Omron CJ2M - making RPM from a binary input

Hi!

Need some help on a schoolproject!

We have an optical sensor, that counts 12 pulses per rotation on the shaft on a machine.

I would like to convert this information to RPM, it is some kind of function in the PLC i can use, or must I make it myself?

I have tried making a FB but I cant get it to work, it is attached.

Thanks for any help!

If you want that PRM value is updated every minute:

Use a timer 1_minute to generate one-shot pulse everuy minute (CLK pulse)

Use a DM0000 and increment it continuosly od each postitive change of IN pulse from sensor.

When CLK pulse is on, then:
-Divide DM0000 with 12
-Stroe reult in DM0002 (that is RMP)
-clear DM0000

Each minute you will get a new DPM data in DM0002.

If you want that PRM value is updated continously:

Measure time interval between two IN pulses (from sensor), using internal 0,02sec pulse. (50 pulses counted = 1 sec =1/(60*12) rpm

Reset measurement on falling edge of IN pulse.

If you want to use intergated HSC (high speed counter) inputs (if exists on CPU):

Use instructions foh HSC.

CJ2 does NOT have High Speed Counters on base PLC! You would need to add either a CJ1W-CT021 HSC module OR a CJ2M-MD21 Pulse I/O module to use HSC functions.