYRed

PROGRAMMINGERROR

Yes

TROUBLESHOOTNON-PROGRAMMING ERROR FAULTNo

Go toSheet 2


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Figure 14. Processor Troubleshooting Flow Chart, Sheet 2

• RESET MEMORY• DOWNLOAD

PROGRAM

DOES PROCESSOR HAVEA MEMORY MODULE?

CYCLE PLC TO STOPAND THEN BACK

TO RUN

CHECK SFINDICATOR,IS IT OFF?

CHECK INSTALLATIONOF

MEMORY MODULE ORMMC CARD

TURN ON POWER

• SET PLC TO STOPMODE

• RESET MEMORY

CHECK FAULTINDICATOR STATUS

RESTORE PROGRAMAND RETURNTO RUN MODE Off

REPLACEPROCESSOR

Red

Yes

No

Yes

No

ENTER FROM PROCESSOR TROUBLESHOOTINGFLOW CHART SHEET 1 (FIGURE 8):

SF INDICATOR IS STEADY RED

YOU ARE DONETROUBLESHOOTING

TURN OFFPOWER


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SF Red Condition

This indicates that a system fault has occurred. The fault can be caused by a program instruction that the processor is unable to execute, a fault in a connected module that has diagnostic capabilities, or other hardware problems. The processor will attempt to call the error OB for the type of problem that has been detected. If the error OB is not present, the processor will place itself into STOP mode.

BF Red Condition

A red BF indicator means that an error has been detected on the processor’s Profi bus-DP interface. Errors of this type will be covered later.

Step 2: Check the diagnostic buffer to determine the type and location of the fault

The diagnostic buffer can be used to view the details of the event that caused the fault. A view of a diagnostic buffer entry that caused the processor to enter the STOP mode is shown in fi gure 15.

Notice that the stop was caused by a programming error. Notice Event 2 states that a DB or data block was not loaded. Event No. 2 is the actual error, and Event No. 1 is the reaction to the error.




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Step 3: Correct the problem

Depending on the type of problem, this may involve replacing hardware or correcting a programming error and downloading the corrected program to the processor. For the problem shown in fi gure 10, the missing DB would have to be located and downloaded to the processor, or the call to the missing data block removed from the program.

Step 4: Return the processor to RUN mode and check the SF indicator

If the SF indicator is off, the problem has been corrected. If it is still on, the problem is beyond the scope of normal troubleshooting procedures, call factory support.


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SKILL 2 TROUBLESHOOT AN S7-300 PROCESSOR FAULT THAT CONTROLS LOCAL I/O

Procedure Overview

In this procedure, you will troubleshoot a common processor fault using the SIMATIC Manager. This will familiarize you with the processor’s diagnostic buffer and with troubleshooting processor faults.

1. Perform the following substeps to prepare a mechatronics station.

A. Obtain a mechatronics station and set it up for single station operation. Make sure any fi xtures or bins are installed for single station operation.

B. Verify that a USB cable connects the 87-FTS fault box to the PC. 2. Perform the following safety check before you begin working on the station.






Tie up long hair






3. Perform the following substeps to power up the station.

A. Place the CYCLE SELECT switch in the MANUAL position.

B. Turn the station’s ON/OFF switch to the ON position.

C. Turn on the PC and monitor and log in to windows.


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4. Perform the following substeps to delete the blocks currently in the processor. This skill requires that no blocks are in the processor before the project is

downloaded. Any blocks left in the processor can cause unintended operation.

A. Verify that the PC adapter cable is connected between the PC and the PLC.

B. Open the SIMATIC Manager.

C. Click the Accessible Nodes button, shown in fi gure 21, on the SIMATIC Manager’s toolbar.

The Accessible Nodes window should open.

D. Double-click the MPI=2 folder to open it.

A Blocks folder should be displayed.

E. Double-click the Blocks folder to open it. All blocks in the PLC memory should be displayed as shown in fi gure 17.

Figure 17. Accessible Nodes Button on Window

F. Click on block OBI to highlight.

G. Select Delete from the SIMATIC Manager’s Edit menu.

A dialog should appear to warn you that the procedure cannot be undone.

H. Click Yes on the dialog.

The block should be removed from the display.

BLOCKSFOLDER

MPI=2FOLDER

ACCESSIBLENODES BUTTON OB1

PLCBLOCKS


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I. Delete all OB and DB blocks using the same procedure.

J. Close the Accessible Nodes window by clicking the [X] in the right-hand corner of the window.

5. Perform the following substeps to download block OB1 to the processor.

A. Click the Open Project/Library button on the toolbar.

The Open Project/Library dialog should open.

B. Locate project Mech_Trouble.

The project Mech_Trouble was provided on a supplemental disk.

If it is not listed on the dialog, click the Browse button on the dialog to view the projects located in the S7Proj folder. (A project will not be listed on the dialog until it has been opened using the SIMATIC Manger).

C. Double-click the Mech_Trouble folder to open the project.

D. Select Expand All or Show All Levels from the View menu to expand the contents of the project.

E. Click the Blocks folder object to select it.

The Blocks folder should contain several objects: a System Data folder that contains the hardware confi guration, OB1, DB1, and OB121.

F. Select OB1 by clicking it.

G. Click the Download button on the toolbar to download OB1 to the processor.

The other blocks will be used later.

You should notice that the PLC places itself in STOP mode. The SF indi-cator should turn red, indicating a system fault.

6. Examine the status of the PLC’s status indicators and record your observations in the table shown in fi gure 18.

An S7-315 processor may have BF1, BF2, and MAINT indicators in addition to the indicators used on the S7-313 and S7-314.

MODULE INDICATOR STATUS

Processor

SF

BF, or BF1 and BF2

DC5V

FRCE

RUN

STOP

MAINT

Figure 18. PLC Status Indicators

You should observe that the CPU placed itself into the STOP mode. The STOP indicator and SF indicator should both be illuminated red and the STOP indicator solid amber. The DC5V indicator should be illuminated green and the RUN, FRCE, MAINT, and BF (BF or BF1 and BF2) indicators should be extinguished.


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7. Perform the following substeps to view the processor’s diagnostic buffer.

A. Select the PLC menu.

B. Select the Diagnostic Setting option from the PLC menu.

A submenu should appear for the Diagnostic Setting option.

C. Select the Module Information option from the submenu.

The Module Information dialog shown in fi gure 19 should appear.




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D. Click the Diagnostic Buffer tab to view the contents of the processor’s diagnostic buffer, as shown in fi gure 20.


Notice that Event No. 1 is selected. Look at the Details on Event window. It lists “Stop caused by programming error (OB not loaded, or no FRB).” The fi rst event is not the error, it is the reaction to the error. When the error was encountered, the processor placed itself into the STOP mode.

OPEN BLOCKBUTTON

DETAILS ONEVENT LIST BOX


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E. Select Event No. 2 by clicking it.

The screen should appear similar to that shown in fi gure 21.


Notice that the Details on Event window indicates “DB not loaded.” This means a call was made to a data block that didn’t exist in the processor. The next line lists the DB number as 1. This means the program tried to call DB1, which wasn’t loaded into the processor. It then lists “Requested OB: Programming Error OB (OB121), OB not found, or disabled, or cannot be started in the current operating mode.” When the processor encounters certain kinds of errors, an error OB is called. In this case, it called OB121. When it was not found, the processor placed itself into the STOP mode.

F. Select Event No. 1 by clicking it.

Notice that the Open Block button has activated.

DB NOTLOADED


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G. Click the Open Block button.

Clicking this button will open an online view of the block where the problem occurred.

The dialog shown in fi gure 22 may appear. If so, click Online to continue.

Figure 22. Off/Online Prompt

OB1 should open as shown in fi gure 23.

Notice that Network 2 is selected. The network unconditionally calls DB1. This is where the processor encountered problems, because DB1 was called, but not loaded.

Figure 23. OB1 Networks

PLC MENU


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8. Perform the following substeps to attempt to restart the processor.

A. Select Operating Mode from the LAD/STL/FBD Editor’s PLC menu.

The Operating Mode dialog should open.

B. Click the Warm Restart button to attempt to restart the processor.

The dialog shown in fi gure 24 should open.

Figure 24. Operating Mode Dialog

C. Click Yes on the dialog to restart the processor.

Watch the processor’s indicators.

Notice that a restart is attempted, but that the processor stays in the STOP mode.

Restarting the processor starts program operation. The program tries to call DB1, which shuts down the processor. The only way to restart the processor is to fi x the problem.

D. Click the Close button to close the Operating Mode dialog. 9. Close the online LAD/STL/FBD Editor by clicking the large X in the top

right-hand corner.


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10. Display the Module Information dialog by selecting it from the PC’s taskbar. Make sure the Diagnostic Buffer tab is still selected. It should appear similar to that shown in fi gure 25.


Notice in the Events window that there are now two instances of “DB not loaded” and “Stop caused by programming error (OB not loaded or not possible, or no FRB).” There is also a request for warm restart listed in event 4. This shows that the restart was requested, but the processor faulted immediately when trying to open DB1.

11. Close the Module Information dialog by clicking the Close button on the dialog.

12. Perform the following substeps to download DB1 to the processor.

A. Display the SIMATIC Manager by selecting it from the PC’s taskbar.

B. Select the Blocks folder by clicking it.

C. Click the DB1 object to select it.

D. Click the Download button on the toolbar.

DB1 should download to the processor.

E. Open the PLC menu by clicking it.

F. Select the Diagnostic/Setting option.

G. Select the Operating Mode option.

The Operating Mode dialog should appear.

SECONDINSTANCE

FIRSTINSTANCE


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H. Click Warm Restart on the Operating Mode dialog to restart the processor.

The processor should restart since DB1 is now in the processor’s memory.

I. Close the Operating Mode dialog.

You have now seen how the diagnostic buffer can be used to interpret the cause of a processor fault.

13. Perform the following substeps to remove the downloaded blocks from the processor.

Blocks can only be removed by going online and deleting the blocks.


B. Click the Online button, shown in fi gure 26, to display the blocks loaded into the processor.

An online project window should open, as shown in fi gure 26.

Figure 26. Online Project Window

C. Fully expand the project tree.

D. Select the Blocks folder.

E. Delete blocks OB1 and DB1

A dialog should appear stating that the procedure cannot be undone.

F. Click OK on the dialog to remove the blocks from the processor.

ONLINEBUTTON


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G. Close the online project window by clicking the X in the top right-hand corner.

14. Perform the following substeps to power down the PLC trainer.

A. Close the LAD/STL/FBD Program Editor if it is open.

B. Close the SIMATIC Manager.

C. Turn off the PC and monitor.

D. Power down the Mechatronics station.

OBJECTIVE 4 DESCRIBE THE OPERATION OF ERROR OBs

In normal operation, an S7-300 processor places itself into STOP mode when an error is encountered. To prevent entering STOP mode, error OBs can be down-loaded to the processor that keeps the processor in RUN mode when errors are encountered. No programming is required in the error OB to prevent the processor from entering STOP mode. If an error OB is programmed, it is usually programmed to interpret error codes and display specifi c information about the fault in the diag-nostic buffer on the programming terminal or on an HMI panel. S7-300 processors recognize two types of errors:

•Synchronous errors - Synchronous errors are faults that occur when the processor tries to execute an instruction. For example, an instruction that tries to access an invalid memory location.

•Asynchronous errors - Asynchronous errors are caused by events outside of the program. These are faults in the subsystems (i.e. a defective processor or input module with built-in diagnostic capability). If the corresponding asyn-chronous error OB is not loaded, the CPU changes to STOP mode.

When synchronous or asynchronous errors are encountered, the processor writes error information to the diagnostic buffer, lights the SF indicator, and places itself into STOP mode. If the error OB for the fault is loaded into the CPU, the processor writes the error information to the diagnostic buffer, lights the SF indi-cator, but remains in RUN mode.

The error OBs are listed in the table shown in fi gure 27.


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ERROR ORGANIZATIONAL BLOCKS

Asynchronous Error Synchronous Errors

OB70 I/O Redundancy Error (only applies to redundant or H CPUs) OB121 Programming Error (i.e. Block or Data Block

is called but not present in the processor)

OB72 CPU Redundancy Error (only applies to redundant or H CPUs) OB122 I/O Access Error (i.e. the program tries to

access a signal module that does not exist)

OB80 Time Error (i.e. scan cycle time exceeded)

OB81 Power Supply Error (i.e. 24VDC power supply error is detected)

OB82 Diagnostic Interrupt (i.e. a short circuit is detected in a diagnostic-capable input or output module)

OB83 Remove/Insert Interrupt (Applies only to S7-400 systems) (i.e. a confi gured module is removed from the rail)

OB84

CPU Hardware Fault (i.e. an error is detected on the MPI network, the communication bus, or the network card for the distributed I/Os)

OB85

Program Sequence Error (i.e. An error occurs accessing a data block assigned to a System Function Block (SFB), or an error occurs updating the process image table (the accessed module does not exist or is defective)

OB86

Rack Failure (i.e. a missing or defective Interface Module or break on the connecting cable, a distributed power failure on a rack, or failure of a Profi bus-DP slave)

OB87 Communication Error (i.e. an incorrect message frame ID is detected)

Figure 27. Error Organizational Boxes


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For example, if a program tries to access an invalid memory area, the processor lights the SF indicator and places itself into the STOP mode. The diagnostic buffer entry for the fault is shown in fi gure 28.

Figure 28. Diagnostic Buffer with no Error OB


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If error OB122, the I/O access error OB, is downloaded to the processor, the SF indicator illuminates when the processor tries to read or write to the invalid memory error, but it remains in RUN mode. The SF indicator goes off if the program stops trying to access the invalid memory area (i.e. a pushbutton caused a network to access the area, but it is no longer pressed). The processor continues to run the loaded program. Figure 29 shows the diagnostic buffer for the fault when OB122 has been loaded into the processor.

