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Parameter 78 - Solved
Posted: Wed Jan 24, 2024 5:34 pm
by chronolite
Can someone explain P 78 in practical terms for me? This happens on several lathes for me, so I'm curious as to the behavior why. Here are some conditions:
Set P78 to 1
Goto MDI
CYCLE START
Spindle goes to 30 rpm.
Set P78 to 7
Goto MDI
CYCLE START
Spindle goes to 55+ rpm, I freak out and stop the spindle.
This happens on two different machines running Oak.
I know that 30 rpm or 55 rpm doesn't seem like much, but on a 88" chuck, that's scary fast.
Re: Parameter 78
Posted: Thu Jan 25, 2024 1:07 am
by cncsnw
That certainly does not sound right.
What CNC12 software version(s) are you running?
Do you get correct spindle speed response with P78 = 0?
Does the error (running too fast) happen with P78 = 3? What about with P78 = 5? Perhaps we can narrow down which specific feature is adversely affecting the spindle speed commands.
Re: Parameter 78
Posted: Tue Feb 20, 2024 10:14 am
by chronolite
I set P78 to 0,1,5, etc, but that didn't help much.
I think the issue was that the min/max spindle speed is what determines the 0-10v scale, (in Setup - Motor). I was hoping it was smarter than that. If there's a parameter we can adjust to slave the 0-10v to the encoder pulses, that would be a lot cooler. I also have a problem with the wording on the min/max, since it's relative to high gear. (This particular 100hp machine is certainly capable of spinning its 88" chuck at 500 rpm, but no way would I want to be near it).
So here's a tip for those in the future looking for why this occurs: If your spindle drive has a max RPM setting at 10v, that's exactly what you need to have in the motor setup. It appears that spindle encoders are only used when they are in a slaved operation (like threading).
Rookie mistake, thanks for your help guys.
Re: Parameter 78 - Solved
Posted: Tue Feb 20, 2024 12:22 pm
by tblough
Spindle encoders are only used to read spindle rpm. Centroid does not use them to control rpm.
Re: Parameter 78 - Solved
Posted: Fri Feb 23, 2024 5:00 pm
by cnckeith
post some photos of this machine , sound interesting