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FIFO / LIFO use in RSLogix 5/500/5000

S

Thread Starter

Scott

Hi, we have an application where we are using a FIFO list to track parts moving through a queue. The FIFO Load/Unload pair is working without issue. We now have the situation where we would like to add another object back into the top of the queue on an irregular (triggered) basis and have it be used by the next FIFO instruction. What would be the best way to make this happen? is it possible to use the LIFO load command with the FIFO control var and have it achieve the desired result?

We have AB PLC-5/20E (RSL5) & ControlLogix 5555 (RSL5000) units.

Cheers,
Scott
 
J

Jeremy Pollard

Check out the operation of the FIFO - the data in the file is moved up and down in the stack... you can separate the stack and place your new data into the file. Then add 1 to the index 'pos' and the data is then in the stack at whatever position you need.

Cheers from: Jeremy Pollard, CET The Caring Canuckian!
www[.]tsuonline.com http://www.tsuonline.com/
 
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