TinyG UGS Power Supply Stepper Motor Strange Phenomenon

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aidenwolf
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TinyG UGS Power Supply Stepper Motor Strange Phenomenon

Post by aidenwolf » Wed Jan 20, 2016 7:27 am

I've been running jobs with my S02 with TinyG and the UGS V1.09 (For TinyG) very well lately with no issues at all, but last night I ran a job where it starting cutting like normal then stopped 1/4 way round the first Z-cut.
It didn't miss steps and I was able to jog the machine in all directions, it just stopped. (nothing wrong with the G-code as far as I could tell, or the TinyG settings). So I turned everything off and restarted TinyG and UGS and chose a new machine Zero on the workpiece and ran the same gcode, and it did the same thing again only this time stopped in a slightly different place to the first time.

At this point I got quite angry because I didnt know what the issue was, and was completely different problem to the reliability issues that has plagued me since the beginning. Anyway I turned all the power off in the garage and went out, several hours I returned to the scene of the crime and with no ammendments made I ran the same gcode again and it worked fine, no issues, no stopping, nothing, just worked as it should.

The only thing I can think that may have caused this problem is, before I turned the power supply on to the SO2 I manually moved the gantry's out of the way with my hands to place a new workpiece on the bed and as I moved them the tinyG's lights all flickered on and the fans all started spinning round - despite the power supply not being on. It's like as I moved the gantry it forced the steppers to spin round and act as a dynamo and power up the TinyG and fans. Also doing this maybe it scrambled something in the TinyG which caused my initial problem, and when I reset the power in the garage it reset the TinyG and is now OK.

Is this possible?

WillAdams
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Re: TinyG UGS Power Supply Stepper Motor Strange Phenomenon

Post by WillAdams » Wed Jan 20, 2016 11:49 am

Yes, the stepper motors functioning as generators is an observed and commented on behaviour.

In robotics moving a robot is strongly discouraged, pretty much forbidden. While there have been cautions on this here, no prohibition, assuming that the controller and stepper driver handle higher voltages during operation.

Maybe we should not do that.

We should figure out where to put it on the wiki though: http://www.shapeoko.com/forum/viewtopic ... 324#p49305
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cmcgrath5035
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Re: TinyG UGS Power Supply Stepper Motor Strange Phenomenon

Post by cmcgrath5035 » Wed Jan 20, 2016 12:02 pm

Steppers as generators is almost impossible to avoid; I do it all the time and have not observed issues.
That does not mean it is a great idea.

What FW is running on your tinyG?
Do you have limit switches? NO or NC?
When tinyG stopped, any active LEDs?
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aidenwolf
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Re: TinyG UGS Power Supply Stepper Motor Strange Phenomenon

Post by aidenwolf » Wed Jan 20, 2016 1:08 pm

Yeah, will try to avoid moving the gantry around by hand. Didn't realise they would turn into a generator!

Not sure what Firmware I'm running, its whatever the TinyG came with, cos I haven't updated it. Just the general settings for motors etc... I'm at work at the moment so can't check.
The limit switches are disabled in TinyG. They are present and wired up in my machine (just not to the TinyG), I haven't used them as my bed is approx 1000 x 1500 and the jobs I've ran have been nowhere near the extremities of my machine to really use them.
To be honest I have no idea what lights were on the TinyG when it stopped, all I know is I didnt turn the power off or disconnect from UGS, but when I went to jog all the axis (to give me a clue whether it was something to do with wiring) they all moved OK.

I'll run something tonight, hopefully it continues to be OK.

cmcgrath5035
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Re: TinyG UGS Power Supply Stepper Motor Strange Phenomenon

Post by cmcgrath5035 » Wed Jan 20, 2016 1:19 pm

From UGS enter $$ command, copy the parameters to a cloud file and post the URL for a look.

The most up to date FW is $fb=440.20

If tinyG "thinks" a limit switch fired, it stops and the SpinDir LED flashes quickly.
Only way to recover from that is reset button (or Power cycle tinyG.
Noise spikes can fire unterminated or unshielded limit switches.
ShapeOko (V1) SN 1462
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TinyG V7 Controller; DUE and tinyGV9 test bed for tinyG2

aidenwolf
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Re: TinyG UGS Power Supply Stepper Motor Strange Phenomenon

Post by aidenwolf » Thu Jan 21, 2016 11:28 am

Yes think your right, either way resetting the power to TinyG probably fixed it.
No issues running something last night.

AnonymousPerson
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Re: TinyG UGS Power Supply Stepper Motor Strange Phenomenon

Post by AnonymousPerson » Thu Jan 21, 2016 8:18 pm

WillAdams wrote:Maybe we should not do that.
If Carbide Motion wasn't so awfully damn slow when jogging, that might be feasible. Until that's fixed, people are going to move the gantry by hand. ;)
Shapeoko 3 #516

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