Figure 29. Diagnostic Buffer Entry with OB122 Loaded into the Processor


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SKILL 3 TROUBLESHOOT A FAULT USING ERROR OBs

Procedure Overview

In this procedure, you will download a program to the processor that has an I/O access error fault programmed into it. You will observe the error, and then use an error OB to prevent the processor from entering the STOP mode when the error is encountered. It is important to be able to prevent the processor from stopping to either troubleshoot, or prevent the production line from shutting down. This will familiarize you with the error OBs, and with using the diagnostic buffer to evaluate the cause of faults.

1. Perform the following substeps to prepare a mechatronics station.

A. Obtain a mechatronics station and set it up for single station operation. Make sure any fi xtures or bins are installed for single station operation.

B. Verify that a USB cable connects the fault box to the PC.

C. Verify that a PC adapter cable connects the PLC to the PC. 2. Perform the following safety check before you begin working on the station.






Tie up long hair







35



B. Remove the lockout/tagout device from the electrical power source.

C. Remove the lockout/tagout device from the pneumatic power source.

D. Turn on the air to the station by shifting the lever on the lockout valve.

E. Set the station’s air supply regulator to 50 psi/345 kPa.

F. Turn the station’s ON/OFF switch to the ON position. 4. Turn on the PC and monitor and log in to windows. 5. Perform the following substeps to download project Mech_Error to the

processor.

A. Start the SIMATIC Manager.

B. Click the Open Project/Library button on the toolbar.

The Open Project/Library dialog should open.

C. Locate project Mech_Error.

Project Mech_Error was provided on a supplemental disk.

D. Double-click the Mech_Error icon to open the project and close the dialog.

E. Fully expand the project tree by selecting Expand All or Show All Levels from the View menu.

F. Select the Blocks folder by clicking it.

There should be several objects present: OB1, OB122, and the System Data folder.

G. Select OB1.

H. Click the Download button on the toolbar.

OB1 should download to the processor.

I. Open the PLC menu, point to Diagnostic/Setting, and select the Operating Mode option.

J. Click the Warm Restart button to restart the processor.

K. Click Yes on the window that opens to restart the processor. 6. Press and release the START pushbutton. The processor should light the SF indicator and enter the STOP mode. Pressing PB1 caused OB1 to try to access a memory location that is not valid

for the processor.


36

7. Perform the following substeps to open and view the diagnostic buffer.

A. Open the PLC menu, point to Diagnostic/Setting, and select the Module Information option from the SIMATIC Manager’s menubar.

The Module Information dialog can also be opened from inside the LAD/STL/FBD Editor if it is open.

The Module Information dialog shown in fi gure 31 should appear.

Notice that the dialog indicates that the processor is in the STOP mode and that the SF LED is on.


DIAGNOSTICBUFFER

MODEINDICATOR


37

B. Click the Diagnostic Buffer tab on the dialog to view the diagnostic buffer.

The diagnostic buffer should appear similar to that shown in fi gure 32.

Notice that the stop was caused by an I/O access error.


C. Select Event No. 2.

Notice that the processor attempted to call OB122 when the I/O access error was encountered. Since OB122 was not loaded, the processor placed itself in the STOP mode.

CAUSE OFSTOP


38

8. Perform the following substeps to download error OB122 to the processor.


B. Click the Blocks folder to select it.

C. Select OB122 by clicking it.

D. Click the Download button on the SIMATIC Manager’s toolbar to down-load the block to the processor.

E. Open the PLC menu, point to Diagnostic/Setting, and select the Oper-ating Mode option.

The Operating Mode dialog should appear.

F. Click the Warm Restart button to restart the processor.

The dialog shown in fi gure 33 should open.

Figure 33. Operating Mode Dialog

G. Click Yes on the dialog to restart the processor.

The processor should restart and the RUN indicator should turn on. The dialog shown in fi gure 33 should close.

H. Press and release the START pushbutton to fault the processor.

Pressing the START pushbutton causes OB1 to access an invalid memory location. The SF indicator should turn on, indicating there is still an error in the system, but the system should stay in the RUN mode because the error OB is available to the processor.

Eventually, the SF indicator will extinguish because the processor is no longer requesting the memory access (PB1 is not pressed).

This demonstrates that the error OB can be used to prevent a temporary error (requesting an invalid address) from shutting down the processor.

I. Click the Close button on the Operating Mode dialog to close it.

The Operating Mode dialog should close.


39

J. Display the Module Information dialog by selecting it from the PC’s taskbar.

K. Click the Diagnostic Buffer tab to view the contents of the processor’s diagnostic buffer.

The diagnostic buffer should appear similar to that shown in fi gure 34.

Notice that “I/O access error, reading” is the cause of all of the events listed.

Notice the times associated with each event. Each event is only a couple of milliseconds newer than the previous event. The processor tries to read and write to a bad memory location every cycle and encounters an error. It looks for OB122 every cycle, and since it is present, it remains in RUN mode.


Notice in the Details on Event window that OB122 was requested when the error was encountered.

L. Click the Close button to close the dialog.

You have now seen how a processor can be prevented from entering the Stop mode when an error is encountered.


40

9. Perform the following substeps to remove OB122 from the processor.


Your screen should appear similar to that shown in fi gure 35.

Figure 35. SIMATIC Manager


41

B. Click the Online button shown in fi gure 36 to display the blocks loaded into the processor.

An online project window similar to the one shown in fi gure 36 should open.

Figure 36. Online Project Window

C. Click the OB122 icon so that it is highlighted.

D. Select Delete from the Edit menu.

A dialog should appear stating that the procedure cannot be undone.

E. Click Yes on the dialog to remove OB122 from the processor.

F. Close the online project window by clicking the X in the top right-hand corner.

G. Press PB1 momentarily.

The processor should fault, light the SF indicator, and enter Stop mode. This verifi es that OB122 was removed from the processor.

10. Perform the following substeps to power down the mechatronics station.

A. Close the SIMATIC Manager.

B. Turn off the PC and monitor.

C. Power down the mechatronics station.

ONLINEBUTTON


42

SEGMENT 1 SELF REVIEW

1. The ____________ is an area in the processor’s memory that records status changes, or events, in the PLC system.

2. The contents of the diagnostic buffer are always _________, even after a memory reset.

3. The CPU detects both ______ events, such as a mode change from STOP to RUN, and ______ events, such as a programming error.

4. A(n) ____________ is generated either by the CPU, or by a diagnostic interrupt sent to the CPU by an attached module with built-in diagnostic capability, such as an input/output module, or communications processor.

5. The CPU evaluates the error, makes an entry in the diagnostic buffer, and lights the ____________ on the processor to indicate that an error has occurred.

6. The CPU may then attempt to call an error OB or stop the processor if an error OB has not been ______ into the processor.

7. Troubleshooting a processor fault begins with the processor’s ___________.

8. When the processor is running correctly, the fault indicators should be ______.

9. No ______ is required in the error OB to prevent the processor from entering STOP mode.

10. If error OB122, the I/O access error OB, is downloaded to the processor, the SF indicator illuminates when the processor tries to read or write to the invalid memory error, but it remains in ______ mode.


43

SEGMENT 2PLC SYSTEM TROUBLESHOOTING TECHNIQUES

OBJECTIVE 5 DESCRIBE FIVE METHODS OF PLC TROUBLESHOOTINGAND GIVE AN APPLICATION OF EACH

PLC troubleshooters should use a methodical approach to isolate the cause of a problem. The following list shows fi ve of the most common methods of trouble-shooting PLC systems. The particular method used depends on the type of system and the type of problem. It is possible to use any or all of these methods in a troubleshooting situation. The methods are:

• Symptom and Cause Method• Output-Back Method• Half-Split Method• Shotgun Method• Flowchart Method

Symptom and Cause Method

In this method of troubleshooting, the troubleshooter isolates the problem in a system according to whether or not the component could cause the symptoms observed. By fi rst testing only the areas most likely to cause the known symptom, a troubleshooter often reduces repair time.

This method is very fast if a symptom has only a few causes or has been seen before. This is why it is good to observe the machine’s operation carefully before trying to isolate the problem.

PLC diagnostic and status indicators are great tools for symptom-cause trou-bleshooting because they display the status of the system in one place.


44

Output-Back Method

In this method of troubleshooting, the troubleshooter starts testing the outputs of a system and systematically works back toward the inputs of the system until the cause of the problem is isolated. The output-back method of troubleshooting is very effective for troubleshooting PLCs because they tend to use a lot of relay instructions. Relays can cause malfunctions from an input device on a network to affect outputs on other networks.

For example, if output Q12.2 in fi gure 37 is not turning on, it could be caused by a failed LS2 limit switch. Troubleshooting would start with the output on Network 4, and work backwards through the I/Os.

Figure 37. Out-Back Method

SOL 1ADRILL EXT

SOL 2BCLAMP RET

SOL 2ACLAMP EXT

I0.0

I8.2

I8.0

M0.0

Q12.2

M0.0

I8.3

I8.2 I8.3

Q12.1

M0.0

I8.0

I8.1

I8.2

I8.3

I0.0START

DRILLEXT'D

DRILLRET'D

CLAMPEXT'D

CLAMPRET'D

Q12.1

Q12.0

M0.0

Q12.2

PB1

LS2

LS1

LS3

LS4

Q12.0

Q12.1

Q12.2

TROUBLESHOOTINGSEQUENCE

STARTHERE

OUTPUTOFF

INPUTFALSE

FAILEDSWITCH

NETWORK 1

NETWORK 2

NETWORK 4

NETWORK 3


45

Half-Split Method

This method of troubleshooting assumes that measurements before the cause of a problem will be normal and measurements after the cause of the problem will not be normal. The troubleshooter continually tests at a point half way between a known good test point and a known bad test point until the problem is isolated.

This method can be used to troubleshoot a PLC system to determine if the problem is in the power or control side.

Figure 38. Half-Split Method

POWERHALF

CONTROLHALF

I0.1 I0.0 I8.0I8.1

Q12.0I0.1

I8.1

I8.0

I0.0START

STOP

RET'D

EXT'D

Q12.0

INPUTS PLC PROGRAM OUTPUTS

PB1

PB2

LS1

LS2

SOL 1A

LS2LS1

SOL 1A

EXTEND

Q12.0

NETWORK 1


46

For example, to troubleshoot the system in fi gure 38, the troubleshooter would begin measuring for control voltage at the line side of the input devices. Once it has been determined that control power is present, measurements are made at the PLC input terminals for the Stop and Start pushbutton switches and LS1 to verify that they are closed.

If the pushbuttons and limit switch are closed, the troubleshooter measures the voltage at the input terminal for LS2 to verify that it is open. If all input conditions are met, measuring the PLC output voltage will isolate the failure to the PLC or the fi eld devices.

Monitoring the inputs online with a programming terminal minimizes the number of measurements needed to determine if the problem is in the control half or power half of the system. For example, if all of the inputs and the coil show true conditions, only the output voltage to the solenoid needs to be measured to isolate the problem to the output module or the fi eld devices.

Manually actuating the solenoid will quickly determine if the air supply is present, the solenoid is not jammed, and if the cylinder is not damaged.

Shotgun Method

This method of troubleshooting tests every component or connection in a suspect area. The shotgun method can save time if there are only a few components to test or the problem is intermittent. However, it is usually the worst method to use and will be the slowest if the circuit has several components.


47

Flowchart Method

A fl owchart, shown in fi gure 39, is a graphical method of troubleshooting which uses block symbols connected by fl ow lines to show the sequence of trou-bleshooting steps to follow. With a fl owchart, the troubleshooter starts with the block at the top. Each block instructs the troubleshooter to perform a test. From the results of each test, the chart either tells the troubleshooter the problem has been found, or it instructs the troubleshooter to proceed to another block.

A fl owchart is often used as a master troubleshooting guide for PLCs. This course uses a multi-page troubleshooting fl owchart.

Figure 39. PLC Troubleshooting Flowchart (Partial)

OUTPUT MODULE STATUS INDICATOR IS OFF

• TURN OFF POWER• RESEAT OUTPUT

MODULE• TURN ON POWER• RETURN PLC TO RUN

MODE

IS PROCESSORIN RUN MODE?

RETURN PROCESSORTO RUN MODE

CHECK STATUSINDICATOR ON

OUTPUT MODULE

CHECK STATUSINDICATOR ON

OUTPUT MODULE

REPLACE OUTPUTMODULE

YOU ARE DONEOn

Off

Off

No

On

DONE

Yes


48

OBJECTIVE 6 DESCRIBE FOUR TYPES OF PLC COMPONENT TESTS

Previously presented were fi ve methods a troubleshooter can use to trouble-shoot a PLC system. How to actually test the circuit components during the trou-bleshooting process was not discussed. The following list shows four types of PLC component tests used to test a component. Any or all of these tests may be used in a single troubleshooting situation.

•Five senses - One way of locating a component failure is with the fi ve senses. Many times, defective components will produce physical evidence of their failure. Shorted components can overheat and produce smoke or have a burned appearance. A mechanical device, such as a motor or solenoid, may make an unusual noise when it fails. It is always good to visually inspect a system fi rst.

•Measurements - The most common method of isolating circuit and compo-nent problems is to take voltage, current, and resistance measurements. This is the method used to test PLC input and output devices.

•Substitution - If a replacement part is readily available, it is common to substitute a known good part for a suspected bad one. Sometimes this is faster than taking measurements or analyzing the circuit. It is important to have spare modules for the PLC on hand. Part substitution does pose a potential for damaging a new part. For example, simply replacing a blown fuse without fi rst taking measurements often results in the new fuse failing when power is applied. However, other components, such as a sticky or jammed solenoid valve, fail because of wear and pose little threat to the substituted component.

•Component/circuit elimination - If a troubleshooter suspects that a circuit or component is providing an improper path for current, disconnecting the circuit may change the symptoms in a manner that will lead to the problem. For example, a component or circuit may connect the system to ground at the wrong point and cause shorts to occur. By disconnecting this short, the test of the system should operate again. This is a technique used to test the DC power supply.


