Motor tuning issues

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bencarlson
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Re: Motor tuning issues

Post by bencarlson »

So, I learned a few things - first, the 90v to the Z-brake is applied as soon as the e-stop is released. This is fortuitous, since I forgot to jumper it. :)

Next, the z-axis is SIGNIFICANTLY smoother after switching the z-axis motor and encoder cables to the x-axis ports on the AIODC board. That being said, it still kicks out after a few runs as shown in the video below:

Titleiiarms
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Re: Motor tuning issues

Post by Titleiiarms »

Not sure if its possible on your setup but if it was me.. . I would figure out how to bypass the controller all together and supply motor voltage direct to the z axis motor and monitor the current while going UP on the Z axis. Im sure its a weight issue on that head compared to the X/Y axis or the head moving down with gravity. Eliminate the control/encoder/feedback issues and see if the motor will even go up and down when supplied with direct power. It should fly up and down.. :) Sure seems like a load/current issue supplying that Z motor.
Guy
Titleiiarms
Dilliner, PA
martyscncgarage
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Re: Motor tuning issues

Post by martyscncgarage »

Does the Z axis have its own pair of wires for the Z axis brake? If so, you should be using Output 9 to control the Z axis brake. You need to know the voltage of the brake. Usually +24VDC, and usually fed with its own power supply.

This way the brake is applied with power OFF, the control will close output 9 when motion is called for, either jog, home or MDI.

Perhaps you don't have the Z axis brake setup correctly?
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
bencarlson
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Re: Motor tuning issues

Post by bencarlson »

Titleiiarms wrote: Sun Sep 20, 2020 5:19 pm Im sure its a weight issue on that head compared to the X/Y axis or the head moving down with gravity.
Thanks for chiming in! If you review the previous posts and videos you'll see that the problem remains even with the motor disconnected from the z-axis head. It appears to be either a control issue or a motor issue at this point.

-Ben
bencarlson
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Re: Motor tuning issues

Post by bencarlson »

martyscncgarage wrote: Sun Sep 20, 2020 7:22 pm Does the Z axis have its own pair of wires for the Z axis brake? If so, you should be using Output 9 to control the Z axis brake. You need to know the voltage of the brake. Usually +24VDC, and usually fed with its own power supply.

This way the brake is applied with power OFF, the control will close output 9 when motion is called for, either jog, home or MDI.

Perhaps you don't have the Z axis brake setup correctly?
Yes, there's a separate set of wires for the z-brake. The z-brake requires 90vdc, which I'm supplying using a dedicated Antek power supply. Marc asked about my wiring previously - it's wired such that the 90vdc from the power supply is switched through a contactor wired to Output 9.

I'm going to review the z-brake wiring again, and try just hard-wiring the 90vdc to see if that solves anything. I had intended to do this, but ended up swapping the x & z axis wiring which didn't show much.

Thanks Marty!

-Ben
PXL_20200918_155545269.jpg
cncsnw
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Re: Motor tuning issues

Post by cncsnw »

Just releasing emergency stop should not release the brake.

Your PLC program logic will turn on the brake release (OUT9) whenever it sees that CNC12 has enabled the Z axis. CNC12 will only enable the Z axis when you first jog that axis, or when you start an automatic cycle (e.g. MDI, homing, running the PID collection moves, or running a CNC job.

You can use the Ctrl-Alt-F output forcing feature of the Alt-i PLC diagnostic display to confirm whether OUT9 indeed controls the brake. After testing with Ctrl-Alt-F, be sure to toggle it back around to PLC control (no underscore).

You can also use the Alt-i PLC diagnostic display to confirm that OUT9 remains red (off) after you release emergency stop, until you either press a Z axis jog button, or F3/MDI, or Cycle Start.
cncsnw
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Re: Motor tuning issues

Post by cncsnw »

In your most recent video, since you are using the PID tuning screen to test-run the motor, we cannot see what the error message was or where exactly the stall occurred.

