Mesa 7i96s a little jitter

Ok thanks pcw I will do that. When I compare your scope plot (attached) from here forum.linuxcnc.org/38-general-linuxcnc-q...7i76e-solved?start=0
to mine (also attached) mine seems to have magnitude 10 worse joint follow error (after conversion to mm) and at least double the dpll phase error plus the spikes. Your joint follow error also appears to be zero at constant velocity where as mine is not. I’m trying to get it similar to yours as that’s what it should look like correct?

Yes, it looks like you are not using the DPLL.

Can you post your hal/ini files?

Yes but I don’t have them right now. I do know that there is no mention of dpll in either hal or ini as I searched for it. I used pncconfig (which had the 7i96d option) and the 7i96s out of the box.

Yes, it looks like the pncconf 7I96S configuration is missing the DPLL setup.

Adding:

setp hm2_7i96s.0.dpll.01.timer-us -100
setp hm2_7i96s.0.stepgen.timer-number 1

to your hal file should fix it.

Great thanks PCW, I wish I’d tried this at the beginning but I went off down the intel Ethernet route just assuming it must be a difference with the 7i96s - anyway will try it out and report back.

Disabling IRQ coalescing should always be done with Intel MACs
as it lessens the likelyhood of a real time error