49

OBJECTIVE 7 DESCRIBE A SIX-STEP SEQUENCE TO TROUBLESHOOT A PLC

Effective troubleshooting always includes a well-organized approach to solving a problem. The following is a six-step process for troubleshooting and repairing a PLC system:

Step 1: Identify the Problem or Symptom

Step 2: Check the Status Indicators

Step 3: Troubleshoot the PLC Subsystem

Step 4: Test the Suspected Component

Step 5: Repair or Replace the Suspected Component

Step 6: Test the Repaired System

Step 1: Identify the Problem or Symptom

Always identify the details of the problem in the system before trying to solve it. Careful observation of the machine will provide many clues to what might be wrong. Also talk to the operator to fi nd out what happened when the failure occurred.

The problem should be described in terms of what the machine or system is not doing correctly ( e.g. the mold does not open) and in terms of the specifi c output devices (e.g. cylinder 2 does not retract). It is also a good idea to observe the machine’s operating conditions, such as air temperature, machine speed, and time of day. These conditions will often provide clues about the source of the problem.

Problems can fall into several types. The most common type is an output device, such as an actuator, which does not turn on or off when it is supposed to. This can cause the machine to either stop in the middle of the sequence, turn on an actuator out of sequence, or not stop the machine when it should. This is the main type of troubleshooting problem presented in this course.

Another type of problem is one where either the speed, position, force, or acceleration of the actuator varies from the specifi cation. These problems take a somewhat different approach to solve than the one used here.


50

Step 2: Check the Status Indicators

After identifying the problem, the next step is to narrow it down to a particular subsystem. The PLC’s status indicators provide information that can help because each part of the PLC system tends to affect a particular indicator. The following fl owchart shows a suggested order in which status indicators could be checked. If no indicators show an abnormal status, the problem is most likely in the I/O system, as shown in the fl ow chart.

After determining the status of the indicators, proceed to step 3 to troubleshoot the subsystem.

Figure 40. Master PLC Troubleshooting Flowchart

PLC-CONTROLLEDSYSTEM HAS

MALFUNCTIONED

GO TOPOWER SUPPLY

TROUBLESHOOTINGFLOWCHART

CHECKPOWER SUPPLY

DC OKINDICATOR

CHECK FAULTINDICATORS

ON PROCESSOR MODULE

GO TOI/O SUBSYSTEM


GO TOPROCESSOR SUBSYSTEM


SF Red

Off

On

Off

CHECK STATUS INDICATORS ONALL INPUT AND

OUTPUT MODULES

At LeastOne On

TROUBLESHOOTMASTER CONTROL

RELAY CIRCUITAll Off

MASTER PLCTROUBLESHOOTING


51

Step 3: Troubleshoot the PLC Subsystem

The PLC’s status indicators should lead a troubleshooter to the faulted subsystem. Earlier materials provided fl owcharts and test procedures for the PLC’s various subsystems. A master troubleshooting fl owchart, like the one shown in fi gure 40 uses the PLC’s status indicators to direct the user to the failed subsystem and its troubleshooting fl owchart.

As an example, a technician using the master troubleshooting fl owchart fi nds that the power supply’s DC 24V indicator is off. The fl owchart identifi es the power supply as suspect and directs the technician to power supply troubleshooting fl ow-chart to perform tests on that subsystem (fi gures 41 and 42).

Figures 43 and 44 show the troubleshooting fl ow chart for the processor. These are the same charts used earlier but they have been modifi ed to show their tie-in to the Master PLC Indicator Flow Chart.

Figures 45 and 46 show the fi nal troubleshooting fl ow chart, which covers I/O and program troubleshooting. Use this chart if all status indicators appear to be normal. The problem is most likely either a fault in one of the I/O devices, I/O modules, or the software program.


52

Figure 41. Power Supply Troubleshooting Flowchart, Sheet 1

Off

CHECK MAIN POWERCIRCUIT’S DISCONNECT

SWITCH

CHECK INCOMINGVOLTAGE AT

POWER SUPPLYINPUT TERMINALS

OnOff

On

• TROUBLESHOOTPOWER WIRING:− DISCONNECT− MAIN FUSES− WIRING

• REPAIR PROBLEM

Off orBelow Normal

FINISHEDCHECKPOWER

INDICATOROff

VoltageNormal

GO TO SHEET 2 OF POWER SUPPLY TROUBLESHOOTING

FLOW CHART

TURNON

SWITCH

FINISHEDCHECKPOWER

INDICATOR

On

POWER SUPPLYTROUBLESHOOTING

(DC OK OFF)


53

Figure 42. Power Supply Troubleshooting Flowchart, Sheet 2

• TURN OFF POWER SUPPLY• REMOVE P/S CONNECTIONS TO

PROCESSOR MODULEAND I/O LOADS

• POWER UP P/S

CHECK POWERINDICATOR

REPLACEPOWER SUPPLY

• TURN OFF POWER• RE-CONNECT

PROCESSOR MODULE• TURN ON POWER SUPPLY


REPLACE THEPROCESSOR

• TURN OFF POWER SUPPLY• RE-CONNECT LOADS

ONE AT A TIME• TURN ON POWER SUPPLY


ENTER FROM SHEET 1 OF POWER SUPPLY TROUBLESHOOTING

FLOW CHART

• CALCULATE POWER SUPPLYLOAD TO DETERMINE IF ITIS WITHIN SUPPLY RATING No

REPLACE WITHLARGER ORREDUNDANT SUPPLY

Yes

REPAIR ORREPLACE LOAD

ALL CHECKSCOMPLETE

CALL PLANTENGINEER

On

On

On

Off

Off

Off

Off


54

Figure 43. Processor Subsystem Troubleshooting Flowchart, Sheet 1

PROCESSOR SUBSYSTEMTROUBLESHOOTING

(SF INDICATOR SOLID RED)

CHECK PROCESSORDIAGNOSTIC BUFFER

DETERMINE FAULT TYPEAND LOCATION

CORRECTPROGRAM

ERROR

DOWNLOADPROGRAM

CHECK FAULTINDICATOR

FINISHED

Off

CALL PLANT ENGINEEROR SIEMENS SUPPORT

Red

TROUBLESHOOTNON-PROGRAMMING ERROR FAULT

GO TO SHEET 2

PROGRAMMINGERROR No

Yes


55

Figure 44. Processor Subsystem Troubleshooting Flowchart, Sheet 2

• RESET MEMORY• DOWNLOAD

PROGRAM

DOES PROCESSOR HAVEA MEMORY MODULE?

CYCLE PLC TO STOPAND THEN BACK

TO RUN

CHECK SFINDICATOR,IS IT OFF?

CHECK INSTALLATIONOF

MEMORY MODULE ORMMC CARD

TURN ON POWER

• SET PLC TO STOPMODE

• RESET MEMORY

CHECK FAULTINDICATOR STATUS

RESTORE PROGRAMAND RETURNTO RUN MODE Off

REPLACEPROCESSOR

Red

Yes

No

Yes

No

NON-PROGRAMMINGERROR FAULT

TROUBLESHOOTING(SHEET 2)

FINISHED

TURN OFFPOWER


56

Figure 45. I/O Subsystem Troubleshooting Flowchart, Sheet 1

OUTPUT DEVICEWOULD NOT

CHECK I/O POWER ATOUTPUT MODULE

SUPPLY TERMINALS

FIND THE INSTRUCTIONPREVENTING OUTPUT

FROM TURNING ON

IS IT AN -] [ -?

IS IT AN -] / [ - ?

CONTINUE TO EXAMINEUSER PROGRAM TODETERMINE WHICH

NETWORK CONTAINSTHE PROBLEM.

MEASURE VOLTAGE AT OUTPUT TERMINALS

FORCE IT ON ANDOFF TO TEST


GO TOSHEET 2 OF I/O

TROUBLESHOOTINGFLOW CHART

IS ADDRESS AN INPUT?


CHECK INPUT STATUSINDICATOR:-IF ON, CHECK INPUT MODULE, OR INTERCONNECT CABLES.-IF OFF, CHECK INPUT FIELD DEVICE, FIELD WIRING, OR VOLTAGE.

CHECK INPUT STATUSINDICATOR:-IF OFF, CHECK INPUT MODULE, OR INTERCONNECT CABLES.-IF ON, CHECK INPUT FIELD DEVICE, FIELD WIRING, OR VOLTAGE.

Turn Off

Turn On

Off

False

CHECK STATUS OFOUTPUT INSTRUCTION

ON TERMINALTrue

Yes

Yes

No

No

No

No

Yes

Yes

VoltageNormal

I/O SUBSYSTEMTROUBLESHOOTING

(PLC INDICATORS NORMAL)

On

GO TO SHEET 2 OF

I/O TROUBLESHOOTING FLOW CHART

C

TROUBLESHOOTMASTER CONTROL

RELAY CIRCUIT Off

CHECK OUTPUTTERMINAL'S STATUS

INDICATOR ONOUTPUT MODULE

Turn On

CHECK• OUTPUT DEVICE

FAILURE• OUTPUT WIRING

OPEN• WIRING TERMINAL

ASSEMBLY FAILURE


No Voltage WhenForced On


57

Figure 46. I/O Subsystem Troubleshooting Flowchart, Sheet 2

FIND THE INSTRUCTIONWHICH IS SUPPOSED TOTURN OFF THE OUTPUT

INSTRUCTION

*LOCATE COIL FOR INTERNAL ADDRESS*TROUBLESHOOT INPUTS AND/OR OUTPUTS AS NECESSARY


IS ADDRESS AN OUTPUT?

*TEST INPUT DEVICE*TEST INPUT MODULE*REPLACE DEFECTIVE COMPONENTS

No

No

Yes

Yes

*TEST OUTPUT DEVICE, FIELD WIRING FOR SHORT

*TEST OUTPUT MODULE FOR SHORT

True

False

On

Off

I/O SUBSYSTEMTROUBLESHOOTING

(SHEET 2)

CHECK SUSPECTED DEVICEOUTPUT MODULE STATUS

INDICATOR

CHECK STATUS OF OUTPUT

INSTRUCTION

C

*TEST OUTPUT DEVICE*TEST OUTPUT MODULE*REPAIR OR REPLACE DEFECTIVE COMPONENTS


58

Step 4: Test the Suspected Component

Once the fault has been narrowed down to a suspected component, either test the component out-of-circuit, substitute a known good component, or isolate the component and operate the rest of the system. The choice depends on the type of component. If the suspected component is a PLC module of some type, a known good component can be substituted. If the fault is in an I/O device, it may be tested out-of-circuit.

Step 5: Repair or Replace the Suspected Component

Once the faulty component has been identifi ed, repair or replace the compo-nent. In general, any bad PLC components will have to be replaced in the fi eld and sent to the factory for repair or discarded.

Step 6: Test the Repaired System

After the component has been repaired or replaced, test the system manually before returning it to production. Also, carefully watch the system to see if there are any other faults that may have been hidden by the fi rst fault.


59

SKILL 4 USE A SIX-STEP SEQUENCE TO TROUBLESHOOT A MECHATRONICS STATION

Procedure Overview

In this procedure, you will step through the six-step troubleshooting sequence described earlier. To do this, you will use the fault insertion system’s single fault mode to produce a symptom. This will show you how the six-step troubleshooting sequence works. In the next skill, you will use the fault insertion system’s random fault mode to apply your new troubleshooting skills.

1. Perform the following substeps to prepare a mechatronics station for operation.

A. Obtain a mechatronics station and set it up for single station operation.

Make sure any fi xtures or bins are installed for single station operation.

B. Verify that the 87-FS Fault Box is installed and connected to the station.

C. Verify that a USB communications cable is inserted into the PREVIOUS STATION/PC socket and connected to a USB port on the PC.

D. Verify that an adapter cable connects the PLC to the PC. 2. Perform the following safety check before you begin working on the station.






Tie up long hair







60



B. Remove the lockout/tagout device from the electrical power source.

C. Remove the lockout/tagout device from the pneumatic power source.

D. Turn on the air to the station by shifting the lever on the lockout valve.

E. Set the station’s air supply regulator to 50 pis/345 kPa.

F. Turn the station’s ON/OFF switch to the ON position 4. Perform the following substeps to create a project.

A. Start and log in to the PC.

B. Start the SIMATIC Manager.

C. Create a new PLC project named L2S4_MS#_xxx where # is the Mecha-tronics station number (1-7) and xxx represents your initials.

D. Insert a SIMATIC 300 Station into the project.

E. Confi gure the hardware for the project.


61

F. Open OB1 and enter the ladder program shown in fi gure 48.

If you are using the 87-MS5 station, make the following address changes:

Cylinder Retracted = I 1.3

Cylinder Extended = I 1.2

Figure 48. OB1 Ladder Program

"AUTOCYCLE"

M1.0

"CONTROLPOWER ON"

Q4.0

"OUTPUTPOWER ON"

I0.3

"SS1 AUTOMODE"

I1.1"STOP"

I0.1"START"

I0.0

"AUTOCYCLE"

M1.0

NETWORK 1 : TITLE:

NETWORK 2 : TITLE:

"MANUALCYCLE"

M1.1

"SS1RESET"

I1.0

NETWORK 3 : TITLE:

"SS1 AUTOMODE"

I1.1

"CYLINDEREXTENDED"

I1.3

"CONTROLPOWER ON"

Q4.0

"EXTENDCYL"Q4.5

NETWORK 4 : TITLE:

"START"I0.0

"AUTOCYCLE"

M1.0

"CYLINDERRETRACTED"

I1.2

"EXTENDCYL"Q4.5

"MANUALCYCLE"

M1.1


62

G. Download the program to the PLC.

H. Place the PLC in the RUN mode.

I. Go online to the processor and click the Monitor button on the tool bar.

J. Move the CYCLE SELECT switch to RESET then to AUTO.

K. Verify that no valve components are at the input to the station you are using.

L. Press and release the START pushbutton to start the cycle.

The cylinder controlled by output Q4.5 should extend fully then retract fully and repeat the cycle.

Contact your instructor if the cycle is not correct.

M. Once you have verifi ed that the station cycles through its functions correctly, press and release the STOP pushbutton to stop the cycle.

5. Perform the following substeps to open and log in to FaultPro software. FaultPro is the software that induces faults into the mechatronics station to

provide troubleshooting scenarios. Your instructor should have created a user account for you and given you a username and password to open the software.

