Spindle PID question

[spumco]

Just updated from 1.2029 to 1.2037 and Ger's appropriate screenset as I wanted to take advantage of the updated pulley calculation features you implemented in the past couple of beta versions.

Previously, I had to use a spindle speed workaround since my spindle encoder was behind the pulleys (52/36 ratio) - so I turned off the pulleys and 'tricked' UCCNC by telling it my 400ppr encoder was a 277ppr. Worked like a champ and with a separate spindle index trigger I could rigid tap.

I've now set the pulley ratio and encoder to their real values and everything works well with the PID off - thanks for the fix.

The problem comes when I enable the PID loop on the spindle. No matter what settings for P, D, or I are entered the controller spins the spindle at 1.444 times the commanded speed.

Enable the PID - 1000rpm command causes 1440rpm in Sact. Disable the PID and it controls within 1 or 2 RPM.

The PID loop settings are working - I can fiddle with the P/D/I values and the spindle 'hunts' or calms down and generally acts like a PID loop. It's just off on the output speed by the pulley ratio.

So... is the PID loop ignoring the pulley ratio calculation? If the PID calculation & adjustment is happening after the pulley ratio adjustment, then the PID might override the intended spindle speed. This appears to be what's happening, but I'm not knowledgeable enough about programming and 'order of operations' to be sure.

And yes, I've done the "apply settings" and "save settings" after every change. Learned that one a while ago...

This isn't a crisis as the spindle is working well enough to do peck tapping and I don't generally load the spindle so high that it bogs down, but it'd be nice to try this feature and see if it improves surface finish or other variables.

Thanks,
Spumco

[cncdrive]

Hi Spumco,

Thanks for the report.
My collegue will check this issue out soon and I'll update you with news asap.

[spumco]

Thanks for looking in to it. I'd really like to try the PID out.

[spumco]

Any word on the PID vs. pulley ratio apparent conflict?

Thanks,
Spumco

[cncdrive]

I've asked my collegue a few days ago and he said he changed the code to make it work how you described that it should work, but he said he could not test it yet.
So, I will have to ask him if he could test it and will let you know asap.