Daniel Adams-Zarate & Levi Martin

Project Proposal Organic Chocolate Ltd

September 27

2011Industrial Automation Ltd

The Challenge

Organic Chocolate Ltd has recently updated most of their plant to include communication and remote input capability, and now wish to automate the plant using ABB PLC.

Unfortunately a contractual issue has stopped the original contractor from finishing the work and his lawyers have instructed him to hold back the design and wiring drawings.

Industrial Automation’s challenge is to complete the set up on their new automated chocolate manufacturing line.

Brief

The recipe for Organic Chocolate Ltd is a mixture of: 100kg of cocoa powder, 1.5kg of emulsifier and 50kg of palm oil.

The Cocoa powder is added to the mixing vessel by operating the hopper slide ram until the weight of the vessel has reached 100kg.

The hopper slide ram closes, the mixer motor is started and the palm oil valve is opened until 50kg is added to the mix. The palm oil valve is closed.

Emulsifier valve opened 1 minute later to allow 1.5kg of emulsifier to be added. Emulsifier valve closes.

The mixer must continue for an additional 7 minutes 35 seconds. The mixer is then lifted out of the vessel and the process stops for 20 minutes to de-aerate.

The #1 drain valve is then opened to allow the mixture to drain onto the chocolate molding machine; a signal is sent to the chocolate molding machine to start operating when the vessel is empty, and the cleaning cycle begins.

The cleaning cycle requires that the mixer is lowered and started rotating; 200L of water added to the vessel and allowed to be stirred for 5 minutes.

The #2 drain valve is opened until the vessel is empty. The drain valve is closed and the cycle is reset.

The process is to be displayed as visualization available to production staff so that they see the status of production at any time.

Cocoa Powder Silo500kg Capacity

Hopper Slide Ram

Mixer Lift Ram

Mixer Motor

Palm Oil Reservoir Emulsifier

Water Mains Pipe

Mixing Vessel

Drain 2 Drain 1

250l 20l

1

108

6

12 13 14

11

15

2

16

3 4

7

9

5

17

Siren Alarm

Legend:

1 Cocoa Level sensor 2 Strain Gauge

3 Palm Oil Ultrasonic Sensor4 Emulsifier Ultrasonic

Sensor5 VSD (Motor Speed)

6 Hall Effect Sensor (Motor Speed)

7 Upper Ram Limit Switch8 Mid Ram Limit Switch

9 Lower Ram Limit Switch10 Hopper Slide Ram (Cocoa

Powder)11 Lift Ram

12 Palm Oil Valve13 Emulsifier Valve

14 Water Valve15 Drain Valve 1 (Mould

Machine)16 Drain Valve 2 (Waste)

17 Siren Alarm/GSM Alarm18 Safety Guard Sensor

18

Fig 1: Mixer Schematic

Technical Solution

Features:

Speed Control and Direction to mixer motor Variable speed for cleaning cycle Time-out for filling process (alarm if filling takes longer then preset time) Variable input for total batch weight (percentage based) Human Machine Interface (HMI) for operating staff Isolation On/Off switch (Process is not compromised) Emergency stop

Process:

The Main Process is illustrated below; it shows the whole process in sub routines. This would be similar to how it would look like in CFC, except there would be no arrows and the boxes would be labelled in chronological order.

Main Process

Auto Start Process

Check Status of operation

Add ingredients and start mixing process

De-aerate process

Drain process

Send signal to moulding machine

Cleaning cycle

The Auto start sub routine is shown below. It would also be programmed in CFC with complex parts called up in structured text or instruction list.

Auto start process

Home Screen

Chooses automatic settings

Check status opperation

Description is included below.

(From restart)

1) Welcome Screen

2) All timers and counters and temporarily variables are reset

Auto) User will be directed to a new screen which will allow the user to choose the settings they want.

Settings: Amount of cycles, Manual confirmation after cycle, problem notification, motor speed, motor direction, cleaning cycle mode, net batch mix (percentage based), Alarm time outs, empty level, and HMI activation settings will only be applied if they fall within the limits of the code, which is pre-defined by the programmer.

(From cycle)

3) Reset all temporary counters and timers

4) Chosen settings will then be applied and program will move to sub routine "check status of operation"

The Check status of operation is shown below. It would also be programmed in CFC with complex parts called up in structured text or instruction list.

Check status of opperation

Check Status of operation

Every process ideal Display problems

Problem Fixed

Home screen and problem logged

Add ingredients and start mixing

Description is included below.