A. Minimize Step 7 software but do not close.

B. Locate the FaultPro Student icon, shown in fi gure 49, on the PC desktop.

Figure 49. Fault Pro Student Icon


63

C. Double-click the icon to open the software.

FaultPro software can run on a server with students accessing it as a client or as a stand-alone single installation on a PC.

If the FaultPro icon is not found on the desktop, the software may be opened by clicking Start on the taskbar followed by All Programs, FaultPro, and then Student.

A splash screen should open followed by the login screen shown in fi gure 50.

Figure 50. FaultPro Student Window


64

D. Enter your login ID and Password then click the OK button.

Contact your instructor if you don’t know or have forgotten your Login ID and/or Password.

The Student Options window in fi gure 51 should open.

Figure 51. Student Options Window

6. Perform the following substeps to insert a fault into the system and troubleshoot the fault using the six-step troubleshooting sequence.

Faults are inserted into the mechatronics stations in two ways: Single Fault Mode or Random Fault Mode.

In Single Fault Mode, the user manually enters faults into the system. This mode helps the user by familiarizing him or her with the symptoms of a specifi c fault and how to troubleshoot the fault. You will use this mode for the remainder of this LAP.

In Random Fault Mode, faults are predefi ned and entered into the system automatically. You will use this function in a later LAP.

SINGLE FAULTMODE

BUTTON


65

A. Obtain copies of the Master PLC Troubleshooting and Troubleshooting Process Recording Chart from your instructor.

B. Open the Class folder, if required.

C. Open the LAP 2 option.

D. Select the Skill 4 option.

E. Click the Single Fault Mode button to select the option.

The dialog shown in fi gure 52 should be displayed.

This dialog allows the user to enter faults into the PLC system.

Figure 52. Single Fault Mode Window

F. Verify that the station name matches the one on which you are working.

If not, select the correct one.

The table in fi gure 53 shows the station names for the different mecha-tronics stations.

G. Place the cursor on the Enter Fault fi eld, type 8 (6 for the 87-MS5) and click the Enter button to enable the fault.

H. Press and release the START pushbutton to start the cycle.

I. Observe the station for proper operation. Record your observation.

Observation: _______________________________________________

You should have recorded that the cylinder extended to its full travel but did not retract.

ENTERFAULTFIELD

STATIONSELECT

DROP LIST


66

J. Record the failure as the symptom observed in the Troubleshooting Process Recording Chart shown in fi gure 53.

You should have recorded the failure you observed in detail, such as “Feeder cylinder did not retract after extending.”

You have completed the fi rst step in the six-step PLC troubleshooting sequence, identify the problem or symptom.

TROUBLESHOOTING PROCESS RECORDING CHART

Symptom Observed: Cylinder did not retract after extending

Step Check Made Result

1

2

3

4

5

6

7

Remedy:

Figure 53. Troubleshooting Process Recording Chart


67

7. Perform the following substeps to troubleshoot the failure observed in Step 6.

A. Obtain copies of the PLC Troubleshooting Flowcharts from your instructor.

B. Perform the fi rst step in the Master PLC Troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Sheet. Your sheet should look similar to the one in fi gure 54.




1 You observe that PLC-Controller system has malfunctioned

2

3

4

5

6

7

Remedy:


This step confi rms the system is not working correctly.


68

C. Perform the next step in the Master PLC Troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Sheet. Your sheet should look similar to the one shown in fi gure 55.




1 You observe that PLC-Controlled system has malfunctioned

Yes

2 Check the power supply DC OK indicator On

3

4

5

6

7

Remedy:


Checking the PLC and control power supply is always a good fi rst step when troubleshooting control systems.

This also completes the second step in the six-step PLC troubleshooting sequence, check the status indicators.


69

D. Perform the next step in the Master PLC Troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Sheet. Your sheet should look similar to the one shown in fi gure 56.





Yes


3 Check processor fault indicators Normal

4

5

6

7

Remedy:


This step eliminates a PLC fault as the cause of the malfunction.


70

E. Perform the next step in the Master PLC Troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Sheet. Your sheet should look similar to the one shown in fi gure 57.





Yes



4 Check I/O status indicators Normal

5

6

7

Remedy:


This step eliminates a failure in the MCR circuit.


71

F. Perform the next step in the Master PLC Troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Sheet. Your sheet should look similar to the one shown in fi gure 58.





Yes




5 Troubleshoot I/O subsystem

6

7

Remedy:


The previous steps have eliminated the processor and the power supply as sources of the problem. The failure is most likely caused by a failed input or output device or possibly an input or output module.

The procedure also takes you to the third step in the six-step PLC trouble-shooting sequence, troubleshoot the PLC subsystem, or in this instance, the I/O subsystem. The next several steps will isolate the problem to a specifi c component to test.


72

8. Perform the following substeps to troubleshoot the I/O subsystem.

A. Perform the fi rst step in the I/O Subsystem Troubleshooting Flowchart. Record the step and results in the Troubleshooting Process Recording Chart. Your chart should look similar to the one shown in fi gure 59.





Yes





6 Would an output not turn on/off Off

7

Remedy:


Because the output would not turn off, the troubleshooting fl owchart assumes the system has control power and directed you to a fl owchart for troubleshooting the output module and control logic.


73

B. Perform the fi rst step in the I/O Subsystem Sheet 2 troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Sheet. You may wish to start a new Troubleshooting Process Recording Chart, as shown in fi gure 60.


Symptom Observed: Cylinder did not retract after extending; Problem isolated to I/O subsystem


1 Check suspected device output module status indicator

On

2

3

4

5

6

7

Remedy:


The output status indicator was on, eliminating fi eld wiring of the device as the failed component.


74

C. Perform the next step in the I/O Subsystem Sheet 2 troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Chart.

Your chart should look similar to the one in fi gure 61.




1 Check suspected device output module indicator

On

2 Check status of output instruction True

3

4

5

6

7

Remedy:


Although the symptom was that the cylinder would not retract, the problem is not caused by the output system. The cylinder was held in the extended position by the processor logic. This points to a problem with an input device or an output contact causing the network to remain true when that step of the cycle is fi nished.

The address for the suspected component is found from the PLC I/O Drawing for the machine, which in this example is Q4.5.


75

D. Perform the next step in the I/O Subsystem Sheet 2 troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Sheet. Your chart should look similar to the one shown in fi gure 62.





On


3 Find the instruction which is supposed to turn off the output instruction

N.C. I1.3(N.C. I1.2 87-MS5)

4

5

6

7

Remedy:


Usually, logic networks are programmed in a progression from start/stop, seal in, end step, and output from left to right. In this network, the normally closed contact with address I1.3 (I1.2 for the 87-MS5), “Cylinder Extended” controls when the output should be turned off.


76

E. Perform the next step in the I/O Subsystem Sheet 2 troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Sheet. . Your chart should look similar to the one shown in fi gure 63.





On



N.C. I1.3(N.C. I1.2 87-MS5)

4 Is the address an input Yes

5

6

7

Remedy:


This step determines if the problem is from an input device or module or from somewhere else in the logic routine such as a contact from an output or an internal coil. In this example, the input is an fi eld device at address I1.3 (I1.2 for the 87-MS5).


77

F. Perform the next step in the I/O Subsystem Sheet 2 troubleshooting fl owchart. Record the step and results in the Troubleshooting Process Recording Sheet. . Your chart should look similar to the one shown in fi gure 64.





On



N.C. I1.3(N.C. I1.2 87-MS5)

4 Is the address an input Yes

5 Test input device, test input module, re-place defective components.

Done

6

7

Remedy: Cylinder Extended switch failed; replaced switch


The normally closed contact at address I1.3 (I1.2 for the 87-MS5) is highlighted true in the ladder network, which means the controller is not receiving an indication that the cylinder is extended. Using the proce-dures for troubleshooting the input device and module from the previous LAP, you should have discovered there was no voltage at the input module terminal from the switch connected to I1.3 (I1.2 for the 87-MS5).

Fault 8 (6 for the 87-MS5) simulates a failed Cylinder Extended switch. Replace the switch to remedy the problem.

You have completed step four of the troubleshooting sequence, test the suspected component.

9. Press and release the mechatronics station STOP pushbutton. The cylinder should retract. 10. Click the Clear Fault button in the FaultPro software to remove the fault. Removing the fault represents replacing the switch, which completes step

fi ve of the troubleshooting sequence, repair or replace suspected component.


78

11. Press and release the START pushbutton. The cylinder should extend fully then retract fully and repeat the cycle. This represents the last step in the troubleshooting sequence, test the repaired

system. 12. Press and release the STOP pushbutton to stop the cycle. You have successfully used a six-step troubleshooting sequence to determine

the cause of a mechatronics station malfunction, resolve the problem and test the system.

13. Perform the following substeps to induce a fault into a mechatronics station, determine the symptom, troubleshoot, and resolve the problem it produced.

A. Type 32 in the Enter Fault fi eld of the FaultPro Single Fault Mode window and click the Enter button.

The Single Fault Mode dialog should still be displayed from the previous fault.

B. Observe the mechatronics station and record any malfunctions in the space provided.

Malfunction ________________________________________________

You should have observed that a cylinder extended without pressing the start pushbutton.

C. Troubleshoot the malfunction using the six-step troubleshooting sequence and the troubleshooting fl owcharts. Document your steps and results in a Troubleshooting Process Recording Chart.

Your chart(s) should look similar to the ones in fi gures 65 and 66.


Symptom Observed: Cylinder extended without pressing the Start pushbutton



Yes





6

7

Remedy:



79

The Troubleshooting Process Recording Chart shown in fi gure 65 directed you to the I/O Subsystem fl owchart. The fi rst entry, Output Device would not turn off, directs you to sheet 2 of the fl owchart. The results from that fl owchart are shown in fi gure 66.





On

2 Check status of output instruction False

3 Test output module for short Shorted

4

5

6

7

Remedy:


In this failure, the output was on when the ladder logic commanded it off. The output module was shorted. This is the typical failure mode for a PLC output module with solid-state outputs.

Fault 32 emulates a shorted point on an output module.

D. Click the Clear Fault button in FaultPro software to remove the fault.

Removing the fault represents replacing the output module.

E. Press and release the START pushbutton to start the cycle.

The cylinder should extend fully then retract fully and repeat the cycle.

F. Press and release the STOP pushbutton to stop the cycle.

G. Click the Exit button to close the Single Fault mode.

The Student Options window should open.

H. Click the Logout button to close the Student Options window.

I. Click the Exit button to close FaultPro.


80

SKILL 5 TROUBLESHOOT A MECHATRONICS STATION

Procedure Overview

In this procedure, you will use the FaultPro fault insertion system to randomly insert faults into a mechatronics system. To begin, you will use the Practice Mode. You will repeat the procedure using the Test Mode. Your Test Mode score will be recorded as part of your evaluation.

1. Perform the following substeps to prepare a mechatronics station for operation.

A. Verify the mechatronics station you are using is the same one as in the previous skill and is set up in the same manner.

B. Verify that a USB communications cable is inserted into the PREVIOUS STATION/PC socket and connected to a USB port on the PC.

C. Verify that a PC Adapter cable connects the PLC to the PC.

D. Verify that the mechatronics station is powered up.

E. Verify that the project L2S4_MS#_xxx from the previous skill is loaded into the PLC and the PLC is in the RUN mode.

2. Perform the following safety check before you begin working on the station. Make sure that you can answer yes to each item before proceeding.





Tie up long hair







81

3. Obtain copies of the Mechatronics Troubleshooting Flowcharts, the Troubleshooting Process Recording Chart, and a multimeter from your instructor.

4. You should be logged in to the FaultPro software from the previous skill. If so, continue to Step 5. Otherwise, perform the following substeps to start up and log in to the FaultPro fault insertion software.

In this skill, you will use FaultPro software to insert faults into the PLC trainer and then troubleshoot the fault. This will help you to recognize and quickly diagnose faults in the fi eld.

A. Double-click the FaultPro-Student icon to start the FaultPro software.

The FaultPro splash screen should appear briefl y, followed by the FaultPro login screen.

Notify the instructor if you do not have a student ID and Password.

B. Type your teacher-assigned login ID.

C. Press the Tab key to continue to Password.

D. Type your teacher-assigned password.

E. Press Enter to enter the password and log in to the FaultPro software.

The Student Options window should open. 5. Perform the following substeps to select a FaultPro template and enter the

Random Fault Practice Mode for your mechatronics station. Fault templates are fi les that contain a predefi ned set of faults that can be

randomly inserted, one at a time, by the fault insertion system.


82

A. Open the Class folder, if required.

Figure 68. Student Menu Expanded to Show LAPs

B. Click the plus sign to the left of LAP 2: Mechatronics System Trouble-shooting to expand it.

The skills for LAP 2 should be displayed as shown in fi gure 69. One or more skills should be displayed.

Figure 69. Student Menu Expanded to Show Skills

SINGLEFAULTMODE

BUTTON


83

C. Click the icon for Skill 5: Troubleshoot a Mechatronics System.

The Student Menu should change similar to that shown in fi gure 70.

Figure 70. Student Menu with Skill Selected

RANDOMFAULTMODE

BUTTON


84

D. Click the Random Fault Mode button.

The dialog in fi gure 71 should be displayed.

Practice mode gives you an opportunity to practice troubleshooting randomly generated faults. Once you have practiced all of the faults in the skill template, you will use the Test mode to troubleshoot them again and be graded on your performance.

Figure 71. Random Fault Mode Options

E. Verify that Practice mode is selected and click the OK button.

The Practice Mode dialog similar to the one in fi gure 72 should be displayed.

Figure 72. FaultPro Practice Mode Dialog

Take a moment to familiarize yourself with the dialog and its various fi elds.

F. Click the Start button to insert the fi rst fault.

A fault has been inserted into the system and the software prompts you to enter the fault number (a blinking cursor appears in the Enter the suspected fault number: fi eld.)

STATUSFIELD

STARTBUTTON


85

6. Perform the following substeps to troubleshoot the mechatronics fault.

A. Check the PLC status indicators and record their status in the chart in fi gure 73.

MODULE INDICATOR STATUS

Processor

SF

BF, or BF1 and BF2

DC5V

FRCE

RUN

STOP

MAINT

Input Modules Input Status

Output Modules Output Status

Power Supply DC ON

Figure 73. PLC Status and Power Supply Indicators

B. Attempt to operate the station by pressing and releasing the START pushbutton.

If the station fails to operate in AUTO mode, change the CYCLE SELECT switch to MANUAL and press the START pushbutton again.

