detection pulse with a couple of rungs

Hello,

I use a PLC/5 and RSLogix5 software.
How Can I detect a input pulse (I:00/00) with some program-code?
The pulse that I must detect is a false to true and
then from true to false type.

mulderm

Here is a snip from a PLC5 program where it is required that the operator remove the part at the end of a cycle and insert a new part. It requires that a dark operate photo eye first turn OFF, then back ON. Inverting the logic may give you what you want.

You could also use an OSF instruction.

Thank you for the information Alaric.
I have also another option.
See attached file.

mulderm

Mulderm, I also saw your post on the other borad....

The instructions you used in your solution (in line OSR) are SLC500 instructions - where as on the PLC 5 OSR is an output instruction.

In the PLC5 I would do that function like this with an OSF.

XIC I:0001/00 OSF B3:0/2 1 B3:0
XIC B3:0/1 OTL B3:0/0

Here is how I implemented a falling edge one shot in a ML1000 on a vacuum furnace. In this case, I could not use XIO B3/17 OSR ??? in this application because it would produce a single shot output on the first scan as well, which was not acceptable in this application. B3/17 had to first actually be on, then off. When that condition is met, B3/25 will be on for a single scan. This takes advantage of scan order to accomplish the falling edge single shot.

Very clever, Alaric.

You are great Alaric.
This example is exactly what I mean, much better als
using a counter what I have used.
Many thanks,

mulderm