Check Status of operation

1) Diagnostic window pops up on HMI which will display the process2) Will check status of Safety interlocks, switches, strain gauge with-in limits2b) If there is a problem with any of these functions, problem LED will be lit and fault shown on HMI, Process is then paused2C) Operator will then have to acknowledge problem, and see if they can fix the problem

If problem can be fixed2d) Operator will press confirm then program will jump back to 2 and check all the status’s' again from the beginning

If problem cannot be fixed2e) operator will press the shutdown function, the problem will be logged and the Design Engineer will be sent an automatic message with the problem log. Operator will then be able to lock out the machine

3) Will check levels of Cocoa powder, palm oil and Emulsifier

If problem can be fixed3b) Operator will press confirm then program will jump back to 3 and check all the status’s' again from the beginning

If problem cannot be fixed easily3c) operator will press the shutdown function, the problem will be logged and the problem can be sorted while offline

4) Continues to next subroutine "add ingredients and start mixing"

The Add ingredients subroutine is shown below. It would also be programmed in CFC with complex parts called up in structured text or instruction list.

Add ingredients

Add ingredients and start mixing

Add coca powder

Start mixing

Palm oil and Emulsifier added

Finish Mix

De-aerate process

Description is included below.

Add ingredients and start mixing

1) Cocoa powder slide ram is opened and cocoa is added

2) Strain gauge measures amount of cocoa required and closes ram at required amount

2b) If strain gauge measures increase in weight above the required amount and keeps increasing, problem LED is lit and alarm is sound. Problem is logged and process is STOPPED and reset

2c) If strain gauge measures increase in weight above the required amount and stops increasing, problem LED is lit and dependent on mode, Problem will be solved.

2d) If strain gauge measures decreasing weight or no weight gain during filling then problem LED is lit and alarm is sound, and problem is Logged and process STOPED and reset.

2e) if strain gauge measures underweight after ram is closed then it will slowly increase weight by opening hopper slide ram until the correct weight is achieved.

3) Start mixing at chosen motor speed.

4) Add palm oil has been added to chosen amount (still mixing)

4b) If strain gauge measures increase in weight above the required amount and keeps increasing, problem LED is lit and alarm is sound. Problem is logged and process is STOPPED and reset

4c) If strain gauge measures increase in weight above the required amount and stops increasing, problem LED is lit and dependent on mode, Problem will be solved.

4d) If strain gauge measures decreasing weight or no weight gain during filling then problem LED is lit and alarm is sound, and problem is logged and process STOPED and reset

4e) If strain gauge measures underweight after the valve is closed then it will slowly increase weight by opening the valve until the correct weight is achieved

5) Once correct amount of palm oil has been added mixer starts timer 1 (1 min) (still mixing)

6) Once timer 1 expires emulsifier is added to required amount

6b) If strain gauge measures increase in weight above the required amount and keeps increasing, problem LED is lit and alarm is sound. Problem is logged and process is STOPPED and reset

6c) If strain gauge measures increase in weight above the required amount and stops increasing, problem LED is lit and dependent on mode, problem will be solved.

6d) If strain gauge measures decreasing weight or no weight gain during filling then problem LED is lit and alarm is sound, and problem is Logged and process STOPED and reset

6e) If strain gauge measures underweight after the valve is closed then it will slowly increase weight by opening the valve until the correct weight is achieved

7) Once correct amount of emulsifier is added timer 2 is started (7 min 35 sec) (still mixing)

8) Once timer 2 is done, start sub routine "De-aerate process"

Note; If motor fault or mixer lift ram occurs will operating in this sequence then process is stopped and alarm is sent and problem is logged, problem could then be resolved and process resumed or process could be shutdown.

The De-aerate process is shown below. It would also be programmed in CFC with complex parts called up in structured text or instruction list.

De-aerate process

De-aerate process

Mixer lifted out

Wait 20 minutes

Drain process

Description is included below.

De-aerate Process

1) The mixer is lifted halfway and the motor is spun to remove excess mix off its blades. Then mixer is lifted all the way out

2) Timer 3 is then started (20 min)

3) Once timer 3 is done then "Drain process" subroutine is called

Note; If the mixer lift ram fails, then process is stopped and alarm is sound, problem is logged. If problem can be fixed process, will be resumed if not process will be reset and shutdown.