Observe any symptoms and record them in the Troubleshooting Process Recording Chart shown in fi gure 74.


Symptom Observed:


1

2

3

4

5

6

7

Remedy:



86

C. Use the troubleshooting fl owcharts to troubleshoot the problem, recording each check and result in the Troubleshooting Process Recording Chart.

Once you think you have determined the fault, fi nd it in the FaultPro Available Faults for Selected Skill scrollbox.

D. Type the number of the suspected fault and click the Enter button, or press the Enter key on the keyboard.

If the answer is correct, the status fi eld will display Answer is Correct, as shown in fi gure 75.

Figure 75. Answer is Correct


87

If the answer is incorrect, the status fi eld will display Answer is not correct, as shown in fi gure 76.

Figure 76. Answer is Incorrect

If your answer is incorrect, you can:• Click the Try Again button to troubleshoot the current fault again.• Click the Clear button, and then the Next Fault button to continue to the next fault.• Click the Show Fault button to display the current fault.

E. Click the Clear button, and then the Next Fault button to continue to the next fault.

FaultPro will remove the current fault from the system and insert another in its place (as long as faults remain in the template.) In some cases, you may need to press the mechatronics station’s OUTPUT POWER push-button to restore power to the outputs.

F. Repeat substeps A through E to troubleshoot all faults in the template.

In practice mode, FaultPro allows you to continue to practice. When all faults have been attempted, the status fi eld will display No Faults Left.

G. Click the Exit button to exit the Random Fault dialog.


H. If you feel comfortable troubleshooting this mechatronics project, continue to Step 7 to enter the Random Fault Test Mode.

If not, repeat Step 6 for more practice.


88

7. Perform the following substeps to induce random faults into the mechatronics station in the Test Mode.

A. From the Student Options window, click the Random Fault Mode button.

The Random Fault Mode Options dialog should be displayed.

B. Click the Test button then click the OK button to continue.

The Test Mode dialog, shown in fi gure 77 should be displayed.

You should notice it is similar to the Practice Mode dialog with the excep-tion of the Show Fault button. The Test Mode will record the amount of time that you take to troubleshoot the fault, as well as the number of tries that you take. This information will be used in the assessment of your grade.

Figure 77. Test Mode Dialog

C. Click the FaultPro Start button to insert the fi rst fault.


D. Use the procedure from Step 6.

E. After you have attempted all faults presented, click the Exit button to exit the Test Mode.

You will be returned to the Student Options window.


89

F. Click the View Grades button to see your score.

The window shows the skill information and a summary of the trouble-shooting session. The grade is a combination of the number of faults mastered, the number of attempts, and the time needed to troubleshoot them. Your screen will show details for the Total Faults, Total Tries, Total Time, and Mastered fi elds.

G. Click the Close button in the top right corner to exit the Grade View window.


H. Click the Logout button to close the Student Options window.

The FaultPro opening dialog should be displayed.

I. Click the Exit button to exit the FaultPro Software. 8. Power down the mechatronics station and shut down the PC.


90


1. PLC troubleshooters should use a(n) ______ approach to isolate the cause of a problem.

2. A(n) ___________ is a graphical method of troubleshooting that uses block symbols connected by fl ow lines to show the sequence of steps to follow.

3. The most common method of isolating circuit and component problems is to take voltage, current, and resistance ______.

4. A mechanical device, such as a motor or solenoid, may make a(n) ___________ when it fails.

5. After the component has been repaired or replaced, test the system ______ before returning it to production.


91

SEGMENT 3PLC SOFTWARE TROUBLESHOOTING TOOLS

OBJECTIVE 8 DESCRIBE THE OPERATION OF THE SEARCH FUNCTION AND GIVE AN APPLICATION

PLC ladder logic programs often contain more networks than it is possible to display on the programming terminal at one time. Therefore, most program-ming packages provide search functions to locate certain instructions or parts of programs. Step 7 provides a Find/Replace function in the LAD/STL/FBD Editor to locate and replace instructions or text strings. The text strings can be either symbols or network titles and comments. The Find/Replace dialog is opened by selecting Find/Replace from the Edit menu, as shown in fi gure 78. The Find/Replace dialog is shown in fi gure 79.

Figure 78. Opening the Find/Replace Dialog

EDITMENU FIND/REPLACE

OPTION


92

Figure 79. Find/Replace Dialog

Any program address or text string in the opened block can be found by entering the address or text string in the Find what: box, and pressing the Find button. For example, fi gure 80 shows a Find/Replace dialog with the address M4.6 entered in the Find what: box. When the Find button is pressed, the fi rst occurrence of the address is highlighted in blue. Clicking the Find button again will cause the software to display the next occurrence of the address M4.6.

Figure 80. Find/Replace Applications


93

OBJECTIVE 9 DESCRIBE THE OPERATION OF THE GO TO FUNCTION AND GIVE AN APPLICATION

The Go To function is similar to the Find/Replace function, but it is more powerful. It can be used to search for all occurrences of an address in any of the project’s blocks, even if they are not open. The Go To dialog is opened by selecting Go To from the Edit menu, or by right-clicking on any address or instruction displayed in the LAD/STL/FBD Editor, selecting Go To, and selecting Location from the shortcut menu, as shown in fi gure 81. The Go To Location dialog is shown in fi gure 82.

Figure 81. Opening the Go To Location Dialog


94

Figure 82. Go To Location Dialog

The Go To Location dialog contains the following information:

•Address - This fi eld displays the address used to open the Go To Location dialog if it was opened by right-clicking on an address. If it was opened from the Edit menu, it will be empty until an address is entered. The absolute address, symbolic name, and comment for the entry selected are displayed at the top of the table. All locations of the selected address in the project are displayed in the table. Each row corresponds to a location entry.

•Block - The block where the address is located.

•Block Symbol - The block symbol, if one has been programmed into the project’s symbol table.

•Details - Displays the following information: • Network - The fi rst item displayed is the network the address is used in. For example, NW 3, listed in the fi rst row of the table indicates that the address is used in Network 3 of FC 43.

GO TOBUTTON

NETWORK

INSTRUCTIONTYPE

LANGUAGE

TYPE

<< AND >>BUTTONS

OVERLAPPINGACCESS TO

MEMORYAREASOPTION

SELECTIONFIELD

ALLSELECTION

BLOCK

BLOCKSYMBOL

SELECTEDADDRESSSYMBOL DETAILS

STARTING POINT BUTTON

CLOSEBUTTON


95

• Instruction Type • / = - The address is used for an output coil.• /A - The address is used with a N.O. contact in the main network path.• /AN - The address is used with a N.C. contact in the main network path.• /O - The address is used with a N.O. contact in a network branch.• /ON - The address is used with a N.C. contact in a network branch.

• Type - • R - The address is read from this location.• W - The address is written to/from this location.• RW - The address is read and written to/from this location.• ? - The access type could not be determined. • Language - Language that the listed block is written in.

•All - Select to display all locations of the address in the project.

•Selection - Select to display a limited set of the address locations in the project based on the access type.

•Overlapping access to memory areas - This option selects all the locations in which address areas that overlap with the selected address. For example, if address Q4.0 is selected, any occurrence of QB4, QW4, QD4 would also be displayed (these are not the only word addresses that overlap with Q4.0).

•Display - This button is activated when a change is made to the address fi eld. Clicking the button displays the table listed on the dialog.

•Go To - Selecting Go To causes the software to open the block selected in the table and display the network where the address is used.

•Close - Closes the Go To Location dialog.

•Starting Point - Selecting Starting Point causes the block and network from which the dialog box was opened to be displayed.

•<< and >> - Forward and rewind through the selections that have been made in the table since the dialog was opened.


96

For example, if the fi rst item in the table is selected and the Go To button is pressed, FC 43 is opened and Network 3 is displayed, as shown in fi gure 83. Notice that signal name, I0.3, the symbol, Auto Mode, and the Symbol Comment, Auto Mode=1 Cycle Mode=0 is displayed in the Address area at the top of the dialog. Notice on Network 3 that address I0.3 is assigned to a N.C. contact (/AN) on the network.

Figure 83. Go To Application


97

SKILL 6 USE THE SEARCH AND GO TO FUNCTIONS TO FIND AN INSTRUCTION

Procedure Overview

In this procedure, you will use the Find/Replace and Go To functions to search for specifi c instances of an address in a mechatronics project. This will familiarize you with the search functions available in a STEP 7 project.

1. Perform the following substeps to open a mechatronics project.

A. Turn on the PC and open the SIMATIC Manager.

B. Open the mechatronics project Feeder.

Project Feeder controls the operation of the 87-MS1 Pick and Place Feeding station and is representative of the other mechatronics projects. Skills gained in this project can be applied to any other project.

The project was provided on a supplemental disk. If you cannot locate the project, contact your instructor.

C. Fully expand the project tree by selecting Expand All or Show All Levels from the View menu.

D. Double click Blocks to display the blocks in the right-hand window.

The project contains a System Data, OB1 and OB100 blocks.

E. Double-click OB1 to display the block’s networks.

OB1 is a 35-network program consisting of logic, timers, and other typical mechatronics control elements. Many inputs are used more than once in the project and contacts with coil addresses are common. The STEP 7 search tools will help you locate specifi c addresses in the networks.


98

2. Perform the following substeps to assure the OB1 display is confi gured to permit searching for addresses.

A part of block OB1 is displayed in fi gure 84. Notice that the logical address, such as I0.1, is displayed closest to the instruction while the description is shown above the logical address. The addresses must be displayed in this manner for the Find/Replace function to fi nd them.

Figure 84. OB1 Representative Rungs

LOGICALADDRESS

DESCRIPTION


99

A. Click View from the toolbar.

The drop menu shown in fi gure 85 should be displayed.

Figure 85. View Menu

B. Place the cursor over the Display with option.

The menu shown in fi gure 86 should be displayed.

Figure 86. Address Display Options

C. Verify that Symbolic Representation Ctrl+Q is not checked. If it is checked, click on the entry to remove the check.

You may also use the combination of the Ctrl and Q keys pressed together to toggle the address display.


100

3. Perform the following substeps to use the Find/Replace function to fi nd entries for I1.2 in OB1.

A. Verify that the cursor is on Network 1 in the block.

B. Select Find/Replace from the Edit menu.

The Find/Replace dialog should open as shown in fi gure 87.

If the Find/Replace dialog does not contain all of the fi elds shown in fi gure 87, click the More button to the right of the dialog to display additional options.

Figure 87. Find/Replace Dialog

C. Click the cursor in the Find what: fi eld.

D. Type I1.2 in the Find fi eld.

E. Click the Find button.

The software should highlight the fi rst occurrence of address I1.2 in Network 5 as shown in fi gure 88.

If the message “The search item was not found,” is displayed, click OK then verify that you typed the address correctly. Verify that Network 1 is selected. Close the Find/Replace utility and press Ctrl-Q then search again.

Figure 88. Address Found

ALL

FIND

FIND WHATBUTTON


101

F. Click the Find button.

The next occurrence of the address should be found and highlighted, in this case, Network 8.

G. Repeatedly click the Find button. Record the number of the networks where the address was found in the space provided.

Networks where found: _______________________________________

In addition to networks 5 and 8, you should have found the address I1.2 in networks, 9, 11, 15, 22, and 35.

You should have also observed that the address was found on both normally closed and normally open contacts. Only the address was searched, not the instruction type.

The search ended at the end of the block, displaying the message shown in fi gure 89.

Figure 89. End of Search Message

4. Perform the following substeps to display the location of all instructions with the same address.

A. Press the Ctrl and F keys together to open the Find/Replace dialog.

B. Type I1.3 in the Find what: fi eld.

C. Click the Find button.

You should have received the message the search item was not found. This message was displayed because the cursor was at the end of the block from the previous search.

D. Click OK to clear the message.

E. Click All in the Find/Replace dialog to highlight the selection with a bullet.

F. Click the Find button.

The search will begin from the current cursor position, roll over to the fi rst network, and continue searching downward until the address is found in Network 16.

You could have clicked From cursor up to search the block from end to start. However, the All option assures the entire block will be searched, a useful feature if a search for a new address is initiated from a network other than at the beginning or end of the block.


102

5. Perform the following substeps to locate all instances of an address within a block.

Often it is desirable to see every network where an address is used. This is particularly important when forcing inputs or outputs to determine the effect the force will have on the entire project.

A. Type Q4.5 in the Find what fi eld then click Find.

The next occurrence of the output address should be highlighted.

B. Right-click the address.

A drop menu will open similar to the one shown in fi gure 90.

Figure 90. Instruction Drop Menu

C. Place the cursor over Go To.

The options shown in fi gure 91 should be displayed.

Figure 91. Go To Option


103

D. Click Location... or select Ctrl+Alt+Q using the keyboard.

The Go To Location dialog similar to the one in fi gure 92 should be displayed.

The Go To Location dialog lists every instance of the address in the project. The information includes the location, network number, and if the instruction on a network is a read, write, or read/write instruction.

For example, the location highlighted in fi gure 94 is in OB1 which is named SVI Extend Feed Cycle, the instruction is in a branch of network 28 and reads its data from another source. The output coil for Q4.5 is in network 14, as indicated by W in the Type column at the top of the list.

Figure 92. Go To Location Dialog

E. Click on the writable instruction, the entry at the top of the list to select it.

Network 14 should be displayed. The coil for Q4.5 is found at the right of the network.

F. Click the Go To button.

G. Click the Starting Point button.

The display returns to the network where the Go To dialog was opened and closes the dialog.

Clicking the Close button also closes the dialog.

WRITABLEINSTRUCTION


104

6. Perform the following substeps to simulate using the Go To function for troubleshooting.

A. Examine the network in fi gure 93 to determine what conditions are required to enable output M30.3. Record your fi ndings in the space provided.

