E3D Roto + Duet Roto Toolboard - Stepper motor stalling

dc42

@arturolaz those temperatures look OK. I'm wondering whether the grounding between the tool board and the extruder motor body may be missing. If you have a multimeter, try disconnecting the tool board connector and measuring the resistance between the VIN ground pin on the tool board and the stepper motor body. It should be 50kohms if both mounting screws are connecting.

arturolaz

@dc42 My bad, there is no connection between them as the way I created the fan shroud requires the mounting screw not touching the toolboard but instead coming from the shroud. I have now read the wiring notes from the docs and will be trying it.

How can this cascade to a motor stall?

dc42

@arturolaz extruding filament builds up static charge. If it is allowed to build up on the extruder motor body, it may flash over to the stepper motor wires. From there it flows into the stepper motor driver and may trigger the short circuit detection in the driver.

See also this thread https://forum.duet3d.com/topic/37882/extruder-stopping-mid-print-fixed-after-reboot.

arturolaz

@dc42 Understood. I did the test grounding the metal body of the Roto through a wire soldered to the V- terminal of the power connector in the toolboard with a 100k serial resistor but it didn't work, it failed just like before even without reaching 70C

arturolaz

@dc42 I've been reading about CoolStep and I think it is the next step, unless you have another idea for me to try before.

Are there any special considerations when implementing CoolStep for the extruder? Most of the documentation is oriented for the other motors

arturolaz

I haven't been able to conrrectly configure stall detection for the extruder, I just found this post from some years ago https://forum.duet3d.com/post/102570 so I'm running out of options if CoolStep can't be implemented...

dc42

@arturolaz I doubt that CoolStep is the solution because I am not convinced that the driver is overheating. How quickly after the driver stopped extruding did you take the M121? If the driver really is shutting down because of overheating then it will cool down fairly quickly.

BTW your M121 report says that the driver on the tool board is stalled:

Driver 0: pos 0, 2682.0 steps/mm, stalled, SG min 0, temp 69.9C, read errors 0, write errors 0, ifcnt 52, reads 40354, writes 0, timeouts 0, DMA errors 0, steps req 0 done 251658

If you haven't set the stall detection threshold using M915 then that doesn't necessarily mean that it has stopped moving, but it does suggest that it was under high load when last commanded to move.

arturolaz

@dc42 I sent the command as soon as I realized it was failing, 2minutes difference top, at that point I hadn't enabled anything related to stall detection.

Quick update of my tests:

Disconnected the Roto motor from the Roto toolboard and rewired it to use a Duet3 stepper driver - Still failing
Printed the exact same test print but now with PLA hoping that the ABS ambient temperature was the trigger of the motor failure but it also failed
Inspected the whole motor assembly but found no issues apart from maybe insufficient grease on the gears (waiting for the grease to test)

At this point I'm almost sure the motor or some configuration is the problem but I can't find the root cause of it

dc42

@arturolaz what mode are you running the driver in? Send M569 P121.0 to check.

arturolaz

@dc42 these are the current settings:


M569 P121.0
Driver 121.0 runs forwards, active low enable, mode spreadCycle, ccr 0x00053, toff 3, tblank 0, hstart/hend/hdec 5/0/0, pos 8

dc42

@arturolaz said in E3D Roto + Duet Roto Toolboard - Stepper motor stalling:

How can the CPU temperature can be calibrated?

Turn the printer off and give it time to reach ambient temperature. Read the ambient temperature from a thermometer. Turn the printer on and immediately use M122 to get a report from the board of interest. That report includes the CPU temperature. Compare it with ambient and calculate the correction required.

Currently, only the main board CPU temperature calibration can be stored, using the M912 command.

arturolaz

@dc42 the Duet3 control board is not installed inside the closed chamber as the roto toolboard is. How can this calibration affect the outcome of the printing tests?

Is there anything off in the M69 P121.0 report?

arturolaz

For anyone following.

I just measured the coils resistance in "hope" for them to be out of spec but they are not. Both measured 7.6 ohms at room temperature.

I haven't been able to print ABS nor PLA. I will keep trying tweaking the configuration but I feel that I have tried everything.