Little Monster -s hort to ground
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@infamous_panda said in Little Monster -s hort to ground:
M350 X16 Y16 Z16 E16 I0
You'll need I1 to enable interpolation.
https://duet3d.dozuki.com/Wiki/GCode#Section_M350_Set_microstepping_mode
You could also experiment with S2 and S3 to switch between spread cycle and stealth chop respectively.
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@phaedrux Yeah, I did have those turned on at one point or another. Right now I'm just shooting for "working". I can hold off on microstepping and interpolation.
32 was just a carry over from my old board and really with 0.9 deg steppers it's overkill for my needs. I want reliability, speed, and accuracy in that order. Surface finish and resolution are not too important.
I think I am getting somewhere setting the machine at 1050mA and lowering the speeds. Which is a bit of a bummer but at least it's way quieter.
What I suspect is that the short to ground error is being misreported. I mean a short should be present or not and immediately apparent once the motors are energized. Not happen minutes or hours into a print. Apologies if this shows a lack of electrical engineering knowledge.
It really needs to be a feature for the Duet to stop a print once a short-to-ground occurs AUTOMATICALLY. Because on a DELTA if you are not watching closely, the remaining axis motors will start flailing around and crashing into things. I suppose this can go on for hours causing real damage. It's been a real PIA working on this problem because I have to be present for the duration of any test.
Sorry Ranting.
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@infamous_panda said in Little Monster -s hort to ground:
I can hold off on microstepping and interpolation.
I Wouldn't hold off on interpolation. I think it's generally a good idea because of how smooth it makes the motors run.
What is the rated current of your motors? Generally setting the drivers to 80-85% of rated is recommended provided cooling is adequate. In your case that may mean at least guaranteeing some air flow over the bottom of the board. Perhaps you already are.
I'm not an electrical engineer either, so I can't speak to the short to ground state. But I'm going on the premise that eliminating any other factors will either cure the symptom or narrow down the problem.
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@phaedrux Thanks man, Giving up for now. M3D has agreed to look at the board.
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@infamous_panda said in Little Monster -s hort to ground:
I think I am getting somewhere setting the machine at 1050mA and lowering the speeds. Which is a bit of a bummer but at least it's way quieter.
I have found that stealthchop mode is way noisier at high speeds. Switching to spread cycle mode makes it much quieter at high speeds. In either mode, both types of motors I tried are silent at rest and quiet at low speeds.
What I suspect is that the short to ground error is being misreported. I mean a short should be present or not and immediately apparent once the motors are energized. Not happen minutes or hours into a print.
Exactly. But as the fault only shows up after some time, I suspect it is temperature-related. The chip evidently thinks there is a short to ground or over temperature situation, because it is shutting off the output, causing steps to be lost.
Duet WiFi hardware designer and firmware engineer
Please do not ask me for Duet support via PM or email, use the forum
http://www.escher3d.com, https://miscsolutions.wordpress.com -
@rafb
Here my Duet Wifi files.
I had to cut the bridge on my BL touch for 3.3V.
https://www.thingiverse.com/thing:3052203/files -
Perhaps the temperature sensing function is buggy on the Maestro since it does not show anything on M122? However your test did report the temperature error, did it also turn off the motor or report short to ground?
Something to note, during my first few power ups I had the default speeds copied from my smoothieboard (very high) and the current set to 1.5. The board would report short to ground on all axis the second I tried to home.
So the maestro is stated to support 1.6 amp but apparently this is still under testing? If I have to go below 1 amp for reliability how much should I expect to decrease speeds when compared to my smoothieboard running at 1.8 amps?
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@autsch So it looks like you are running the machine as fast as you were when it was stock?
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@infamous_panda said in Little Monster -s hort to ground:
Perhaps the temperature sensing function is buggy on the Maestro since it does not show anything on M122? However your test did report the temperature error, did it also turn off the motor or report short to ground?
In my tests, the over-temperature warning was reported by M122, but not to the console as popup warning messages. I have found the cause for that and I am working on a 2.02beta2 release. I didn't let the drives get hot enough to give over-temperature shutdown.
Something to note, during my first few power ups I had the default speeds copied from my smoothieboard (very high) and the current set to 1.5. The board would report short to ground on all axis the second I tried to home.
That's interesting! I think this is either an issue with using stealthChop mode at high speeds (which Trinamic says on the data sheet may not work well), or else your motor cable capacitance is very high and the blanking time parameter in the chopper control register needs to be increased because of that. Have you tried using spreadcycle mode? To select it on driver 0, send M569 P0 D2. Repeat for P1...P4. With the motors that I tested with, it was quiet at all speeds; but I am aware that spread cycle mode can be noisier than stealthchop with some types of motor.
If that doesn't help then I can give you the chopper control register values to increase the blanking time.
So the maestro is stated to support 1.6 amp but apparently this is still under testing? If I have to go below 1 amp for reliability how much should I expect to decrease speeds when compared to my smoothieboard running at 1.8 amps?
The firmware limit and design goal is 1.6A. My tests indicate that 1.0A on 4 drivers works without any cooling at all, and 1.4A works with minimal fan cooling. With a properly-designed enclosure with a fan that blows air along both top and bottom of the Duet, I think 1.6A should be achievable.
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@infamous_panda
I dont care about speed
My next mods are Plexi Cover, 0.9 degree steppers, smart effector with mag balls, linear rails and a flexi drive direct Extruder.
I allready have the parts, but it takes time...
