High speed counter

I’m using high-speed counter to control the position of the belt. In order to determine that the belt stopped I would like to compare to consecutive numbers. So far I have not been able to achieve it. I can use the timer to control the signal activating the counter, but I would feel much comfortable with comparing the two consecutive numbers. Can any one have any tips for me?

Thank,

The mechanics depend on the PLC model, but most PLCs will let you copy the accumulated value from timers and counters to a separate data register. You can then do any comparison or manipulation required.

Thanks Tom,
My problem is to compare the stored number in memory and the current number from counter. The signal from encoder (I’m using proximity switch and daisy wheel) is the driven factor. I’m not able to use that signal to move and in next shot compare the numbers.

Use the prox input N.O. to drive one timer, the same prox input N.C. to drive another timer. Use the timer done bit N.O. from both timers in parallel (OR) to drive an output. If either timer times out due to lack of change, you will get an output to indicate the stopped condition. Use that in the rest of the logic for control.

It would help if you tell us what brand and model high speed counter. As Tom mentioned, different models offer different features. Many have a 'counts per timebase' feature which might give you what you need.

Otherwise try something like this:

Start of ladder logic

If current HSC data = stored value then set 'Stopped' flag
Else reset 'Stopped' flag

Move current HSC data to storage register.
...
Balance of ladder logic
...
End of ladder logic

Hi Steve,
I'm using OMRON-CPM1-40I/O

Rate meter

Why not use a rate meter with adjustable low speed setpoint?
It does not seem like a counter app.