Help: PLC Logic for specific condition using one shot rising

[dpionk]

RSLogix 500 v9
OSR storage bit & output bit

I am programming a sonic welding generator and I am stuck on an operation I need to perform and I'm kind of stuck on the best way to keep track of what I need to do.

The process I need to keep track of number of welds performed. The only signal I have from the generator is a ready signal. When I send the process on signal my ready signal goes low then high then I need to drop out my process on signal 20ms after that. I have that part down but I can't figure out how to count my welds I was thinking a OSR bit but cant figure out how to use it with the storage bit and output bit.

Sequence of events:
Ready signal is 1.
I output my process on signal to 1.
ready signal changes to 0
sonic welds.
ready signal changes to 1
25ms delay I turn off process on signal.

 

[cwal61]

I think I would parallel the counter below the timer and use the timer done bit to count. Timer Done is Weld complete. So that's when you count. When count equals correct value and process is complete then Reset. No need for one shot if you use CTU Instruction, It transitions once on false to true and will only give a 1 count per transition. If you use an ADD Instruction that would require a one shot because it will add while true on each scan cycle.

 

[kolyur]

Unless I'm missing something, you should be able to just trigger a counter instruction (CTU) with one of your process control bits such as B10:0/1. The RSLogix counter instructions only increment on a false-to-true transition of the input logic... think of it like a built-in one-shot.

 

[dpionk]

I think that I was overthinking this thanks guys! I will do that