automation 21
TRANSCRIPT
Automation:
AUTOMATION:
Automation is the use of control systems such as computers to control industrial machinery and processes, replacing human operators. In the scope of industrialization, it is a step beyond mechanization. Whereas mechanization provided human operators with machinery to assist them with the physical requirements of work, automation greatly reduces the need for human sensory and mental requirements as well.
ADVANTAGES OF AUTOMATION:
The purpose of automation has shifted from increasing productivity and reducing costs, to broader issues, such as increasing quality and flexibility in the manufacturing process.
Automation is now often applied primarily to increase quality in the manufacturing process, where automation can increase quality substantially.
For example, automobile and truck pistons used to be installed into engines manually. This is rapidly being transitioned to automated machine installation, because the error rate for manual installment was around 1-1.5%, but has been reduced to 0.00001% with automation.
Hazardous operations, such as oil refining, the manufacturing of industrial chemicals, and all forms of metal working, were always early contenders for automation.
Application of AutomationPower generation
TRANSMISSION AND DISTRIBUTION:
Oil and gas industries
Process industries
Building automation
HISTORY OF AUTOMATION
MANUAL CONTROL
HARDWIRED CONTROL:Prior to PLCs, many of these control tasks were solved with contactor or relay controls. This is often referred to as hard-wired control. Circuit diagrams had to be designed, electrical components specified and installed, and wiring lists created. Electricians would then wire the components necessary to perform a specific task. If an error was made the wires had to be reconnected correctly. A change in function or system expansion required extensive component changes and rewiring.
DRAWBACKS:
Bulky and complex wiring.
Difficult to change the logic.
Unreliable.
RELAY :
RELAY LOGIC AND GATE:
ELECTRONICS CONTROL
Logic gates and Electronic Circuits are used
Ease of programming
Ease of maintenance
Drawbacks:
Difficult to Troubleshoot while Change the Logic of the Process
Difficult to expand
Not suitable for industrial conditions
PROGRAMMABLE LOGICAL CONTORLWhat is a Programmable Logic Controller PLC?
PLC is a device, which is used to control a machine or process as per the human control sequence. A PLC monitors inputs, makes decisions based on its program, and controls outputs to automate a process or machine.
Advantages Smaller physical size than hard-wire solutions
Easier and faster to make changes
PLCs have integrated diagnostics and override functions
Diagnostics are centrally available
Applications can be immediately documented
Applications can be duplicated faster and less expensively
PROCESSOR MEMORY ORGANIZATION
The memory of a PLC is organized by types.
The memory space can be divided into two broad categories:
Program and Data Memory:
Advanced ladder logic functins allow controllers to perform calculatins, make decisions and do other complex tasks. Timers and counters are examples of ladder logic functions. They are more comples than basic inputs contacts and output coils and relay heavily upon data stored in the memory of the PLC.
PROGRAM FILES:
The user program will account for most of the memory of a PLC system.
Program files contain the logic controlling machine operation.
This logic consistes of instructions that are programmed in a ladder logic format.
DATA FILES:
The data file protion of memory stores input and output status, processor status, the status of various bits and numerical data.
INPUT TABLE FILE OPERATION:
Processor continually reads current input status and updates input image table file.
OUTPUT TABLE FILE OPERATION:
Processor continually activates or deactivates ouput status according to output image table file status
PROGRAM SCAN:
During each operating cycle, the processor reads all inputs, takes these values, and energizes or de-energizes the outputs according to the user program. This process is known as a scan. Because the inputs can change at any time, the PLC must carry on this process continuously.
1. I/O scan records status data of input devices. Energizes output devices that have their associated status bits set to ON (1)
2. Program scan instruction are executed sequentially.
SCAN PROCESS:
The scan time indicates how fast the controller can react to changes in inputs. Scan times vary with computer model and program content, and length. If a controller has to react to an input signal that changes states twice during the scan time, it is possible that the PLC will never be able to detect this change.
When the inputs is closed, the input module senses a voltage and an ON condition (1) is entered into the input table bit 0012.
During the program scan the processor sets instructins 0012 and 506 to ON(1).
The processor turns light output 506 ON during the next I/O scan.
KEYENCE
ADDRESS:
INPUTS:
0000to0015
0100to0115
0200to0215
0300to0315
0400to0415
OUTPUTS:
0500 to0515
0600to0615
0700to0715
0800to0815
0900to0915
INTERNAL MEMORY BIT:
1000to1015
Upto
1900to1915
TIMERS:
TMR space #(0.1sec)
TMH space #(0.01sec)
TMS space #(0.001sec)
COUNTERS:
Up counter: C space #space
Up/Dwn counter: Cspace#
PROCEDURE FOR PROGRAMMING:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1601. Edit command/Lable
02. Edit line command
03. Show/Hide command
04. Jump to specified line/step
05. Find
06. Replace operand
07. Usage information
08. Edit list
09. compail
010. Show compilation error
011. Transfer to PLC
012. Read from PLC
013. Plc monitor
014. Simulator
015. Display mode
016. Description of operation
1 2 3 4 5 6 7 8 9 10
01. N.O. contact OR input
02. NC contact OR input
03. NO contact input
04. NC contact input
05. Output coil
06. NC output coil
07. Input vertical connection line
08. Delete vertical connection line
09. Input Horizantal connection line
010. Delete Horizantal connection line
BASIC PROGRAMMES:
--| |--
NORMALY OPEN CONTACT
--| / |--
NORMALY CLOSED CONTACT
--( )--
COIL
EX: 1
When the switch (SW) is ON, the LOAD should ON (Rung 0001)When the switch (SW) is OFF, the LOAD should ON (Rung 0002
Note:The all programming sequence should complete with END AND ENDH.
LADDER LOGICS FOR DIGITAL GATES:
OR :
I1I2L
000
011
101
111
AND:
I1I2L
000
010
100
111
NOR:
I1I2L
001
010
100
110
NAND:
I1I2L
001
011
101
110
EX-OR:
EX-NOR:I1I2L
001
011
101
110
I1I2L
001
011
101
110
SWITCH CONTACTS:
EX 1:SW1= 0000, SW2= 0001,LD1 = 500,LD2 = 501
SW1SW2LD1LD2
1010
1101
EX 2:
SW1SW2SW3LD1LD2LD3
011100
100010
111001