[PLC Sample Code] - Conveyor FIFO (first in first out) w/Reject

[Chris Elston]

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Conveyor FIFO (first in first out) w/Reject

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Classic example of a FIFO (First in First Out) Load and Unload.

Application was bottles coming down a conveyor system at a "variable" rate and sporadic. Sometime 10 bottles would be grouped together all in single file others they would be spaced out oneisy twoisy.

A photoeye was used in a vision cell up stream this photo triggered the vision system and loaded the FIFO at the same time.

A photoeye was placed downstream next to an air blow off nozzle. This created a "zone" at which you could load and unload the FIFO and keep track of bad bottle in-between your zone. Bottle QTY could vary between the vision photoeye and reject photoeye.

The vision system was triggered and part status was loaded into N7:0. A 1 means good part a 2 means bad part. The 1 or a 2 was loaded into a FIFO and placed into N7:1 at the reject air station. If the FIFO status equals 1 at reject it was allowed to pass if equal to 2 the air nozzle was turned on under a timed blow off.

This was a field installed retrofit project that involved a 10 point Micrologix 1000 that cost $72.00 4 Keyence Vision systems and 2 Banner EZ-Beam photoeyes. Cake work.

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• Submitter
  Chris Elston
• Submitted
  07/12/2006
• Category
  PLC Sample Code