SouthWestern Industries Prototrak servo drive replacement with A-M-C 12A8

OT-CNC, Many thanks for the help. The J1 replacement was only successful for 1 of the 25a8s, so I ordered and soon I will receive a set of BE25A20s with the hope this will workout ok. I have attached a diagram (that I left out the GND (on CP3 location 5 on BE25A20) to TB3 (7i77 card) location 3 GND) that I plan to use, wondering about a 2nd opinion? I have attached a .pdf of the BE25A20 data sheet. I plan to adjust POT 1 full CCW; adjust POT 2 to mid point (7 turns CW from full 14 turns CCW) to allow max od 12 amp, I believe is what the motor is rated at. Could use 2 opinion here as well, the delivery is suppose to be Thursday by 9:00pm. Any help warmly welcomed.

Many thanks to ALL, that bring the things together to make this forum happen.

This link might help you:
forum.linuxcnc.org/27-driver-boards/2876...-torque-vs-tach-mode
forum.linuxcnc.org/39-pncconf/19939-mesa...figuration?start=144

I would connect the ground from the encoder to the ground on the feedback connector.
Midpoint on pot 2 should be fine for 12.5a. or turn it more ccw to be on the safe side. There is an an-011 doc that goes into detail on that or double check with AMC.
I'll see if I can dig it up. There are also some switch settings if you're connecting the brush motor to brushless drive explained in an-007 doc.

If you're connecting the encoder to both the drive and linuxcnc you would be running it in encoder velocity mode, correct?
Look over the mode selection table and set your dip switches for encoder velocity. (if runaway, reverse sw7)
If that's the case, pot 1 would not be at full ccw as that suggests current mode. I think mid point would be a good start. I can dig up my notes to see what worked for me.
Here is what I found:
pot1- start full ccw then increase gain until motor squeals, back off 1 turn or what ever number works for you.
pot3- my notes show full CW as that represents full 10v reference signal
pot4- adjust drift, start in the middle and adjust until motor no longer moves at rest. (it my drift slightly in open loop, just get it close)
Make all the initial above adjustments without linuxcnc interfering. Again, have an estop/disable working while testing. 50/50 chance of a runaway.

Benb, and OT-CNC Many thanks! I read part of the links that Benb refers to and will finish soon. The update on delivery, the drives will be here Monday, end of day.

OT-CNC, I have seen the SW1 settings table referenced to in the attached data sheet. I will be following your suggestions and set up drives after I receive them. If you have better/more complete data sheet please post.

Many, many thanks for the all the help and support.

If you have better/more complete data sheet please post.

No, same drive doc and only what I have attached on previous post. (an-011 and an-007)

OT-CNC, Many thanks! Until next week (when the package arrives) I will read and ponder the data sheets and your suggestions. I am wondering if I should start fresh/new post with a subject line describing the project, so others that may search to read in the future will get to the how to, vs. the micky mouse history of the project.

I want to send out a special thanks, to the following for the continued help and support: OT-CNC, Todd Zuercher, Benb and the moderator piasdom, Many Thanks!!

I have started a new post at this link:https://forum.linuxcnc.org/12-milling/41057-prototrak-plus-southwestern-ind-using-a-m-c-be25a20-driver