Inspecting output conditions

Hello everyone !

Having multiple conditions for one output , how can I monitor which one of them triggers the output? I am referring to inputs that might be triggered randomly and very fast.

One way would be to have counters for these inputs and look up for them ,but this would mean that I have to reprogram the PLC and upload the new program.

I would like to know if there is a tool for this kind of inspection that I can program on the fly . I am using Schneider Unity Pro XL 10.


Let me know if you need more info on my problem.



Thank you in advance !

Memory latches.
I also had a colleague of mine that created a function to log certain number of boolean's inside the PLC as in his case it was more than one condition that happened and he needed to understand which happened first.

Can you please give me a simple example? Also this has to be programmed on the fly without rebuilding the program if possible. If not I still want to see your suggestions!
Thank you

Maybe try a FIFO block

Full description is in the help file...

Have each condition set a different bit in the load word of a FIFO and load
then if that first word of the FIFO is not equal to 0 set the output if 0 clear the output
don't forget you have to unload the FIFO when it get full or it will stop excepting new data.

Thank you for your replies!

Let me check FIFO blocks and I will be back to you