Requirement _______________________________________________

You should have recorded output Q4.7 needs to be enabled. A trouble-shooter would want to examine the network containing the coil for Q4.7.

Figure 93. Example Network

B. Scroll to Network 30 in the Feeder OB1 block.

C. Put the cursor on the normally open instruction with address Q4.7.

"MM PILOTCONTROL 3"

M30.3

"MR1PICKUP

RETRACTED"I1.4

"SV3BRETRACTPICKUP"

Q4.7

"MM PILOTCONTROL 3"

M30.3

"SS1RESET"

I1.0


105

D. Right-click the instruction then choose Go To and Location.

The Location dialog similar to the one in fi gure 94 should be displayed.

Figure 94. Go To Location Dialog for Q4.7

E. Identify the network that contains the coil for Q4.7 and record its number in the space provided.

Network __________________________________________________

You should have recorded Network 22.

F. Put the cursor on the row that contains the coil then either double-click or click the Go To button.

Network 22 should be displayed so you can troubleshoot the system to turn on Q4.7.

G. Click the Starting Point button to return to the original network.

You have successfully used the Go To function to simulate a trouble-shooting operation.

7. Power down the mechatronics station and shut down the PC.


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1. PLC ladder logic programs often contain more networks than it is possible to display on the ___________ at one time.

2. Most programming packages provide ___________ to locate certain instructions or parts of programs.

3. Step 7 provides a(n) ___________ function in the LAD/STL/FBD Editor to locate and replace instructions or text strings.

4. Any ___________ or ___________ in the opened block can be found by entering the address or text string in the Find what: box, and pressing the Find button.

5. The Go To function is similar to the ______ function, but it is more powerful.

6. The Go To function can be used to search for ______ occurrences of an address in any of the project’s blocks, even if they are not open.


107

SEGMENT 4TROUBLESHOOTING MECHATRONICS STATIONS

OBJECTIVE 10 DESCRIBE HOW TO USE A SEQUENCE OF OPERATIONTABLE TO TROUBLESHOOT A MECHATRONICS PROCESS

A sequence of operation table, such as the one in fi gure 95, identifi es a work-station’s inputs and outputs and their condition during each step in the process. Programmers and automation engineers usually develop the tables as an aid for developing the station’s program. The same sequence of operation table, however, can be used later to troubleshoot the workstation when it fails. Troubleshooters do this by comparing the status of the station’s I/O with that defi ned by the current steps (as defi ned by the sequence of operation table) to isolate the failed, or missing input or output.

Figure 95. Sequence of Operation Table

Typically, bullets represent the status indicators on the PLC’s input and output modules. Sometimes 0’s and 1’s are used. A solid bullet, or 1, means the indicator is illuminated. A hollow bullet, or 0, shows the indicator is dark. A legend on the table shows other conditions. For example, a bullet with its left side solid and the right hollow means the indicator was on at the beginning of the step but turned off during the step, such as when pressing and releasing the start pushbutton. This will be represented by a 1/0 if 0’s and 1’s are used.


108

What happens in each step is shown by the status of the I/O changing from one step to the next. In the example of fi gure 98, Step 0 shows the workstation idle and ready to start its cycle. The bullets show that the stop pushbutton is closed (I0.1), the emergency stop circuit is intact (I0.2), the output power is on (I0.3), the work-station is in auto mode (I1.1), the part feeder (I1.2), the pickup (I1.4) and traverse (I2.0) all are retracted, and the magazine has parts to feed (I2.7). No outputs are turned on while waiting for the start input.

Step 1, highlighted in fi gure 96, shows that the Start pushbutton (I0.0) has been pressed and released, which energized output Q4.5 to extend a part to the pick up position. The I/O status change shows that the green pilot light (Q4.0) is turned on to show the cycle has started. The steps continue until the station has completed its process.

Figure 96. Sequence of Operation Step

In a typical mechatronics failure, the process stops or hangs up before completing its cycle, sometimes skipping several steps in the process. This is usually caused by an input failing to turn on or off, preventing the process from continuing to its next step. The technician examines the output indicators to deter-mine the step where the process stopped. Then the input indicators for the next step are examined to determine which one or ones are not in the proper state.

Once the input or inputs preventing the process from continuing are identi-fi ed, the devices and I/O modules are tested using procedures covered earlier. The possible reasons for failure include a failed input device or a failed input module. Additionally, an output device may not have actuated the input sensor due to a failed device or output module.

START PUSHBUTTONSTATUS

ENERGIZED OUTPUTQ4.0


109

For example, the process has stopped and the technician observes the I/O indi-cators in the table of fi gure 97 are illuminated.

Inputs Outputs

I0.1 Q4.0 (fl ashing)

I0.2 Q4.5

I0.3 Q5.3

I0.4

I1.1

I1.3

I1.5

I2.0

I2.7

Figure 97. Illuminated Input and Output Indicators

Examining the station’s sequence of operation table, shown in fi gure 98, shows the combination of illuminated outputs the technician observed are found in Step 3. An anomaly is observed for output Q5.3, Vacuum On. From the sequence table, the output should have turned on momentarily then turned off in Step 3. However, this is the only step in the table where all three of the outputs are on at the same time.

Figure 98. Process Stops at Step 3INPUT CHANGE INDICATED

STEP


110

To determine which input has not changed state, the next step in the table is examined. The only input change from Step 3 to Step 4 is I2.6, Vacuum On, which should be illuminated. The input module indicator for the switch is dark. The process is waiting for the vacuum to turn on so the part can be picked up.

From the observations, the troubleshooter can conclude that the failure is isolated to the vacuum switch or its input module, the vacuum generator, the sole-noid supplying air to the generator, the plant air supply, or loss of control power. The last two potential failures can be eliminated because they operated correctly in earlier steps of the sequence.

Occasionally, the same set of outputs will be on for different steps as shown in fi gure 99, steps 5 and 7, which extends the pickup. The part is picked up in step 5 and placed in step 7. To determine which step is being executed, observe the input indicators. For example, in step 5, the traverse is retracted while in step 7 it is extended. Observation is also used to determine the step where the process stopped. If the pick assembly is over the pickup point, the system is executing step 5.

Figure 99. Steps with Same Outputs

Occasionally the inputs and outputs observed on the I/O modules will not be an exact match for those found in the sequence of operation table. For example, an output that enables an actuator may also trigger a timer that turns other outputs on or off. If the actuator fails, the bullets in the sequence could be a combination of the ones from the failed actuator and the results of the timer.


111

Some failures prevent the machine from starting its cycle. Troubleshoot those failures by comparing the start conditions in the sequence of operation table to determine which input or inputs do not match the requirements to start the machine.

For example, fi gure 100 shows the sequence of operation table for a typical mechatronics application. Step 0 shows the conditions necessary for the machine to start. Observing the PLC input indicators, the technician notes input I0.1 is not illuminated and would troubleshoot the Stop pushbutton.

Figure 100. Sequence of Operation Table Start Condition


112

SKILL 7 USE A SEQUENCE OF OPERATION TABLE TO TROUBLESHOOT A MECHATRONICS PROCESS

Procedure Overview

In this procedure, you will use a Sequence of Operation table to troubleshoot faults inserted into the mechatronics station. First, you will manually insert faults to gain experience using the table. Then you will troubleshoot randomly generated faults.

1. Perform the following substeps to prepare a Mechatronics station for operation.

A. Obtain a Mechatronics station and separate it from any other stations.

Make sure any fi xtures or bins are installed for single-station operation.

B. Verify that the 87-FS Fault Box is installed and connected to the station.

C. Verify that a USB communications cable is inserted into the PREVIOUS STATION/PC socket and connected to a USB port on the PC.






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113



B. Turn the station’s ON/OFF switch to the ON position 4. Perform the following substeps to download a program to the mechatronics

station and observe the station indicators.

A. Start the PC.


C. Open the program for your station as shown in the table of fi gure 102.

Station Project

87-MS1 Feeder

87-MS2 Gauging

87-MS3 Indexing



87-MS6 Torquing



D. Download the program to the PLC.

E. Place the PLC in the RUN mode. 5. Perform the following substeps to verify correct operation of the mechatronics

station.

A. Remove any valve components from the station except the knobs, screws, and spools for the 87-MS5 station.

B. Move the CYCLE SELECT switch to the RESET position then to AUTO.

C. Place an acrylic component at the input to the station.

D. Momentarily press the START pushbutton.

The station should execute its program and process the component. Contact your instructor if the sequence is not correct.

6. Obtain copies of the Sequence of Operation table for the station you are using, the Troubleshooting Flowcharts, and the Troubleshooting Process Recording Chart.


114

7. Perform the following substeps to start up and log in to the FaultPro fault insertion software.

A. Double-click the FaultPro Student icon to start the FaultPro software.

The FaultPro splash screen should appear briefl y, followed by the FaultPro login screen.

Notify the instructor if you do not have a student ID and password.

B. Type your teacher-assigned identifi cation into the login ID fi eld.

C. Press the Tab key to continue to Password,

D. Type your teacher-assigned password.

E. Press Enter to enter the password and log in to the FaultPro software.

The Student Options window should open. 8. Perform the following substeps to insert and troubleshoot a mechatronics

station fault.

A. Open the Class folder, is required.

B. Open the LAP 2 option.

C. Select the Skill 7 option.

D. Select your station in the drop-down list if it is not already selected.

E. Click the Single Fault Mode button.

The Single Fault Mode window will open. The station name should match the name of the station on which you are working.

F. Verify that the name of the station you are using matches that in the drop list. If they do not match, check your USB network cable connections.

G. Type 24 in the Enter Fault: fi eld and click Enter.

The status fi eld should show Fault 24 is Active.

H. Place an acrylic valve component at the input of the station and momen-tarily press the START pushbutton.

If you are using the 87-MS3 Indexing station, position the part with the thick side up.

I. Observe the operation of the station and record your observations in the space provided.

Observations: ______________________________________________

You should have observed the process stopped somewhere in its cycle.

J. Observe the power supply and PLC status indicators. Record any abnormal indications in the space provided.

Abnormal Indicators: ________________________________________

You should have observed all status indicators were normal.


115

K. Examine the station and determine which function it did not perform or what it did that it should not have done. This is the symptom of the failure. Record the station’s symptom in the Troubleshooting Process Recording Chart, as shown in fi gure 103.


Symptom Observed:


1

2

3

4

5

6

7

Remedy:


The table in fi gure 104 shows the symptom you should have recorded.

SYMPTOMS OBSERVED

Station Symptom

87-MS1 Pickup did not extend

87-MS2 Transfer did not extend

87-MS3 Lift cylinder did not extend

87-MS4 The acrylic release did not open

87-MS5 Clamp 1 did not extend

87-MS6 Slide did not move forward

87-MS7 Grip did not engage

Figure 104. Symptoms for Fault 24


116

L. Observe the PLC input and output indicators and record the addresses of the ones illuminated in the table of fi gure 105.

Inputs Outputs


M. Use the Sequence of Operation table for your station to determine the step where the cycle was interrupted. Record the step in the space provided and in the Troubleshooting Process Recording Chart.

Step: _____________________________________________________

The step will vary depending on the mechatronics station you are using. The table in fi gure 106 shows the steps where the process hanged.

Step Where Hang Occurred

Station Step

87-MS1 2

87-MS2 2

87-MS3 5

87-MS4 3

87-MS5 3

87-MS6 7

87-MS7 3

Figure 106. Fault 24 Halt Steps


117

N. Examine the next step in the Sequence of Operation table to determine which input has either not turned on or turned off to cause the cycle to hang. Record the input in the space provided and in the Troubleshooting Process Recording Chart.

Input: _____________________________________________________

You should have determined that on all stations except 87-MS4 an input did not illuminate to show an output had occurred.

Station 87-MS4 does not have a sensor to determine if the acrylic release opened. Troubleshoot the outputs for the sequence step determined in substep M.

O. Use the troubleshooting fl owcharts to determine why the input did not illuminate. Record your observation in the space provided and in the Troubleshooting Process Recording Chart.

Observation: _______________________________________________

You should have observed that while the output indicator for the devices was illuminated, the output did not actuate. This condition occurs when the output device fails or there is an open in the output circuit.

P. Click the Clear Fault button.

Q. Reset the station and test for proper operation.

R. Click the Exit button to exit the Single Fault Mode.

The Student Options window should be displayed.

S. Remove any valve components from the station except for knobs and screws from the 87-MS5 station.


118

9. Perform the following substeps to select a FaultPro template and enter the Random Fault Practice Mode for your mechatronics station.

The screen should appear similar to fi gure 107.

Figure 107. Student Menu Expanded to Show Skills


119

A. Click the Random Fault Mode button.

The dialog in fi gure 108 should be displayed.

Practice mode gives you an opportunity to practice troubleshooting randomly generated faults. Once you have practiced all of the faults in the skill template, you will use the Test mode to troubleshoot them again and be graded on your performance.

Figure 108. Random Fault Mode Options

B. Verify that Practice mode is selected and click the OK button.

The Practice Mode dialog should be displayed.

The station name should be grayed out in the Enter the suspected faulted station: fi eld.




A. Place an acrylic component at the input to the station.

If you are using the 87-MS3 Indexing Station, place the valve body with the thick side up.

B. Momentarily press the START pushbutton.

The station should hang at some point in its operation.

C. Observe the operation of the station and record your observations in the space provide.

Observation ________________________________________________


120

D. Observe the power supply and PLC status indicators. Record any abnormal indications in the space provided.

Abnormal Indicators: ________________________________________

You should have observed all status indicators were normal.

E. Record the station’s symptom in the Troubleshooting Process Recording Chart, as shown in fi gure 109.

The symptom will differ depending on the mechatronics station and the random fault that has been inserted.


Symptom Observed:


1

2

3

4

5

6

7

Remedy:



121

F. Observe the PLC input and output indicators and record the address of those that are illuminated in the table of fi gure 110.

Inputs Outputs


G. Compare the illuminated outputs with the outputs in the Sequence of Operation table to fi nd a match. Record the step where the outputs occur in the space provided and in the Troubleshooting Process Recording Chart.

Step ______________________________________________________

Remember, the symbol in the table indicates an output turned off during the step. However, it may be illuminated when the interruption occurs.

