Encoder issue with IDC5Q

Hi, I’m using a 5000 PPR X4 type encoder with an IDC5Q module and Snap-Pac-R1 controller. The problem is that I could only read negative counts in both directions when monitoring from Pac manager Digital bank. One direction counts fast and the other counts slower but both accumulating negative counts.

The same program has been successfully used on more than 30 machines but with 500 PPR encoders. This time is a 5000 PPR X4 encoder, but the IDC5Q is able to pickup up to 25K, so it shouldn’t be a problem. Did I miss anything here? Any comments will be appreciated.


Have you had a good solid read of our quad counter tech note?

The fact that it counts down in both directions is a big red flag to me. Something is not right as one clock should lead the other in either direction. The fact that one always leads and always results in the down count? Yeah, something is not right… Either with the encoder or the wiring is where I would start.

Also the blanket statement of 25k should be qualified. It depends on your encoder PPR and RPM.
You have done the math in the table on page 3-4?

Thanks for the information. Sorry I forgot to come back to update. The problem was caused by a faulty rack, it was solved by replacing the rack.