Servo Tuning, mystery servos. Videos too?

[Thinkin]

I am starting to test my refit project. A 1982 Lagunmatic 310 CNC mill, centroid all in one. The issue is that I can't identify which servo motor option this machine has. The options were a 9A or 13A 70v dc servo motor. They are big beefy units and if I had to take a guess it would be the larger of the two. I do have the original motor drives in a box and they were rated for 10A continuous and 22A peak. But who knows. They are 5" in diameter and 13" long including the encoder covers.

Any guesses on what sort of numbers I should use for Kp, Ki, Ka, Accel etc? I also have no idea on RPM limits for these motors but I don't think that is an issue here.

Also does anyone have a link to a good video on PID tuning these motors, or for what to do at this stage of the build? I have not connected the motors yet but I think I am near that point. Belts and wires are still off. I had to drop this project for several months so I am fuzzy on what I read way back then.

I am also looking for a good tutorial for adding manual buttons to the visual control panel as I need to start assigning PLC functions to the Virtual control panel. I won't even think about tackling getting my Geneva drive tool changer working under cnc 12 until I do a lot more reading on how to code it but I need to assign the functions to the buttons on the screen for now so I can manually run the spindle tool lock etc.

[martyscncgarage]

Post pictures of the labels on your motors
Go here, find the VCP 2.0 User's Manual.
Also watch the video:

[Thinkin]

If the motors had labels, I wouldn’t be in this predicament. The best I found is a mention of a couple of part numbers here. My google fu has returned no results.

[Thinkin]

Mystery Lagun Matic servo.

[martyscncgarage]

Understand.
I can't help but wonder if it wouldn't be better to replace/upgrade those old nearly 40 year old DC Servos. If you spend the money on All in One DC, and one of your motors dies, you are stuck with having to replace it with another DC brush Servo motor. Not a terrible deal.

Is this for home hobby use?
I assume the machine has no handwheels?
You might consider Acorn and some new AC Servos?

Marty

[cncsnw]

"M-4070" and "M-4090" sound like Baldor part numbers. Not that it matters much. You won't find a table that says "these are the exact optimal PID gains for a Centroid CNC11/CNC12 control" indexed by every SEM, Baldor, or Glentek motor model ever sold.

I would start out with the PID gains that Centroid uses by default with every DC brush motor on CNC11 and CNC12 systems:
Kp = 1.0
Ki = 0.004
Kd = 3.0

If it tends to jitter or buzz while sitting still, try backing off to:
Kp = 0.6
Ki = 0.002
Kd = 1.2

... or something like that.

Let Centroid's Autotune set Kg, Kv1 and Ka. If Autotune sets an accel time less than 0.15 seconds, increase it to at least 0.20, and decrease Ka proportionally.

[Thinkin]

Thanks man. I watched a couple of PID tuning videos so I have some idea. I appreciate it.

[Thinkin]

Casual professional industrial use, but I’m just a 2 man show and it’s all in house prototyping and inventing not production work. And I still have manual machines to fall back on.

I basically decided to just try the servo motors from the advice I got from centroid, and if they shit the bed I’ll just order up the nice 15a motors from centroid.

No idea why you’d want an acorn over an all in one, this is a closed loop control system. 5k Encoders are upgraded too. And the swap is already done, I am just getting it going.

I have the wireless pendant so I have a manual jog. But I have a manual bridgeport to fall back on.

Understand.
I can't help but wonder if it wouldn't be better to replace/upgrade those old nearly 40 year old DC Servos. If you spend the money on All in One DC, and one of your motors dies, you are stuck with having to replace it with another DC brush Servo motor. Not a terrible deal.

Is this for home hobby use?
I assume the machine has no handwheels?
You might consider Acorn and some new AC Servos?

Marty

[martyscncgarage]

Casual professional industrial use, but I’m just a 2 man show and it’s all in house prototyping and inventing not production work. And I still have manual machines to fall back on.

I basically decided to just try the servo motors from the advice I got from centroid, and if they shit the bed I’ll just order up the nice 15a motors from centroid.

No idea why you’d want an acorn over an all in one, this is a closed loop control system. 5k Encoders are upgraded too. And the swap is already done, I am just getting it going.

I have the wireless pendant so I have a manual jog. But I have a manual bridgeport to fall back on.

Understand.
I can't help but wonder if it wouldn't be better to replace/upgrade those old nearly 40 year old DC Servos. If you spend the money on All in One DC, and one of your motors dies, you are stuck with having to replace it with another DC brush Servo motor. Not a terrible deal.

Is this for home hobby use?
I assume the machine has no handwheels?
You might consider Acorn and some new AC Servos?

Marty

Got it. You already have All in One. I see that now. At least you know All in One can control motors up to 40in-lb

Since Marc suggested they may be Baldor Servos, perhaps you can reach out to Baldor for specs on both motors.

Good luck on the project.

BTW, with an Acorn and AC servo drives/motors, the loop is closed by the AC Servo drive. You are correct however, Acorn is an open loop control. All in One DC or Oak are true closed loop controls.