H. Compare the illuminated inputs with the inputs in the next step in the Sequence of Operation table to determine what input condition does not match the table.

I. Use the troubleshooting fl owcharts to troubleshoot the fault.

Once you think you have determined the fault, fi nd it in the FaultPro Available Faults for Selected Skill scrollbox.


122

J. Type the number of the suspected fault in the Enter suspected fault number: fi eld and click the Enter button, or press the Enter key on the keyboard.

The status fi eld will show the result of your selection.

If the answer is correct, the status fi eld will display Answer is Correct.

WARNING

Some faults, when cleared, will cause the mechatronics station to resume its cycle. Be alert for possible machine motion when clearing faults.

If the answer is incorrect, the status fi eld will display Answer is Not Correct.

If your answer is incorrect, you can:• Click the Try Again button to troubleshoot the current fault again.• Click the Clear button, and then the Next Fault button to continue to the next fault. • Click the Show Fault button to display the current fault.

A correct answer clears the fault from the mechatronics station and often the station will often complete the sequence of operation. Remove any valve components from the station and use the CYCLE SELECT switch to reset the station before enabling the next fault.

K. Click the Clear button, and then the Next Fault button to continue to the next fault.

FaultPro inserts another fault into the station (as long as faults remain in the template.) In some cases, you may need to press the mechatronics station’s OUTPUT POWER pushbutton to restore power to the outputs.

L. Repeat substeps A through J to troubleshoot all faults in the template.

In practice mode, FaultPro allows you to continue to practice. When all faults have been mastered, the status fi eld will display No faults left.

M. Click the Exit button to exit the Random Fault dialog.


N. If you feel comfortable troubleshooting this mechatronics skill, continue to Step 10 to enter the Random Fault Test Mode.

If not, repeat Step 10 for more practice.


123

11. Perform the following substeps to put random faults into the mechatronics station in the Test Mode.



B. Click the Test option then click the OK button to continue.

The Test Mode dialog should be displayed. The dialog is similar to the Practice Mode dialog except the time that you take to troubleshoot the fault and the number of tries that you take will be recorded. This informa-tion will be used in the assessment of your grade.



D. Use the procedure from the earlier steps to troubleshoot the faults.



F. Click the View Grades button to see your score. Record your grade for your personal records.

G. Click the Close button to exit the Grade View dialog.

The Student Menu should be displayed.

H. Click the Logout button to exit the Student Options window.


I. Click the Exit button to exit FaultPro Software. 12. Power down the mechatronics station and shut down the PC.


124

OBJECTIVE 11 DESCRIBE HOW TO TROUBLESHOOTMULTI-STATION FAULTS

The fi rst step in troubleshooting multi-station production line faults is deter-mining which station caused the fault. Isolating the failure to two possible stations is done by observing the product in each workstation. Generally, workstations following the failure continue to produce. The fi rst station that is not sending components to the next station is usually one of two stations where the failure has occurred. The other likely faulted station is the one that receives the part.

Once the two stations have been identifi ed, observation of the process is used to isolate the fault to one station.

Multi-station faults fall into two types: handshaking faults and station faults.

Handshaking Faults

Handshaking faults are failures in communications between the stations. A missing handshake usually stops the workstation at either the beginning or end of its cycle. For example, If Station A in fi gure 111 does not tell Station B it has a part ready, Station B cannot start its cycle. Likewise, if Station C cannot receive a part, Station B may not be able to continue its cycle until its completed part is gone from the station.

Figure 111. Handshaking Between Three Workstations

STATIONA

STATIONB

STATIONC

CONVEYOR CONVEYOR

INPLC OUT INPLC OUT INPLC OUT


125

Handshaking faults are suspected when one or more stations sit idle while those following it on the production line continue to operate normally. To isolate the station with a failure, go to the fi rst station that is not operating. For example, in fi gure 111 Station C is continuing to produce while Station B sits idle. Begin troubleshooting at Station B by examining its status indicators. If there are no abnormal indications, check the station’s incoming handshaking signals from the previous station.

Handshaking inputs and outputs are usually uniform for all stations and are found in the I/O diagram. Use the search utility to locate the handshaking instruc-tions then troubleshoot the inputs and outputs to determine the problem.

Station Faults

Station faults have been discussed and practiced in previous lessons and include failures of power supplies, input and output devices and their associated modules. Station faults most often occur after the cycle has started and are identifi ed by the station stopping in the middle of its cycle. For example, you can suspect a station fault if Station B in fi gure 111 stops somewhere other than at the beginning or end of its routine.

A station fault that mimics a handshaking fault occurs when a permissive input has failed. Permissives are conditions that must be met before the workstation can start. For example, consider a workstation that contains pneumatic and hydraulic actuators and a heating element. Before the machine can start, sensors must ener-gize to confi rm that both air and hydraulic pressures are present and the tempera-ture is in the appropriate range.


126

Permissives are usually programmed in series to control internal coils whose contacts may be used in several other networks. Network 1 in fi gure 112 shows several conditions that must be met before the workstation is ready to run. When all conditions are true, internal coil Ready to Start is enabled. A contact addressed as Ready to Start is the fi rst control element in Network 2. If any of the permissive conditions become false, the Blend Pump will not start or stop if it is running.

Figure 112. Programming Permissives

Permissives are generally programmed near the beginning of the logic program and when faulted, usually prevent the workstation from starting. However, a permissive fault can stop the workstation in mid cycle. The same troubleshooting techniques used for other inputs and outputs are used to troubleshoot them.


127

SKILL 8 TROUBLESHOOT HANDSHAKING AND PERMISSIVE FAULTS

Procedure Overview

In this procedure, you will connect multiple mechatronics stations together and troubleshoot handshaking faults and permissive faults. First, you will manually insert faults to gain experience troubleshooting handshaking faults. Then you will troubleshoot randomly generated faults.

1. Locate the mechatronics system. 2. Figure 113 shows the nine station combinations considered complete systems. Keep in mind that stations can only be connected to the stations listed next to

them in the chart.

STATION COMBINATIONS

1 2 3 4 5 6 7

1 Pick and Place Feeding

Gauging


Gauging Parts Storage


Gauging Indexing


Gauging Indexing Parts Storage


Gauging Indexing Assembly

6 Pick and PlaceFeeding

Gauging Sorting andQueuing

Assembly


Gauging Indexing Assembly Parts Storage


Gauging Indexing Sorting and Queuing

Assembly



Assembly Parts Storage



Assembly Torquing Parts Storage

Figure 113. Station Combinations

3. Select two or more stations to connect and connect them together with electrical power, air, and communications.

4. Review fi gure 114 to see if you need to make any mechanical adjustments for your station combinations.

The seven stations typically are mechanically adjusted to work with a specifi c upstream or downstream station. If you run the stations in any order besides that listed in row 9 of fi gure 113, then some mechanical adjustments may need to be made in order for the parts to transfer smoothly.


128

FIRSTSTATION

SECONDSTATION ADJUSTMENTS REQUIRED

Gauging Parts Storage The power slide will have to be loosened and moved toward the Gauging station so that the grippers can pick up the part. Then, once that is set, the location tabs on top of the slide will have to be readjusted so that the gripper stops in line with the storage bays.

Gauging Sorting andQueuing

The traverse will have to be loosened and moved away from the Sorting and Queuing station about 1/2 inch to prevent the conveyor from rubbing on the traverse frame. The traverse axis will then have to be fastened down tightly again.

Indexing Assembly The robot pickup location will have to be re-taught.

Indexing Parts Storage Some adjustment to the power slide may be necessary so the gripper can pick up off the indexing table. The transfer cylinder extend on the indexing station will need to be disabled so the Part Storage gripper can pick the part up.

Figure 114. Station Adjustments

NOTE

Be sure to use a plastic parts bin where needed to catch parts.

NOTE

If you are using Station Combination #6, the valve bodies must be inserted into the parts feeder in the correct orientation for the Assembly station. This is because there is no Indexing station to reorient the part.

5. Perform the following substeps to prepare the mechatronics stations for fault insertion.

A. Verify that each station has an 87-FS Fault Box installed.

B. Connect a USB communications cable from a USB port on the PC to the PREVIOUS STATION/PC socket on the fi rst station.

C. Connect a USB communications cable from the Next Station port on the fi rst station to the PREVIOUS STATION/PC socket on the next station. Connect all stations together in the same manner.

Use a second USB cable if more than three stations are connected together.


129






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7. Perform the following substeps to power up each station.


B. Turn the station’s ON/OFF switch to the ON position 8. Perform the following substeps to download programs to the mechatronics

stations.

A. Start and log in to the PC.


C. Open the program for the station as shown in the table of fi gure 116.

Station Project

87-MS1 Feeder

87-MS2 Gauging

87-MS3 Indexing



87-MS6 Torquing




130

D. Download the program to the PLC.

E. Place the PLC in the RUN mode.

F. Download the program to each PLC in the connected stations. 9. Perform the following substeps to verify correct operation of the mechatronics

stations.

A. Remove any valve components from all stations except the knobs, screws, and spools in the 87-MS5 station.

B. Move the CYCLE SELECT switch to the RESET position then to AUTO for each station.

C. Place an acrylic component at the input to the fi rst station.

D. Momentarily press the START pushbutton.

The station should execute its program then pass its component to the next station.

Contact your instruction if the sequence is not correct. 10. Obtain copies of the Troubleshooting Flowcharts, Sequence of Operation

tables, and the Troubleshooting Process Recording Chart from your instructor. 11. Open the FaultPro software and log in using your student ID and password. The software should open to the Student Options Window.


131

12. Perform the following substeps to insert and troubleshoot a handshaking fault into a mechatronics station.

Mechatronics stations communicate on four discrete outputs hardwired to four discrete inputs on other stations. The four outputs and inputs are:

• Ready to PS (Q4.1) - Tells previous station the sender is ready to receive a part. Connects to input I0.6, Ready from NS.• Present to PS (Q4.2) - Tells previous station the sender’s output power is on. Connects to input I0.7, Present from NS.• Go to NS (Q4.3) - Tells next station sender has a part ready to pick up. Connects to input I0.4, Go from NS.• Present to NS -(Q4.4) - Tells next station sender’s output power on. In some stations, the Present to NS tells the station the sender is clear and it is safe to move the part. Connects to input I0.5, Ready from NS.

Figure 117. Handshaking Connections

The table in fi gure 118 shows the connections between the sending and receiving stations.

HANDSHAKING CONNECTION

Sending Station From To Receiving Station

Ready to PS Q4.1 I0.6 Ready from NS

Present to PS Q4.2 I0.7 Present from NS

Go to NS Q4.3 I0.4 Go from PS

Present to NS Q4.5 I0.5 Present from NS

Figure 118. Handshaking Connections

READY TO PS

PRESENT TO PS

I0.4

I0.5

I0.6

I0.7

Q4.1

Q4.2

Q4.3

Q4.4

STATION A

I0.4

I0.5

I0.6

I0.7

Q4.1

Q4.2

Q4.3

Q4.4

STATION B

GO TO NS

PRESENT TO NS

READY FROM NS

PRESENT FROM NS

GO FROM PS

PRESENT FROM PS

GO TO NS

PRESENT TO NS

READY TO PS

PRESENT TO PS


132


B. Open the LAP 2 option.

C. Select the Skill 8 option.

D. From the Student Options window, click the Single Fault Mode button.

The Single Fault Mode window should open.

E. Select the mechatronics station to receive the fault from the drop list.

Do not select the fi rst station of those connected together as the fault inter-rupts handshaking from the previous station.

F. Type 3 in the Enter Fault: fi eld and click Enter.

The status fi eld should show Fault 3 is Active.

G. Place an acrylic valve component at the input of the fi rst station and momentarily press the START pushbutton. Observe the stations and record your observation in the space provided and in the Troubleshooting Process Recording Chart, such as the one shown in fi gure 119.

Observation ________________________________________________


Symptom Observed:


1

2

3

4

5

6

7

Remedy:


You should have observed one or more of the mechatronics stations failed to end or start its cycle.

H. Observe the PLC and power supply status indicators and record any abnormal indications.

Abnormal indications ________________________________________

You should have recorded all status indications are normal.


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I. Observe the stations to determine at which ones the line stoppage occurred. Record the station numbers in the space provided and in the Troubleshooting Process Recording Chart.

Stations: ___________________________________________________

Your results will vary depending on the stations connected and the station that received the fault.

The failure could be in the receiving station, the sending station or the communications link between the two stations. The following substeps will isolate the failure to one station.

J. Observe the handshaking input and output indicators on the receiving station. Record your observation in the space provided and in the Trouble-shooting Process Recording Chart.

Go from PS (I0.4) ____________________________________(On/Off)

Present from PS (I0.5) ________________________________(On/Off)

Ready to PS (Q4.1) ___________________________________(On/Off)

Present to PS (Q4.2) __________________________________(On/Off)

You should have observed the Go from PS input was not illuminated and the Present from PS was on. The Ready to PS and Present to PS output indicators were illuminated.

The indicators show the station is not receiving the Go signal from the sending station. The failure could be in the receiving station, the sending station or the wiring between the stations.

The following substeps will isolate the problem

K. Observe the handshaking input and output indicators on the sending station. Record your observation in the space provided and in the Trouble-shooting Process Recording Chart.

Ready from NS (I0.6) _________________________________(On/Off)

Present from NS (I0.7) ________________________________(On/Off)

Go to NS (Q4.3) _____________________________________(On/Off)

Present to NS (Q4.4) __________________________________(On/Off)

You should have observed that all indicators were illuminated.

The indicators show the sending station is issuing the Go signal but it is not arriving at the receiving station. The problem is in either the receiving station or the wiring between stations.


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L. Measure the voltage on the Go from PS (I0.4) input terminal on top of the receiving station. Record your measurement in the space provided and in the Troubleshooting Process Recording Chart.

Input I0.4 ____________________________________________ (Volts)

You should have measured 24 VDC.

This eliminates the wiring as a source of the failure.

M. Measure the voltage on the Go from PS (I0.4) terminal of the receiving station input module. Record your measurement in the space provided and in the Troubleshooting Process Recording Chart.

