A-M-C A12A100 Servo Drive with SouthWestern Ind ProtoTrak Plus
Edit, Should I also think about the amp rating? The original 12a8 drives had all power I was in need of. It may help if I had a accurate description that was short in length to describe the primary issue: This is from earlier post by "PCW" it as I know it as to use the following to insure full 10 volt is going to drive:
"You can check that the analog +-10V outputs function properly by first disabling the drives
then launching LinuxCNC and running these halcmd commands in a terminal:
halcmd: delsig x-output
halcmd: delsig x-enable
halcmd: setp hm2_5i25.0.7i77.0.1.analogena true
halcmd: setp hm2_5i25.0.7i77.0.1.analogout0 10
(check for +10V on 7I77 analog out 0)
halcmd: setp hm2_5i25.0.7i77.0.1.analogout0 -10
(check for +10V on 7I77 analog out 0)
note that the "halcmd:" is a prompt printed by halcmd, not something you should type
Do you have your motor specs? 6.25 A peak sounds quite low "
The full 10 volt was delivered to drive, and insufficient voltage was delivered to motor?
This is the quote:
"All that to say, I think you could use a single-ended encoder
directly, and bypass the circuit board with the DS8830N chip on it, it
doesn't sound like you need it at all. We do have a similar device,
that converts single-ended to differential, but it looks like it may
be unnecessary. I can provide a list of part numbers to do this either
way, completely single-ended, or with the differential line driver
added, it's up to you."
If there is any possibility this will fix and is a stocked item, I will buy them. I will try to get a picture attached. Many, many thanks for the help.
position errors after many moves as measured by a dial gauge. there is no reason
to be concerned about the encoder connections.
Edit: I have reached out to the AMC and was assured that this drive will work as advertised. Is there any chance that I have just not noticed the preferred tuning adjustments or wrong sequences in the method? many thanks!
Edit01: Is this a formal name or is there a different name for: "back EMF as a form of feedback for velocity control"? I have refereed to this "back EMF" as encoder input. Is this encoder input or is there another name or term that is used? many thanks, just trying to understand better.
Todd, If your offer is still available I would be very grateful for any help, with the understanding, at your convenience. Attached are the .ini & .hal files that I use. many thanks!
I did not get diagram correct as to 7i77 card (TB5) pin 3 GND needs to go to location 4 +REF IN on the A-M-C drives (P1) signal connector and (TB5) pin 4 AOUT0 needs to go to location 5 -REF IN. It is my belief this is the issue that has always been an issue, only recently was resolved with the a12a100 diagram (this current post).
The rest of the story is that the drives ab15a100 at this post: forum.linuxcnc.org/12-milling/39963-repl...t-amplifier?start=60
The ab15a100 drives have a place on P1 (signal connector) on the drive (no separate P3 connector) for encoder input, pin 2 Signal GND, pin 6 Encoder-B IN & pin 7 Encoder-A IN. I am thinking to ask for exchange, to go back to AB15A100 for the encoder input.
I believe I should go back to the prior posts and edit the 1st page (at the start) and attach a good diagram and say to use this new diagram.
I deeply regret my error and will try to edit other post so others will have a chance with success. Suggestions welcomed.
An encoder is a physical device that senses position. Here's a description and some images: en.wikipedia.org/wiki/Incremental_encoder - The second image shows the insides of an optical encoder, with a thin steel disk with slots etched into it and an optical reader that detects the slots.
new2linux wrote: Edit01: Is this a formal name or is there a different name for: "back EMF as a form of feedback for velocity control"? I have refereed to this "back EMF" as encoder input. Is this encoder input or is there another name or term that is used? many thanks, just trying to understand better.
Back-EMF is a property of electrical motors which can be used to sense motor speed. See e.g. en.wikipedia.org/wiki/Counter-electromotive_force "In motor control and robotics, back-EMF often refers most specifically to actually using the voltage generated by a spinning motor to infer the speed of the motor's rotation, for use in better controlling the motor in specific ways."
Tuning this, first you must tune the inner velocity loop. Do this by sending an open loop step command to it. The easiest way is to just set all of the position loop constants (P, I, D...) to zero except for FF1=1. then command some short moves. (A better way might be to set up a square wave siggen connected directly to the pid.x-vel.command but that is a lot of temporary hal configuring to do.) Increase the VEL_P to get the velocity feed back to most closely follow the commanded velocity without overshoot or oscillation (minimize the rize time). adding VEL_D if it helps with any oscillations. It is important that this is smooth without oscillating. After you are mostly happy with that. Then tune the position loop PID and FF terms following the instructions in the normal servo tuning tutorials.
File Attachment:File Name: 2pid.hal
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File Attachment:File Name: 2pid.ini
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