2080-MOT_HSC - extracting the Z pulse

Hi,

I'm using the 2080-MOT-HSC High Speed Counter plug-in module with a Micro850 (2080-LC50-24QWB) using the HSCE instruction. The encoder is a 2500ppr model with ABZ & complements.

At the moment, I'm having to resort to using the Z pulse that is assigned to the 2080-MOT-HSC's IO - _IO_P1_DI02 (with the HSC in plug-in slot 1). This input bit comes on and off with the Z pulse. This all works fine unless the encoder is going too fast or is geared-up, presumably because I'm reading it in the general program scan and the Z pulse is going on and off too fast to register. The count is captured accurately at higher speeds because it's via the HSCE instruction.

I *think* my solution may lie with the TPValue output of the HSCE function but I'm struggling to find any information on it. I know that TP stands for Touch Probe and I'm assuming that Touch Probe is a synonym for marker pulse. That may be a dangerous assumption, aren't they always?

Can anyone give me insight on how to capture my marker pulse asynchronously, please?

I opened a case with Rockwell TechConnect. The initial agent was able to point me to a Z Input function setting which was on CCW's Micro800 configuration tab, in the tree under 2080-MOT-HSC/Counter0. It was unassigned. I changed it to Preset. This should load the counter accumulator with the counter's preset value that is set by the HPSetting input of the HSCE_CFG function block. However, it didn't appear to work for me. The case has been escalated to a 2080-MOT-HSC specialist and I'm waiting to hear more. Hopefully, I'll remember to update here, if and when I do.

This is the reply I received from the Rockwell support guy:

"I got a response from the commercial engineer:

The Z pulse is not affected by the PLC scan time. If you need the Z pulse to be triggered at higher frequency, you need to adjust the input filter.

I remember you set the input filter to 2μs. To check if it works correctly you can set up a sample program:

<see attched screen shot>


I set Bool1 for resetting the counter. The CV should increase even if the pulses are coming in faster than the PLC scan.

If this is not the answer you are looking for, please describe what should be the purpose of the Z input in your program."

I find it hard to believe that this is correct and it's not borne out by what I'm seeing and that's with the filter time set at its fastest setting. My only other option would be to have no filter, which is fine, but I'm not sure how much improvement it will make over a 2 microsecond filter.

I haven't tested it yet but I can't see how it can work if, for example, the Z pulses were coming twice as fast as the PLC scan time.

Any thoughts?