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Author Topic: IP-A and Servo drives, voltage matching...  (Read 9134 times)

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Offline mc

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Re: IP-A and Servo drives, voltage matching...
« Reply #10 on: November 09, 2016, 06:19:56 PM »
The default drive tuning for the selected motor should be pretty good on modern digital drives. I know trying to tune my drives didn't make much difference to the end result. Depending on what mode you're running the drives in, depends on just how much the drive tuning affects thing. Torque mode at most you'll get some input filtering, Speed mode you'll also get a bit more tuning to ensure the speed is stable, and Step/Dir mode the full tuning in the drive is used.
What CS-Labs will be referring to is older amplifiers, where you had to manually tune the amplifier to match the motor, otherwise you ended up trying to tune the PID loop with an already unstable motor/amplifier.

I'd try adjusting the PID loop in the IP-A as per the instructions above, and see if you can improve things.
I'm not sure how you test moves with the IP-A, but the KFlop software gives you the option to quickly edit the settings, then command a back and forth move, at which point a plot is displayed, so you can see almost instantly how things have changed. It is wise to have your hand over the E-Stop though, just in case you trigger some big oscillations (been there, got the medal, and even managed to overheat the motor!)

Offline Davek0974

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Re: IP-A and Servo drives, voltage matching...
« Reply #11 on: November 10, 2016, 02:18:19 AM »
Thanks, that does make sense, we have some older machines at work with manual drives and they had to be tuned properly so i think i know what type you mean.

I will revisit the tuning this weekend and see what happens.

The Flop sounds very similar - the CS-Labs have a graph and easy to set variables so its not too hard to do - the hard part is knowing what to look for and when to back off.

Also what speed do you tune at?

Needs a concise write-up i think, should help many users - any takers???

:)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline mc

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Re: IP-A and Servo drives, voltage matching...
« Reply #12 on: November 10, 2016, 04:24:49 AM »
Ideally the tuning move should reach the maximum speed the machine will run at, however you should gradually work up to that when tuning, just to avoid causing any prolonged wild oscillations if a change in PID settings makes things badly unstable.

KFlop lets you do two different types of moves. A block step move, and a move limited by the Velocity, Acceleration, and Jerk settings.
The block step is an instantaneous command (i.e. Acceleration and Jerk settings are ignored) to move the requested position amount, which you use to determine just how quickly the system can accelerate, and how quickly it can handle peaks in command, but it's brutal on the machine.

The VAJ limited move is more like a move you'd command during G-Code running, which is what you use for normal tuning.

What you're looking for when tuning, is for when things become unstable, then backing of a bit.
Ideally after sudden change in requested position/speed, there should be a short peak in output, which should quickly settle down with minimal oscillation.
If you have no peak, then the output isn't being driven hard enough, and you're following error will most likely jump up until things catch up.
If you have a peak, that is followed by endless oscillations, then best case scenario the following error can be pretty low, but the servo will be continually oscillating to stay on position, and in the worst case, the servo will be wildly oscillating with a huge swing in following error.
You're aiming for a compromise between the two.

And I've just remembered there's a guide on the Dynomotion wiki - http://www.dynomotion.com/wiki/index.php?title=Main_Page#Axes_Servo_Tuning_and_Trajectory_Planner
Some of it won't apply, but the underlying process will be very similar.

Offline Davek0974

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Re: IP-A and Servo drives, voltage matching...
« Reply #13 on: November 10, 2016, 05:41:47 AM »
Thanks,

i had a look at the link but the terminology is totally different so could not apply it to my system.

I will re-read the earlier posts and have another play this weekend hopefully.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: IP-A and Servo drives, voltage matching...
« Reply #14 on: November 13, 2016, 08:32:09 AM »
Spent a good few hours this morning playing with tuning, did not get any further forwards or any improvement over where i was at the start.

I can get it the oscillate, vibrate, overshoot etc but its all speed relative - tune slow, will not run fast, tune fast will not run slow.

There seems to be a massive amount of contradiction on tuning as well - the CS-Labs manual says tune P first then add I, earlier in this thread I was advised tune P first then D.

I have tried both, D seems to very little.

In the end i pushed P until i got oscillation at a certain speed, checked it at various speeds then backed it off, the added I until I saw no further improvement in following error, then tweaked it with a little Kvff. So its back to where I was before, I cannot get following error below about 380-400 on this axis (X).

I can't find any videos either - it must be specific to CS-Labs controllers or it makes no sense.

Auto-Tune is terrible - very poor rigidity and pretty poor following error too.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: IP-A and Servo drives, voltage matching...
« Reply #15 on: January 31, 2017, 03:25:04 AM »
Greetings Davek 0974

Have you solved the problem? I have  some similar problesm with the asuto tuning. I have  new motors servo motors and drivers from kinco, also the linear scales are new  Iskra. I have tied the auto tune
but it simply does not work properly. I'm starting to lose faith in the csmio controller.

Before changing the motors i have used the original bosch driver and dc motors and i have managed to tune them porll. But there was another problem as soon as i pushed the button go to zero and after that stop
the machine started to go in some kind of a auto tune state.  I have contacted the spupport  and they have said i should send them the mach file. Now its about 4 months and still no answer.

So im a litle disapointed.


Best regards

slovenec
« Last Edit: January 31, 2017, 03:26:37 AM by slovenec »

Offline Davek0974

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Re: IP-A and Servo drives, voltage matching...
« Reply #16 on: January 31, 2017, 03:29:36 AM »
Hi

I did not get anywhere with autotune, i just played with the numbers until i felt it was working ok

I have no doubts it could do better but would need a specialist i think in servo drives.

I would send CS labs your email again, I have never found them to be slow to reply and the product is excellent, it is my knowledge in tuning what is an advanced piece of industrial control equipment that is lacking.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: IP-A and Servo drives, voltage matching...
« Reply #17 on: October 03, 2018, 05:58:26 PM »
Hi,

I have a DM-26EA servo drive however I can't find an English manual for it (came with a manual in full Chinese). The drive looks identical to the ASDD-30A.

https://www.aliexpress.com/item/Best-price-great-quality-Servo-motor-set-6-N-M-1-8KW-3000RPM-AC-110ST-M06030/32423941086.html

Do you think I can use the ASDD-30A manual for my DM-26EA?

Offline Davek0974

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Re: IP-A and Servo drives, voltage matching...
« Reply #18 on: August 20, 2019, 05:37:00 AM »
Possibly, look at some of the values and compare to the manual, if they seem sensible or similar then it might be ok. The supplier should provide a link though.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives