Follow error

[Lotusjohn]

I am using Sanyo P5 motors 400wt. These were absolute encoder motors. I have removed the absolute encoder and installed a CUI Encoder (Digikey 102-1308) set to 2048 PPR.
I had some dither issues with the motor during tuning and came up with the following settings. All the curves look good.

Torque P gain 5200
Torque I gain 325
Tq Freq 1000hz

Position PIV
P gain 600
I gain 300
Follow error 1000

Dither—Changed enc count to +/- 10

Velocity
P gain 300
I gain 200
Follow error 200

When I try to get Mach3 to move the motor, I get about 2 ½ turns at
~ 50rpm before a follow error. I have doubled to the follow error on both Position and Velocity. I have tried halving the above P gains (pos & vel) and it makes no difference.

Suggestions ??

John

[Al_The_Man]

Encoder phasing?
(Counting in the opposite direction)?.
Aren't the P5 AC motors, if you changed the encoders, what did you do about the commutation?
Al.

[Lotusjohn]

Yes, The P-5 is an AC servo
Unless I am understanding this wrong, the VSD-E should be able phase via the encoder. A hall device is not required. I have is setup to phase with 1000ma

[Montabelli]

what is the response on the test motor section of the set up? is the count and phasing accurate? if there is an issue with the encoders it should show up here i think. you are correct about the hall sensors I am running fanuk red caps with these drives. are you running a vesdepi and mach 3 or another controller? I had all kinds of problems running with mach3 at first all my problems were issues with windows itself.

[Lotusjohn]

The test motor on the setup works. I am trying to run VSedpi and Mach3. What windows issues did you have ??

John

[Montabelli]

the symptom I had was sudden stopping and starting in motions. a big klunk, and then continued motion, even single axis motions. They seemed pretty regular timing wise, and I was able to stop that by cutting back on the resolution through the multiplier. some of the sudden stops were enough to cause follow errors. Since I wanted the maximum resolution the machine had to offer, 1k steps per mm, I decided to get a smoothstepper. that has taken care of most issues. I tried to optimize windows, but I just messed it up so badly that I had to reinstall it.

[Lotusjohn]

It looks as though I have found my problem. With a signal generator, I found that the problem was either the servo drive or the motor. I eventually changed to encoder CPR to 500. Re-tuning the motor was required. After that everything appears to work. The motor moves with simple Mach3 commands.

John