@Forum-user Looks like a MKS SERVO42C V1 board. See https://github.com/makerbase-mks/MKS-SERVO42C/wiki/MKS-SERVO42C-V1.0-Home

I'll have a look tomorrow how it can be wired. I'd guess you need to use the on-board interface to set the mode, covered here https://github.com/makerbase-mks/MKS-SERVO42C/wiki/Menu-instruction-V1.0

Ian

@dc42 Thanks for the info!

The quadrature linear axis encoder configuration sounds like what I need! The only issue it that I'm limited on the number of wires I can string back to the control board and the 10 pin SPI header is quite a bit of cable, also the path back to the control board is further than the recommended 200mm 😞

Also, I just realized that this setup is basically a servo, just replacing a potentiometer with an encoder. Is there a mode in RRF that allows you to drive a stepper motor in open loop mode targeting a potentiometer / encoder value? Essentially turning a stepper motor into a servo?

Thanks again for the help!

@dc42 thanks for your reply. I will try bump it up a bit. It does sometime become unstable however if I increase D. Will play around more. How many oscillations should you be aiming for about setpoint? I have done a bit with PID in pump stations and heating, but nothing with response like this/required accuracy.

Ok cool. Thanks for explaining. I might talk to Jason and see if he can send me the motors without encoders and will swap them over as he said at some stage he would get 1.8 degree motors sorted.

Cheers
Sam

@Shoki
Have you done a PID tuning for the hotend with the fan running full blast? In another thread, I read it was running at only 70% during PID tune...

Managed to figure it out. In all of my playing around I forgot to change the C parameter back. Now to deal with the tuning as it is sitting there humming

Sam

@gost101 That will be fine as long as you don't draw too much current for the 5 Volt supply or the connector you are using.

@elixirtrip well some info is already here. For now there is a board that can go to can bus without a driver and you can attach your own external closed loop (leadshine, odrive ..):

https://forum.duet3d.com/topic/16257/ac-servo-motor-driver-control-by-duet-3-mb6hc-help/5

https://forum.duet3d.com/topic/17148/duet-3-expansion-1xd-can-fd-single-external-driver-controller?_=1592917797395

https://forum.duet3d.com/topic/15975/duet-3-nema-23-closed-loop-with-z-axis-also-using-elec-brake/16

@dc42 that would be awsome, I am guessing that the encoder will be used primarily for position/movement verification.
I have a stepper driver that supports the use of an encoder for position verification and commutating the stepper motor as high pole count bldc to run a control loop on the curent of being applied to maintain rotor position. It can help quite the stepper down versus the standard noisier position verification mode but I don't think there is much to be gained over the existing silent nature of the trinamic drivers using that approach. One advantage it does provide is the ability to momentarily over drive the motor to overcome a high torque demand that would normally cause a stepped to miss a step.

All in all really exciting news