stepgen dir signal

hi, I have a closed loop system with 4 pwmgen plus a stepgen for axis a.
mesa 5i23. looking at the oscilloscope I saw that the pin direction of the stepgen is sometimes a square wave with 50% duty cycle. Is this normal?
however it works everything was just a curiosity.
thank you
Mauro

The stepgen is basically a servo system so can dither somewhat. if you use the PID setpup you can usually
rid of this behaviour with proper tuning

I do not have the pid for axis A. better to put it?
I found a mini itx industrial iei kino dh610 with i5 4 GB memory I'm going to 8khz with the 5i23 and the servos DC work perfectly.
when I have finished I can post all the details because it seems to be a 'great card
fast and very little latency even with rt-preempt.

The PID based stepgen control works somewhat better then the built in position mode control in the driver, though I doubt you would notice any real difference

at least now the signal seen at the oscilloscope is perfect and dir no longer oscillates.
how did P = 125 being an 8khz okay? I'm a donkey doing the calculations
Thank you
Mauro

You can use up to P=8000 at a 8 KHz servo thread
( P= servo thread rate means correct any position error by the next thread time)

Anything higher will result in overcorrection

You may not want to go as high as 8000 without DPLL firmware, as servo thread jitter
will cause random bogus velocity corrections and the magnitude of these corrections is proportional to P