Micro850 High Speed Counter Problem: Cant read over 69 hz

I have a square wave being put into the Micro850 input channel 0. I have tried with counting the rising edges with code and with trying the high speed counter example in the user manual. Both act the same. When I do 69 pulses a sec or 69 hz the counter doesn't miss any. When I go to 70 hz the pulse counter starts missing by about 10 pulses.

My system speed sysva_TCYCURRENT is 0 to 1 ms
SYSVA_TCYMAXIMUM is 3 ms

When I try to use the high speed counter I do get the data back out of hsc.accumlator so it seems like its working.

If I go over 100 hertz it doesnt even register 1 pulse or count?? Which is weird the specs says all 24 DC model Micro 800 have 100 Khz high speed counters. We arent even close to that? Is this the upper end limit of the 2080-LC50-48QWB Micro 850 plc or are we not using the code right?

I set the Embedded I/O input filter to 5 microSeconds and the EII edge to rising and Im at 200 counts on 200 pulses!!!

Cant access the pdf on rockwells site. Can anyone send me information about the embedded IO EII edge and filtering documentation?

This is almost certainly a discrete hardware input filter issue.

The default input filter on most A-B DC inputs (including the Micro 830/850) is 8 milliseconds, intended to filter out noise from 60 Hz sources, and consistent with what you're seeing.

I'm not experienced enough with the Micro 800 to know how the filters are applied for general-purpose inputs vs. the hardware high speed counters.

500 pulses on 500 hz!!!! Will test more tomorrow

Ken Roach said:

This is almost certainly a discrete hardware input filter issue.

The default input filter on most A-B DC inputs (including the Micro 830/850) is 8 milliseconds, intended to filter out noise from 60 Hz sources, and consistent with what you're seeing.

I'm not experienced enough with the Micro 800 to know how the filters are applied for general-purpose inputs vs. the hardware high speed counters.

Click to expand...

This would be my bet too. The image I've attached is from v10 CCW, but it should be similar to whichever version you are using.