More information can be obtained at our website. http://accautomation.ca/plc-programming-example-shift-register-conveyor-reject/ We will apply the five steps to PLC Program development to our next programming example of a shift register - conveyor reject. 1.Define the task 2.Define the inputs and outputs 3.Develop a logical sequence of operation 4.Develop the PLC program 5.Test the program Another example of programming PLC Shift Registers can be seen at on our product sorting application. This will use 3D factory IO to demonstrate sorting colour tags. PLC Programming Example – Sorting Station (Shift Register) http://accautomation.ca/plc-programming-example-sorting-station-shift-register PLC Programming Example - Sorting Station Testing - Video https://youtu.be/W0aibYb3DnE PLC Programming Example - Sorting Station - Video https://youtu.be/YMl2DPm_yaU http://www.accautomation.ca

1. Five Steps to PLC Program
Development
Conveyor
Reject
(Shift Register)

2. 1. Define the task:
 What has to happen?

3. 1. Define the task:
A start pushbutton (NO) is used to start the conveyor and a
stop pushbutton (NC) is used to stop.
Sensor B detects product on the conveyor belt and sensor
A will detect if it is too large and needs to be rejected.
The product is tracked along the conveyor belt and when
under the reject station the Reject Blow Off will expel the
bad product. Product is randomly placed on the conveyor
belt, so an incremental encoder is used to track the
conveyor movement. The reset pushbutton (NO) will signal
that all of the product on the conveyor has been removed
between the sensors and reject blow off.

4. 2. Define the Inputs and
Outputs: Inputs:
Start Switch – On/Off (Normally Open) - NO
Stop Switch – On/Off (Normally Closed) - NC
Reset Switch – On/Off - NO
Motor Encoder – On/Off – This will give a discrete signal
when the conveyor is moving. It picks up the movement
of the free wheel.
Sensor A (Part Reject) – On/Off - NO
Sensor B (Part Present) – On/Off - NO
Outputs:
Motor – On/Off (Conveyor Run)
Air Blow Off – On/Off (Reject)

5. 3. Develop a logical sequence of
operation:
Use a flow chart or sequence table.
Fully understanding the logic before starting to program
can save you time and frustration.

6. 3. Develop a logical sequence of
operation:

7. 3. Develop a logical sequence of
operation:
Review this sequence with the person with the
most knowledge of the machine. This can be the
designer and / or the machine operator.

8. 4. Develop the PLC program:

9. 4. Develop the PLC program:

10. 4. Develop the PLC program:

11. 4. Develop the PLC program:
Document, Document, Document!
This save you time and money when you have to
return to the program years later.

12. 5. Test the program:

13. 5. Test the program:
Test the program with a simulator or actual
machine. Make modifications as necessary.
Check with the people most knowledgeable on
the machine, to see if it is doing what they
expect.

14. 5. Test the program:
Follow up after a time frame to see if any
problems arise that need to be addressed in the
PLC program.

15. PLC Program Development
The five steps form the basis of all PLC
development. You will notice that the actual
programming does not occur until the second
last step. Usually more time is spent on clearly
understanding the task and sequence of
operation.

16. ACC Automation
Practical Tips and Techniques
Conveyor Reject Application – More information
can be found on our website
Conveyor Reject Video
More PLC Programming Examples