Short to ground
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With two drivers I get the message "Short to ground". It can't be the plugs and cables because they work on the other drivers. Does this mean the drivers are broken and I need to buy a new board?
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If you've confirmed that the motors and wiring work on other drivers, then yes it seems likely the drivers themselves are damaged.
Whether you need a new board or not would depend on how many drivers you need and which board it is. Perhaps a smaller expansion board would suffice?
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@Phaedrux said in Short to ground:
Perhaps a smaller expansion board would suffice
The expansion board seems like a good idea, is there anything suitable for the Duet2 wifi... I can only find expansions for the Duet3?
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@Phaedrux Even though I haven't plugged a cable into driver 4, I get the message immediately after starting: "Driver 4 error: over temperature shutdown". What can I do about it?
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@axiom I have now ordered a Duet Expansion Breakout Board...does it even make sense to connect it when this message comes...within a week 3 drivers have now said goodbye (different motors)
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@axiom note that the Expansion Breakout Board doesn’t drive stepper motors directly, it just provides the -3.6V to +3.6V (or 5V) for external drivers.
As to why your drivers are failing, I expect one of your motors is faulty, or the wiring is making partial contact (wire break or poor crimp connection), and it’s killing the drivers. A poor connection causes higher resistance, so the stepper driver has to increase the voltage to achieve the target current. If the wire contact then breaks, or reconnects with lower resistance, the stepper driver is then over-volt and needs to sink the voltage. This generates a lot of heat in the driver, and eventual failure. It’s similar to connecting/disconnecting a motor when powered up, but more frequently; See point two here: https://docs.duet3d.com/en/User_manual/Troubleshooting/How_to_destroy_your_Duet#methods-that-might-work-or-only-impact-some-functions-of-your-duet
Check the resistance of each phase of each motor, for shorts across phases, and for any loose crimps or damaged wires. When there is a short between phases, the Duet uses all the drivers to sink the voltage/current until the affected driver has time to shut down (a few milliseconds usually). So it’s possible to damage or kill all the drivers with one short circuit, if the current is set particularly high, especially if all the motors are working at the same time; there’s less capacity to absorb the voltage spike. By then moving a faulty motor to the next driver, there is less buffer available for the next time the motor shorts out.
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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@droftarts Even if I unplug all drivers, the message comes: "Driver 4 error: over temperature shutdown". If I close the message, it doesn't come back until the next restart. I then tested all drivers individually: The two Z-axes work, and the y-axis.
I also tested all individual connections (termistor, fan, bed, etc.) and connectors. Can resetting the board help? If so...I didn't find the instructions in the documentation...or does that make no sense. Should I not connect the Duet Expansion Breakout Board (probably arriving on Tuesday) at all as long as the message "over temperature" comes up? -
@axiom the over temperature message is specific to that driver. Does it feel hot? You can get spurious messages if the SPI bus (used to communicate with drivers to set their configuration) is damaged, or a damaged driver is sending garbled message, but this seems pretty consistent that driver 4 (E2 on a Duet 2) is damaged. You can disable the driver and messages in config.g using
M569 P4 R-1Ian
