Erratic behavior, skipped steps
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I take it all back. This is really strange and I don't think it has anything to do with the stepper, wiring, or belt. I think the stepper was skipping originally, and when I soldered the connector pins it was resolved.
The most recent print was going fine, and then it started to jitter like crazy just like in my video.
This time, I hotswapped the x and y axis. After pausing the print during the jitter, I connected X stepper and connected it to the Y, and connected the Y stepper to the X. My thinking was that if it was a problem with the Y stepper motor, the problem should continue on the Y axis. It didn't, instead it transferred over to the X axis.
I demonstrated the problem in this video. It is repeatable, but I don't know what is causing the symptom.
Is there something I'm missing in how I configured fhe firmware?
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@dwarren5684 That video is compelling evidence that there may be fault with the driver chip. Now it's not up to me because I'm just and end user like you, but unfortunately you've admitted that you hot swapped the wiring without first turning off power. The documentation clearly states that such an action could damage the driver chip. Which means that you might now struggle to get the board replaced under warranty.
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@deckingman You're absolutely right, it was a risk. The driver operates normally initially, but then things start to fall apart.
Next step is to try starting with the motors swapped to see if that driver continues to fail. If it does, I have two leadscrews for the z, and I could wire them in tandem to free up a driver. If I reach my limit, it's ok. My ancient printrbot could stand to be upgraded, and I'll happily buy a new duet board.
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Swapping the X and Y from the beginning created the same behavior, but on the X axis this time. That must mean it's either the driver, or something in the slicer.
I'll run the two Z motors in parallel, and use the free driver for the Y. I'm pretty confident that will clear up the error, so we'll see!
I wonder if anyone else has had a driver fail, it would be interesting to see if this is the same behavior.
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@dwarren5684 If it starts off fine, but then gets worse, I'd be looking for a heat-related break in the soldering, probably one of the solder legs of the driver chip. As it's an old board, it may have been through numerous heat cycles flexing the PCB. I'd go around the driver with a soldering iron, gently remelting the solder on each pin.
Either that or it is a failing driver
.Ian
TronXY X5S with Duet 3 MB6HC and Roto toolboard : Cartesian bed-slinger with Duet 3 Mini 5+ WiFi and 1LC : RRP Fisher Delta v1 with Duet 2 Maestro : Polargraph with Duet 2 WiFi
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A low cost stepper motor analyzer like this one can help diagnose current issues (bad connections, bad drivers, etc). https://forum.duet3d.com/topic/21312/low-cost-public-domain-stepper-analyzer-season-2?_=1614125424500
The reference design is in the public domain, waiting for the right entrepreneur.
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@droftarts Thanks, I'll give it a try! I hadn't considered that. It is strange that the axis works fine for about 30 minutes, and then it starts to fail. Your idea of a faulty solder joint is a good one. I'm out of flux, so I'll need to put that off for later. First I'll test out how the system works with another driver.
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@droftarts said in Erratic behavior, skipped steps:
@dwarren5684 If it starts off fine, but then gets worse, I'd be looking for a heat-related break in the soldering, probably one of the solder legs of the driver chip. As it's an old board, it may have been through numerous heat cycles flexing the PCB. I'd go around the driver with a soldering iron, gently remelting the solder on each pin.
Either that or it is a failing driver
.Ian
Also check the soldering of the motor output connectors on the Duet. I once came across a Duet with a bad soldered joint on one of the pins.
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I waited for the parallel connector adapter to wire them in parallel, then when I was reading the documentation I saw that there are two z connections in serial! Turns out I didn't need to order anything!
I connected the Y to E1 and the Zs to the serial connectors. So far it's looking great. None of the jitter or missed steps that I was getting from before. I'm going to file this under the "if it isn't broken, don't fix it", but if I lose another driver I'll check the solder joints.
One new issue that has cropped up is a long lag time between booting the duet and the motors becoming "engaged". Most of the time I try and home and the console says that the motors' phases aren't responding. Normally if I wait a while (10s) the motors will start working, but occasionally I need to restart and wait longer. Any ideas on that?
Thanks all for your help! I don't think I could have troubleshooted to this point without the advice.
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@dwarren5684 said in Erratic behavior, skipped steps:
Normally if I wait a while (10s) the motors will start working
Boot up can take a few seconds. 10 seconds from power on isn't unusual I think.
