Set up using AMC AB15A100 drives, brushed DC motor Prototrak Plus with Encoders

Todd, Yes DRO is correct, if I count off the 5 turns of the handle. Did it have a feed rate of 60"/min, I don't know.
Pot1 with sw3-factory will only go to around 8.5 & pot3 around 7.625, see pic the pot3=6 is motor jerks & pot3=7.625 no jerk.

Many thanks

In post #246156 according to the names of your images you had pot1 set to 12.0 , and those were by far the best tuning you've showed, and the 4th image shows the best of those.
forum.linuxcnc.org/media/kunena/attachme...pot36.0ReDoNoOsc.png
In that image the axis is only moving at 0.5ips (30ipm). Is it possible that is all the faster the machine used to be able to go? I think you may be running into the speed limit for your system as it is configured.

Try using only a 20ipm jog speed for your test jog and see if you can turn down pot 3 so the encoder velocity matches the commanded velocity at that speed.

A couple of question about your system. What is the rated voltage and rpm for your servo motors? What is the voltage of the power supply feeding the servo drive?

 Todd, thanks! The drives receive 38VDC. The motor spec sheet is attached. A-M-C's engineer has just asked the same question.

Many thanks!


 

Follow that up with what is your screw pitch and/or encoder counts/rev.?

About 1000rpm is about all the faster your set up can spin. (not sure the what that equates to in ipm without knowing the screw pitch.)

Todd, many thanks! The ball-screw is .200/rev. Encoder count is 500 (accuracy 2000). The trace at 20"/min is attached.

A-M-C engineer suggest " workaround would be to lower your target velocity, or to use a suitable power supply for the motors rated voltage of 60VDC."

If I can get close is OK.
As you view the trace, look at the very start and end, the motors are on the thin edge of buzzing/unstable.
Many thanks!

I have a A-M-C model PS2x300W, power supply, will this help my situation?

Edit: The pulley on motor has 16 teeth: the pulley on ball screw has 44 teeth.
 

We are doing what the AMC engineer is suggesting, by using 20ipm for the jog (target) velocity. Now try adjusting pot3 to get the purple trace up to the other two.

Yes using a higher voltage supply will increase the max speed, but if my calculations are correct, 38v "should" be able to turn it close to 70ipm.
Did you ever replace the power supply? Is your power supply actually supplying 38v, even under load?

Earlier posts of your ini file show 27500 encoder counts/inch, and another post says you have a 0.2" screw with 16:44 belt reduction. That equates to a 2000 count/rev (500 line) encoder. From that we can calculate that at 0.5ips, the motor is turning at 6.875rps or 412.5rpm. With the motors spec V/krpm constant of 34, we can estimate that the motor is probably only seeing about 14-15v.

Todd, I need to ponder your post some more, but I have 2 of the power supplies that look exactly alike (plus the A-M-C one), I have not changed power supply. I will try tuning to pot3 to get it closer. I should leave POT1 as high as it will go & not oscillate & not so low making the motor jerk? Work POT3 so traces get as close as possible unless other posts suggest different.
Many thanks!!

Edit: I have not verified the power supply is working under load. I will see if I can read meter and push the buttons for jog.
Edit00: The volt meter while jogging at full 60" or at shower feed rate shows meter at low as 35.5 Volts DC.

If we can get it tuned at 20ipm, and you are satisfied with only having a max speed of 40, 50ipm or what ever speed we find is the practical limit, then we can change your configuration to use that speed as the max,.

Have you done anything with pot2? Do you know where it is currently set set? Grasping at straws, but could the current limit of the drive be getting in the way? (I only ask not having a clue how the current limit in this drive behaves. Most of the drives I've worked with will shut down, set an alarm and disable the drive when the current limit is hit, so if it behaves that way it couldn't be the problem.)

Todd, Thank you so very much!! I am OK with what we can get. Pot2 is at 11 turns, as per calculation with A-M-C in the loop, I can verify, or tweak. Attached are traces as best yet, 1.5 units separation. The pot3 traces are only vary 1/16 of a turn. These traces ARE IN units 50m/unit, from all others!!!!
The used A-M-C power supply, will not help with this application, as per A-M-C.
Many thanks!!
 

Getting better, still looks like you need another full turn on pot3, maybe a little more.

After you get it lined up you'll probably should to adjust pot1 a little more, to clean up the overshoot spike.