Centroid Community CNC Support Forum

Good to have some clear instructions for reduced resolution.

On machines with higher motor revs/inch, it is helpful to be able to spin the motors faster. At 32768 counts/rev, you are limited to 2268 RPM at the motor due to Oak bandwidth limitations. I have done several Yaskawa installation where I used 4096 lines / 16384 counts per revolution in order to get the motors up to their full speed.

cncsnw wrote: ↑Sun Jan 12, 2020 8:32 pm Good to have some clear instructions for reduced resolution.

On machines with higher motor revs/inch, it is helpful to be able to spin the motors faster. At 32768 counts/rev, you are limited to 2268 RPM at the motor due to Oak bandwidth limitations. I have done several Yaskawa installation where I used 4096 lines / 16384 counts per revolution in order to get the motors up to their full speed.

Thanks Mark, as always your experience and knowlege is always appreciated!
I think for most "typical" knee mill, bed mill, lathes your recommendation of 4096/16834 is more than reasonable. I think even 2000/8000 is reasonable.

Marty

Marty can you please post pic of your pid on those dmm just trying to see if i can get it close. im using velocity mode. but might need to hook it up in precision mode to get them close atleast. any help would be great.

Not velocity mode! Precision mode for Oak and DYN4. Did you not get the DMM document?

I have to use it in velocity mode. Cause im reusing my glentek drives for the other axises

occustoms wrote: ↑Sat Jan 18, 2020 1:09 am I have to use it in velocity mode. Cause im reusing my glentek drives for the other axises

Never been tested that way. You might have better luck just buying new drives and motors and making them all the same. Not saying you can't. Talk to DMM about it.

I have they say shouldnt be an issue. But im having a hard time doing the pid system in centroid control. so i was hoping that i could use yours for a base line and try that. other option is wire it up pos mode, and do the auto pid and try that. they also have a parameter i seen that sounds like it mimics the velocity mode but says it will have mismatch errors.

So could you post up the pid for me to try before i go through all this plz? I understand it might not work.

but i dont want to spend 4500 on centroid drives to do my other axises.(that is my really last resort) since im already this deep into it. im hoping doing the glenteck drives wont be this hard. but that is next to conqour.

If you don't have any other guidance for velocity mode PID tuning, try starting with Kp = 0.01, Ki = 0, Kd = 0.

Then you can increase Kp until you get signs of instability, and back off.

Then optionally add some Kd (maybe starting equal to Kp and working up from there).

Ill give it shot. but ive tried about everything. lol. other thing is that im using this for a forth axis and my rev per in is 1/360 so its like. .0027777778
and everything in the manual and everything else i seen is 5.0 and up. Manual says that the rev/in makes a huge difference on pid system. And i have changed it to 5 and it does act totally diff.

Hoping maybe a one of the centroid tech people can help. But it is redicoulsy hard to get them on the phone and keep them on the phone when you do get someone. Maybe if i pay for the tech support hrly itll make a differnce.

Also it this will be geared later on when it is on a harmonic drive 80-1 reduction. i hope this doesnt matter. but im having a feeling it will. also just outputing the the 8000 resolution encoder not the 32768.