MicroLogix 1400 HSC

[roxusa]

Is it possible to set up the HSC in the 1766-L32BXB as a ring counter.
So it will roll over to 0 counting up and continue to count up that direction,
and roll back to that number when counting down and 0 is reached.
This would simplify my programming. Thanks

 

[roxusa]

It looks like I need to use the OVF & UNF in conjunction with some of the other settings
to accomplish this, I am not That familiar with the HSC I have only set them up a few times
for standard encoder up/down counting

 

[BlueAltezza]

I don't think you can change the counting direction on the fly - those bits are read only and would be set in the function file directly.

A few ideas:
Split the encoder signal to another input and set up two high speed counters. In your case you could set the 2nd counter to always count down. You'll have to set your logic to enable/disable the counters based on events, presets reached, etc.

If you can't do two counters you might have to add some other logic that interprets the high speed accumulator differently based on your count direction. Use the logic to create some high or low targets and then compare the high speed counter's accumulated value against those targets.

If you need it a bit faster than the normal scan time, set a 1ms STI to do the comparisons.