The Draining process is shown below. It would also be programmed in CFC with complex parts called up in structured text or instruction list.

Draining process

Drain process

Drain valve is opened

Mixture drained

Cleaning cycle

Signal sent to moulding machine

Valve closed

Description is included below.

Draining process

1) Drain valve #1 is opened and mixture is drained into molding machine

2) Strain gauge periodically checks if mixture has decreased to 'empty' level

2b) By the 'x' check and strain gauge records 'little' to no decrease in weight then, alarm is sound, process is stopped and problem logged.If problem can be fixed process will be resumed, if not process will be reset and shutdown.

3) Signal is then sent to molding machine

4) Drain valve #1 is then closed and then "cleaning cycle" is started

The cleaning cycle is shown below. It would also be programmed in CFC with complex parts called up in structured text or instruction list.

Cleaning cycle

Cleaning cycle

Mixer lowered

Water added

Mixer started

Clean process

Manual/Auto start process

Description is included below.

Cleaning cycle

1) Mixer lowered and motor started according to 'cleaning setup'

2) Water valve is opened and 200kg of water is measured by strain gauge then water valve is closed

2b) If strain gauge measures increase in weight above the required amount and keeps increasing, problem LED is lit and alarm is sound. Problem is logged and process is STOPPED and reset

2c) If strain gauge measures increase in weight above the required amount and stops increasing, drain valve #2 is opened until the correct weight is obtained.

Task Mapping I/O Type Address DescriptionStrain Gauge strain Analogue_In %IW2001 (0-10V) Loop Suplied Pressure SensorHall-Effect Sensor motor_s Digital_In %IX4000.0 Fast Counter Pulse Speed SensorUp Limit Switch up_ram Digital_In %IX4000.1 Mixer Lift Ram Home Position Mid Limit Switch mid_ram Digital_In %IX4000.2 Mixer Lift Ram Cleaning Level Height SensorLow Limit Switch low_ram Digital_In %IX4000.3 Mixer Lift Ram Mixing Process Position Motor Fault m_fault Digital_In %IX4000.4 Temperature/FailureSafety Guards safety_g Digital_In %IX4000.5 4-Switches, input is common E-Stop Switch e_stop Digital_In %IX1.0 Emergency Stop Switch (Process Stop)On/Off Toggle Switch on/off Digital_In %IX1.1 Main SwitchMotor PWM pwm Digital_Out %QX0.0 Motor Speed Control Cocoa Slide Ram slide_ram Digital_Out %QX0.1 N/C Spring ReturnMixer Lift Ram mixer_ram Digital_Out %QX0.2 N/up Hydraulic ReturnPalm oil Valve palm_v Digital_Out %QX0.3 N/C Spring ReturnEmulsifier Valve emul_v Digital_Out %QX0.4 N/C Spring ReturnWater Valve water_v Digital_Out %QX0.5 N/C Spring ReturnDrain Valve #1 valve_1 Digital_Out %QX0.6 N/C Spring ReturnDrain Valve #2 valve_2 Digital_Out %QX0.7 N/C Spring ReturnSiren Alarm/GSM Alarm alarm Digital_Out %QX1.6 Emergency Warning System Maintenance LED maint_led Digital_Out %QX1.1 Periodic Maintenance IndicatorFault LED fault_led Digital_Out %QX1.0 Process Fault IndicatorMotor F/R m_f/r Global_VAR nil Motor Direction Control Cocoa Level Sensor cocoa_s Global_VAR nil (4-20mA) Loop Supplied Pressure SensorPalm oil Level Sensor palm_S Global_VAR nil UltraSonic SensorEmulsifier Level Sensor emul_s Global_VAR nil UltraSonic Sensor

2d) If strain gauge measures decreasing weight or no weight gain during filling then problem LED is lit and alarm is sound, and problem is logged and process STOPED and reset

2e) If strain gauge measures underweight after valve is closed then it will slowly increase weight by opening the valve until weight is achieved

3) Timer 4 is started (5 min)

4) Once timer 4 is done drain valve #2 is opened and water is drained

5) Strain gauge will periodically measure the weight of the remaining water and if 'little' or no decrease in weight is achieved within 'y' cycles then alarm is sound process is stopped problem is logged. If problem can be resolved then process will be resumed if not process is STOPPED and reset.

6) Valve #2 is then closed and Cycle decrements it job list by 1 cycle and returns to "home screen" (cause of cycle count returns to cycle point)

I/O List