Replacing Advanced Motion Controls "brush type 12A8 with "Axcent" amplifier

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29 Oct 2020 22:42 - 29 Oct 2020 22:50 #187732 by OT-CNC

I have plugged power supply in to the wall and released e-stop, the software was in process of boot up and as soon as releasing e-stop x axis started jerking and red LED on AMC driver was blinking, so I quickly reset e-stop. Open to ideas. Many thanks!


I would start with a new clean configuration and test your encoder first without the motor connected to the table. You need to check the feedback loop is correct for both linuxcnc and the drive. Don't power up the motor. Spin shaft manually to see if it counts in the correct direction reflecting travel of tool. This is to prevent a runaway if the pid loop is reversed. Check to see if count increases when the tool travels in a positive direction in linuxcnc. Once the motor is powered, the pid loop may be incorrect in the drive which makes it easier to trouble shoot if you know that linuxcnc is correct then you can reverse it on the drive end.
See the configuration switch section of your drive pdf. SW1-6 , on/off to reverse.
Last edit: 29 Oct 2020 22:50 by OT-CNC. Reason: sp
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30 Oct 2020 13:54 - 31 Oct 2020 16:03 #187792 by new2linux
OT-CNC, many thanks for your help. I have clicked your karma "+" several times, but see no sign on your profile.
many thanks

Edit:
After using the Pncconf Wizard, I have saved a new version of the .ini & .hal files. Being that this is a 2 axis machine w/o spindle speed control and I don't want to use the 1 and 2 of encoder & drive inputs on the 7i77 card, is it better to start with a 2 axis machine (when using pncconf wizard) and edit (with text editor) or try to edit existing files with the wizard? There naturally several options in the wizard to pick from, is there a preferred way to approach or to think about it?

many thanks to all for the help, I am very grateful!

Edit01: I think set up for 5 axis but only use 3 (x,y &z). Edit after the wizard has worked so the x & y axis are with encoders 02 & 03 (at location TB3 & TB4) and just over look the areas that will not be used.

Edit02: I have went back to original .ini & .hal files, with wires under screw as per prior suggest, using the SW1-6 (this is AMC driver) to "off or on", did not allow x axis motor to stay w/o motion. There is no DRO with x or y axis. I was not shore how to proceed with Pncconf Wizard if I was not using the 00 and 01 address. I will be working on DRO.

Many thanks
Last edit: 31 Oct 2020 16:03 by new2linux. Reason: add question, & 2nd question

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02 Nov 2020 17:38 - 04 Nov 2020 14:47 #188126 by new2linux
Many thanks for all the help! I have reached out to A-M-C technician with the attached diagram to enable driver for Velocity control, and yes, this is correct, along with:

For velocity mode you need SW1-1 OFF, SW1-3 OFF.

The other switches are not mode dependent.

SW1-2 OFF for brushed motors

SW1-4 OFF for offset adjustment

SW1-5 sets the inhibit logic. If you don’t have anything connected to pin 9, leave it ON

SW1-6 sets the velocity feedback polarity, so it depends on how the encoder is installed and wired. It’s ON by default, switch it if the motor runs away. (this is set to off now, but motors w/o belt turn, POT 1 full CCW will not slow the RPM,)






Include the POT details included in the attachment:

POT1: Loop Gain Adjustment; In Velocity, Voltage, or Duty Cycle Mode, this potentiometer adjusts the gain in the velocity forward position of the closed loop. Turning this potentiometer clockwise increases the gain. Start from the full
counter-clockwise position, turn the potentiometer clockwise until the motor shaft oscillates, then
back off one turn.
POT2:
POT3:Reference Gain; This potentiometer may be left in the fully clockwise position if a
controller is used to close the velocity or position loops.
POT4:

I am not shore I am up to the task of using the Pncconf Wizard in addition to editor, as to allow not using the encoder 0 & encoder 1 (located TB3) and DRV 0 & DRV 1 (located TB5) for fear that the 7i77 may be smoked. If this is so then I need to order a new 7i77 card and get on with it.

many thanks
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Last edit: 04 Nov 2020 14:47 by new2linux. Reason: Correct Settings; 2nEDit; add POT details

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04 Nov 2020 15:27 #188316 by new2linux
Many thanks, tommylight, Todd Zuercher, JR1050, PCW, OT-CNC, the moderator: piasdom and all the members of the forum for the invaluable help. I fear I am at a loss and need some guidance, or suggestive reading to move forward. I have read the servo tuning by tommylight, and another by JT including Tuning LinuxCNC/HAL PID loops by John Kasunich.

This last "how to" by John Kasunich, describes how to turn motor w/o power to them by hand to test the encoders one at a time. When I click on linuxcnc to start, if the power to the motors is not "on" the screen will show (looks to be raw code error data) about 1/2 way down there is a debug about error so and so. If I power this up with "power to motors" the normal screen for linuxcnc (the logo screen) will load and I have access to the HAL Scope and the other HAL related meters. So curentely, the motors always turn (I have SW1-6 to help this but seems to do very little) and no motion on the DRO. The motors are not at such speed or torque that if you push on the end of shaft it will stop, but will feel motor jerking/serging when stopped. I have read in John Kasunich's tuning about and need to get to this part:
"Verify DAC outputs
Connect a HAL signal to the DAC outputs, set the DAC scaling set to 1.0. Then with motor/amp power off, set the HAL signal to 1.0 volts and verify (with a meter) that the output is correct. Repeat with -1.0 volts. Then verify with larger values, depending on the range of the DAC, for example 5.0 volts, and -5.0 volts."