Input I0.4 ____________________________________________ (Volts)

You should have measured 0 VDC.

This isolates the problem to the wiring in the receiving station.

Fault 3 emulates a Go from PS failure in the receiving station.

N. Click the FaultPro Clear Fault button.

The fault is cleared and the process may continue, depending on the station.

O. Reset both stations and test for proper operation.

Normal operation should be restored. 13. Perform the following substeps to troubleshoot a handshaking fault in a

mechatronics station.

A. Select a mechatronics station to receive the fault from the Single Fault Mode drop list.

Do not select the last station of those connected together.

B. Type 22 in the Enter Fault: fi eld and click Enter.

C. Place an acrylic valve component at the input of the fi rst station and momentarily press the START pushbutton. Observe the stations and record your observation in the space provided and in the Troubleshooting Process Recording Chart.

Observation ________________________________________________

You should have observed that one or more of the mechatronics stations failed to end or start its cycle.

D. Record the station or stations that did not operate correctly. Also enter the station names in the Troubleshooting Process Recording Chart.

Stopped stations ____________________________________________

Your observation will vary with the stations connected and the fault.

E. Observe the PLC and power supply indicators and record any abnormal indications.


You should have recorded all status indicators were normal.


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F. Observe the handshaking input and output indicators on the receiving station. Record your observation in the space provided and in the Trouble-shooting Process Recording Chart.

Go from PS (I0.4) ____________________________________(On/Off)

Present from PS (I0.5) ________________________________(On/Off)

Ready to PS (Q4.1) ___________________________________(On/Off)

Present to PS (Q4.2) __________________________________(On/Off)

You should have observed that the Go from PS input indicator was not illuminated and the Present from PS indicator was on. You should also have observed that both the Ready to PS and Present to PS output indica-tors were illuminated.

G. Observe the handshaking input and output indicators on the sending station. Record your observation in the space provided and in the Trouble-shooting Process Recording Chart.

Ready from NS (I0.6) _________________________________(On/Off)

Present from NS (I0.7) ________________________________(On/Off)

Go to NS (Q4.3) _____________________________________(On/Off)

Present to NS (Q4.4) __________________________________(On/Off)

You should have observed that both the Ready from NS and Present from NS input indicators were illuminated. You should also have observed that both the Go to NS and the Present to NS output indicators were illuminated.

The sending station is issuing the Go command but it is not arriving at the receiving station. A failure has occurred in one of the stations or the wiring between them. The following substeps will isolate the failure to one station.

H. Measure the voltage at the Go from PS (I0.4) input terminal block on the top of the receiving station. Record your measurement in the space provided and in the Troubleshooting Process Recording Chart.

Input I0.4 ___________________________________________ (Volts)

You should have recorded 0 VDC. This is the input to the station from the previous station. By measuring 0 VDC you have determined the failure is either in the sending station or the wiring between the two stations.


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I. Measure the voltage at Go to NS (Q4.3) output terminal block on the top of the sending station. Record your measurement in the space provided and in the Troubleshooting Process Recording Chart.

Output terminal Q4.3 __________________________________ (Volts)

You should have measured 0 VDC. Although the output indicator for Q4.3 is illuminated the output voltage is not present at the terminal block that connects the station to the next station. The failure could be in the output module or the wiring between the output module and the terminal block.

J. Measure the voltage for the Go to NS (Q4.3) at the module output terminal. Record your measurement in the space provided and the Troubleshooting Process Recording Chart.

Output module Q4.3 ___________________________________ (Volts)

You should have measured 24 VDC. This indicates the failure is in the wiring between the output module and the terminal block.

Fault 22 simulates a failure of the Go to NS handshake in the sending station.

K. Click the Fault Pro Clear Fault button.

The fault is cleared and the process may continue.

L. Reset both stations and test for proper operation.

Normal operation should be restored. 14. Perform the following substeps to insert and troubleshoot a permissive fault

in a mechatronics station.

A. Select a mechatronics station to receive the fault from the Single Fault Mode drop list.

B. Type 2 in the Enter Fault: fi eld and click Enter.

C. Place an acrylic valve component at the input of the fi rst station and momentarily press the START pushbutton. Observe the stations and record your observation in the space provided and in the Troubleshooting Process Recording Chart.

Observation ________________________________________________

You should have observed the green pilot light fl ashing on the mecha-tronics station that received the fault. You should also have observed the station did not start its cycle.

D. Observe the PLC and power supply indicators and record any abnormal indications.


You should have recorded all status indicators were normal.


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E. Use the Sequence of Operation table for the station to determine the step where the stoppage occurred. Record the step in the space provided and in the Troubleshooting Process Recording Chart.

Step ______________________________________________________

You should have observed the hang occurred in step 0.

F. Compare the inputs in step 0 of the table with those on the PLC and record any discrepancies in the space provided and in the Troubleshooting Process Recording Chart.

Discrepancies ______________________________________________

You should have recorded that the indicator input I0.3 was not illuminated.

Fault 2 opens I0.3, the Output Power On permissive, which is one of the conditions to set the “General Start Cond. Met” internal coil. An open Output Power On contact also sets the fault that turns on the fl ashing green pilot light.

Permissives are usually programmed near the beginning of the ladder logic to prevent outputs from energizing before permissives have been checked.

G. Go online to the faulted station and enable the Monitor to observe instruc-tion status.

H. Scroll down until you locate a network that appears to be a series of pre-start conditions. Record the output tag in the space provided and in the Troubleshooting Process Recording Chart.

Output tag _________________________________________________

You should have recorded M0.x, General Start Cond. Met. The output is enabled when all of the instructions in the rung are true. M0.x is an internal coil not associated with a real world output.

A contact addressed as M0.x begins the following network where addi-tional conditions are monitored. If all conditions are true in both rungs, internal output M0.y, Station Ready, is enabled.

I. Examine the rung for false indication on the instructions. Record the address of any false instructions in the space provided and in the Trouble-shooting Process Recording Chart.

False instructions ___________________________________________

You should have recorded the N.O. instruction with address I0.3, Output Power On, was false.

The output of the MCR circuit that provides control power to the output module is connected to input I0.3 station to prevent the station from oper-ating unless the modules have control power.

The Output Power On input is also used to set the Present to PS and Present to NS handshaking outputs.


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J. Using the techniques learned earlier, troubleshoot the input. Record your results in the space below and in the Troubleshooting Process Recording Chart.

Result ____________________________________________________

You should have recorded that the MCR circuit was enabled but the voltage was not measured at the input module terminal.

Fault 2 emulates an Output Power On failure.

K. Click the FaultPro Clear Fault button to clear the fault.

L. Reset the station and test for proper operation.

Normal operation should be restored.

M. Repeat step 14 for the other mechatronics stations connected together. 15. Perform the following substeps to select a FaultPro template, enter the

Random Fault Practice Mode, and insert handshaking and permissive faults into the mechatronics stations for troubleshooting.

The random fault mode will insert a fault in a station randomly selected by FaultPro software.


B. Click the plus sign to the left of the LAP 2 option to expand it.

The skills for LAP 2 should be displayed.

D. Click the icon for the Skill 8 option.

E. Click the Random Fault Mode button.

F. Verify that Practice mode is highlighted and click OK.

G. Click the FaultPro Start button to insert the fi rst fault.



A. Place an acrylic component at the input to the fi rst station.

If you are using the 87-MS3 Indexing station position the part with the thick side up.

B. Momentarily press the mechatronics station’s START pushbutton.

Two stations should hang at some point in their operation.

C. Observe the PLC and power supply status indicators and record any abnormal indications.


You should have recorded all status indications are normal.


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D. Record the affected station’s numbers and symptom in the Trouble-shooting Process Recording Chart.

E. Use the procedure from steps 12 through 14 to troubleshoot the fault. Identify the station where the fault occurred and the type of fault, (Go to NS, Go From PS, or permissive) in the space provided and in the Trouble-shooting Process Recording Chart.

Faulted station ______________________________________________

Fault type _________________________________________________

The faulted station will vary with the mechatronics stations connected.

F. Locate the fault number in the FaultPro Active Faults for Selected Work-station scrollbox and enter it in the space provided and in the Trouble-shooting Progress Recording Chart.

Suspected fault: _____________________________________________

Your suspected fault will vary depending on the mechatronics stations connected and the random fault entered.

G. Using the drop arrow at the right of the Enter the suspected faulted station: fi eld, select the station you entered in substep E from the list of attached stations.

H. Type the number of the suspected fault in the Enter suspected fault number: fi eld and click the Enter button, or press the Enter key on the keyboard.

The status fi eld will show the result of your selection.

If you selected the wrong station, the status fi eld will display the message The input fault is not valid for this station. Try again.

If your selected fault is incorrect, the status fi eld will display Answer is not correct.

If either selection was wrong, click the Try Again button to troubleshoot the fault again.

I. If your answer is correct, reset the station and remove all components from the station except the knobs and screws from the 87-MS5 station.

J. Click the Clear button, and then the Next Fault button.

K. Continue troubleshooting until you have completed all of the faults in the template.

When all faults have been mastered, the status fi eld will display No faults left.

L. Click the Exit button to exit the Random Fault dialog.


M. If you feel comfortable troubleshooting this mechatronics skill, continue to Step 17 to enter the Random Fault Test Mode.

If you would like more practice, repeat Step 16.


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17. Perform the following substeps to induce random handshaking and permissive faults into the mechatronics station in the Test Mode and troubleshoot the faults.



B. Click Test then click OK to continue.

The Test Mode dialog should be displayed.

The dialog is similar to the Practice Mode dialog except the time that you take to troubleshoot the faults and the number of tries that you make will be recorded. This information will be used in the assessment of your grade.



D. Use the procedure from Steps 16 through 17 to determine the symptom and troubleshoot the faults.

Use only acrylic valve bodies and if you are using the 87-MS3 Indexing station position the part with the thick side up.

Remember to reset the station and remove all valve components from the station except for the knobs and screws in the 87-MS5 station before clicking the Next Fault button.




G. Click the Close button to exit the Grade View dialog.

The Student Options window should be displayed. 18. Continue to the next skill.


141

SKILL 9 TROUBLESHOOT MULTI-STATION FAULTS

Procedure Overview

In this procedure, you will troubleshoot randomly generated faults in random mechatronics stations. You will fi rst determine in which station the fault occurred and then troubleshoot the fault that caused the process to hang. You will gain experience in isolating and resolving faults that occur on a typical production line.

1. Perform the following substeps to prepare the mechatronics stations for operation.

A. Verify that the mechatronics stations are connected together as in the previous skill.

B. Verify that each station has an 87-FS Fault Box is installed and is connected to the station.

C. Verify that all stations are connected on the USB network and the network is connected to the PC.

Use a second USB cable if more than three stations are connected together.

D. Verify that the mechatronics stations are powered up with electricity and air.

E. Verify that the programs from the previous skill are still installed in the PLCs and that they are in the RUN mode.

F. Verify that all stations operate properly.

G. Verify that the FaultPro Student Options window is displayed.

H. Remove all valve components from the stations except the knobs, screws, and spools from the 87-MS5 station.


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3. Perform the following substeps to select a FaultPro template and enter the Random Fault Practice Mode for the mechatronics stations.

A. From the Student Options window, open the Class folder, if required.

B. Click the plus sign to the left of the LAP 2 option to expand it.

The skills for LAP 2 should be displayed.

C. Click the icon for the Skill 9 option.

D. Click the Random Fault Mode button.

E. Verify that Practice mode is highlighted and click OK.

F. Click the FaultPro Start button to insert the fi rst fault.

A fault has been inserted into one of the mechatronics stations. The soft-ware prompts you to enter the fault number (a blinking cursor appears in the Enter the suspected fault number: fi eld.)

4. Perform the following substeps to troubleshoot multi-station faults.

A. Place an acrylic component at the input to the fi rst station.

If you are using the 87-MS3 Indexing station, position the part with the thick side up.

B. Momentarily press the mechatronics station’s START pushbutton.

Two stations should hang at some point in their operation.

C. Use the skills you have gained in previous lessons to determine the faulted station and the suspected fault number.

D. Use the procedure from the previous skill to enter the suspected faulted station and the suspected fault number.

E. When you have completed a fault, remove all valve components from the station except for the knobs, screws, and spools in the 87-MS5 station.

F. Click the Clear button, and then the Next Fault button.

G. Continue troubleshooting until all faults have been completed.


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H. Click the Exit button.

If you feel comfortable with the practice faults, continue to step 5. If you want more practice, repeat the faults in the practice mode.

Remember to reset the station and remove all valve components from the station except for the knobs and screws in the 87-MS5 station before clicking the Next Fault button.

5. Perform the following substeps to troubleshoot multi-station faults in the Test mode.


B. Click Test to select the test mode then click OK.


D. Perform the substeps in step 4 to troubleshoot faults in the Test mode.

Use only acrylic valve bodies and if you are using the 87-MS3 Indexing station, position the part with the thick side up.

Remember to reset the station, remove all valve components from the station except for the knobs, screws, and spools in the 87-MS5 station, and to place an acrylic spool at the entry of the station before clicking the Next Fault button.

E. Continue troubleshooting faults until the message No faults left is displayed.


G. lick the Close button to exit the View Grade dialog.


H. Click the Logout button to exit the Student Options window.


I. Click the Exit button to exit FaultPro Software. 6. Power down the mechatronics station and shut down the PC. 7. Ask your instructor if you should do some extended troubleshooting. If so,

your instructor will give you instructions on how to proceed.


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1. A(n) ________________ table identifi es the inputs and outputs that are turned on and off for each step a workstation performs to produce a product.

2. ____________ in the table represent the status indicators on the PLC’s input and output modules.

3. A table can be used to determine the ___________ where the process hanged.

4. The fi rst step in troubleshooting multi-station faults is determining which ______________ caused the fault.

5. A missing ____________ usually stops the workstation at either the beginning or end of its cycle.

6. ________________ are conditions that must be met before the workstation can start.

7. A false permissive usually keeps the workstation from _________ and can stop it in mid-cycle.

mechatronics troubleshooting learning activity packet …€¦ · learning activity packet...

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