However, since we are to understand that the problem happens with this motor, regardless of whether it is running off of the Z axis output or the X axis output, while the original X motor runs without problems on either of those outputs, we can probably safely conclude that the problem is with the motor. If it is not a case of the brake being inadvertently reapplied, then it is probably a winding or commutator problem.

You could monitor voltage across the motor brake circuit, or current through it, to see if there is any interruption just before the stall occurs. You would have to do that with the brake release jumpered or forced on, since it is a given that OUT9 will turn off immediately when the stall occurs.
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Re: Motor tuning issues

Post by martyscncgarage »

Ben Carlson,
Please post a new FRESH Report here. F7 Utilties, F7 Create Report.
I assume you get the stall error as soon as you try and move the Z axis?
I noted in your logs from the report three days ago:

(1) 09-18-2020 7:43:35 199 CNC Started
(1) 09-18-2020 7:43:35 CNC12-D Mill v4.12
(1) 09-18-2020 7:43:41 406 Emergency stop detected
(4) 09-18-2020 7:43:42 2099 Message Cleared
(1) 09-18-2020 7:43:42 412 MPG1 encoder error
(1) 09-18-2020 7:43:49 412 MPG1 encoder error
(1) 09-18-2020 7:44:33 SV_STALL ERROR Reported by CNC11!!!
(1) 09-18-2020 7:44:33 410 Z axis(3) position error
(1) 09-18-2020 7:44:40 406 Emergency stop detected
(1) 09-18-2020 7:44:40 SV_STALL ERROR Reported by CNC11!!!
(1) 09-18-2020 7:44:44 410 Z axis(3) position error
(1) 09-18-2020 7:44:44 SV_STALL ERROR Reported by CNC11!!!
(1) 09-18-2020 7:44:46 406 Emergency stop detected
(1) 09-18-2020 7:44:46 SV_STALL ERROR Reported by CNC11!!!
(4) 09-18-2020 7:45:35 555 Z Kp modified: 1.7293 -> 1.0000
(4) 09-18-2020 7:45:35 555 Z Kd modified: 3.2071 -> 3.0000
(4) 09-18-2020 7:45:35 555 Z Ka modified: 21.282511 -> 0.000000
(1) 09-18-2020 7:45:40 410 Z axis(3) position error
(1) 09-18-2020 7:45:40 SV_STALL ERROR Reported by CNC11!!!
(1) 09-18-2020 7:45:42 406 Emergency stop detected
(1) 09-18-2020 7:45:42 SV_STALL ERROR Reported by CNC11!!!
(1) 09-18-2020 7:46:23 411 Z axis(3) full power without motion
(1) 09-18-2020 7:46:23 SV_STALL ERROR Reported by CNC11!!!
(1) 09-18-2020 7:46:24 406 Emergency stop detected
(1) 09-18-2020 7:46:24 SV_STALL ERROR Reported by CNC11!!!
(1) 09-18-2020 7:47:45 Creating report...

I think I might unbolt the Z axis motor. Apply 90VDC to the brake and make sure the motor turns OK. And then while off the machine command motion to see if it turns. Seems like something is not quite right with the brake.

Marty
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
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bencarlson
Posts: 33
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Re: Motor tuning issues

Post by bencarlson »

So, I will have a report later today - I did a little messing around the past couple of evenings with a friend, and found that we might have a contactor issue on the z-brake - or the params for the z-brake are set incorrectly, so it's not releasing at the right time. Bypassing the contactor with 90vdc fixes things. :)

I'll report back my final findings, but I think I'm on the right track.

-Ben
bencarlson
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Re: Motor tuning issues

Post by bencarlson »

Here's the latest report file. I'm uploading a quick youtube video of the machine from this morning... you'll see it's working correctly with the z-brake jumpered, but you'll also see that the contactor is working properly. Not sure what that means... maybe the control isn't configured for the z-brake release?

-Ben
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