All help is warmly welcomed, I am just at the point where I am not shore of the area that needs to be addressed 1st. The only thought I have is that the leads that enable driver for Velocity control, are affecting the other settings, and maybe disconnect until after some of the other setting are set. Or the 7i77 card needs to be replaced.

Many thanks, all help warmly welcomed.

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04 Nov 2020 17:00 - 04 Nov 2020 17:03 #188324 by Todd Zuercher
There are two essential wiring requirements that you must have working correctly before even attempting to tune or even power up the servo drives. The first is the drive enable signal. Your wiring diagram above doesn't show it being connected. It would be connecting pin#9 on the AB15A100 drive to TB5#2 on the 7i77 card then TB5#1 on the 7i77 card back to pin#11 (ground) on the drive. (Also dip switch SW1-5 should be set to OFF on the drive.) It is essential that the polarity of this connection be correct on the 7i77 card or the chip on the 7i77 can be ruined. If you have accidentally already ruined the enable output for that drive on the 7i77 card, you can use one of the other unused enable outputs (they are all switched together anyway) or set up a relay and control it with one of the regular field outputs.

The 2nd thing you must have working is the encoder feed back. And here I am very confused by what you say you have and the photos of what you did have. Your initial photos and your drawing shows that you have(had) 6 wires connected to the 7i77 encoder input orange, red, grey, green, violet, and black. But then you reference a US Digital pigtail CA-LC5-W4-NC that only has 4 wires. Did you change encoders for some reason? I'm just not sure what you actually have going on.

For the 4 wire encoder you would move the jumpers on the 7i77 for encoder0 to thier single ended setting. Jumper W19 and W21 should be set to the left side (default was to the right). But if your encoder is in fact a differential one with 6 wires you should leave the jumpers in their default positions.

Does the encoder feedback work? (When you turn the encoder does the DRO change?) Does it work if the leads are connected to pins 6 and 7 of the drive? If not does it work when they are disconnected? You might also need to connect a wire from pin #11 on the drive to TB3#1 on the 7i77.

If you were trying to start Linuxcnc with the drive powered off and Linuxcnc failed to start, the most likely reason is that something you did to prevent the drives from powering probably also removed one of the power sources from the 7i77 card. But I can't say for sure without seeing the debug message or knowing more about exactly what you did.

It is ok for the drive to be powered when Linuxcnc is not in control as long as they are not enabled. (back to that pin#9 connection on the drive) If they are not enabled they will not be powering the motor.
Last edit: 04 Nov 2020 17:03 by Todd Zuercher.
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04 Nov 2020 17:52 - 04 Nov 2020 18:22 #188330 by AdvancedMotionControls
Hi new2linux,
Forgive me if I'm asking about something you may have already configured, but my first concern would be to make sure the servo drive is actually enabling. The 12A8 is for brushed motors, while the AxCent may be for brushed or brushless depending on what model you have. My assumption from the title is you've replaced the drive but not the motor, so your system currently consists of a brushed motor with possibly a brushless servo drive.
All of our brushless drives can drive brushed motors but there's a little bit of configuration to get them to enable.
Just chiming in to make sure you've eliminated any easy fixes on the servo drive side, and I'd be happy to help with any drive problems.

Edit: I didn't realize this topic was 7 pages long! My apologies if I'm jumping in well after the fact.
Last edit: 04 Nov 2020 18:22 by AdvancedMotionControls.
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04 Nov 2020 18:43 #188334 by OT-CNC
AdvancedMotionControl

Welcome to linuxcnc and thanks for offering to help!
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04 Nov 2020 18:47 #188335 by Todd Zuercher
I guess that is another assumption we've made, that you have properly configured and connected the drive for use with a brushed motor.
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04 Nov 2020 19:02 - 05 Nov 2020 14:27 #188337 by new2linux
Todd, many thanks for you help. I am working the 1st paragraph including pin 9 issue as per your suggestion. The encoder: www.usdigital.com/products/encoders/incr.../modules/EM1-2-500-N is new and the jumpers on 7i77 are moved to the left, because the new encoders are single ended encoder signal. The earlier diagram shows a pictorial representation of the original protrak round connector on back of cabinet with its colors. The newer diagram is w/o the round plug. The address are on the connectors to show from & to info.
Encode does not move DRO. I will be working pin 9 & 11 issues. many thanks!!

AdvancedMotionControls, Many thanks, for your thoughts. The project is 2 axis mill and DC brushed motor application. Please advise.
Many thanks

Edit:Attached is a pic of the debug info when 1st start up w/o power to motor, with the pin 9 & 11 connected to TB5 (positions 1 & 2). This also has 6 & 7 connected to TB5, as in earlier post. When I power up motors & restart linuxcnc, I get logo screen, the motors are in motion. As per suggestion SW1-5 is off (all SW1-1 to-6 is off). DRO does not move.

As per Todd's suggestion: . If you have accidentally already ruined the enable output for that drive on the 7i77 card, you can use one of the other unused enable outputs (they are all switched together anyway) or set up a relay and control it with one of the regular field outputs. This is TB2? Pick a different location use 1 through 4, like 2?
many thanks!
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Last edit: 05 Nov 2020 14:27 by new2linux. Reason: Edit:Debug Pic

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05 Nov 2020 17:29 #188413 by new2linux
Many thanks for all the help. I have used TB2 2 (the old one was 1) because I may have accidentally ruined the enable output for that drive on the 7i77 card (If this is not ruined, I will go back to use 1). This did not change the motor turning as soon as power up and linuxcnc is running. The DRO does not move, no motion on the screen, like the yellow path (use Ctrl K to clear). Pins 4,5,6,7,9,& 11 are to TB3 or TB5. I have reached out to AMC through email support.

Many thanks, all help warmly welcomed!

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