Solved Solved - Again short-to-ground on replacement board - Duet 2 Wfi
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if you connect only one z motor this message does not appear?
just to rule out a bad motor. -
@Veti When I was busy troubleshooting I did switch both Z-motors for the X and Y axis (physically, on the frame and electrical) and the X and Y are now set as the Z-motors.
Still only X and Y work, and the Z not anymore, currently due to the error (?) no more holding torque either.
I have not yet tested if the error persists when I disconnect both Z-motors. Will do so this evening.
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@Tyoi said in Again short-to-ground on replacement board (Duet 2 Wifi):
currently due to the error (?) no more holding torque either.
check your wiring and phases. just because they are the same motor does not mean that the phases are the same.
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@Veti All motors have been tested, using multimeter and scope (especially after I received the replacement board to exclude such problems and not needlessly repeat a wiring error or similar).
Pairs are on the outer two pins on the connector: blk+grn, red+blu as also stated on the datasheet here and connected as mentioned in previously linked page: "Each stepper motor connector has four pins. You must connect the two wires for one phase of the stepper motor between the two pins at one end of the connector, and the wires for the other phase to the two pins at the other end." and using the Duet 2 wiring diagram here.
Will re-test this evening though, can't hurt to be sure-sure.
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Pairs are on the outer two pins on the connector: .... You must connect the two wires for one phase of the stepper motor between the two pins at one end of the connector,.
I'm confused by what you are saying here. You say that one pair are using the outer two pins but the duet documentation says the two left pins.
Lets take the black and green pairs as an example. Do you have them connected like pic 1 or pic 2 below?
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That's no problem. Actual order doesn't matter as they work plugged in either way round.
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Please check on the underside of your Duet that there are no solder bridges between pairs of pins of the Zb motor connector. Duets are tested with 2 jumpers in the Zb connector, so solder bridges there are not picked up during testing.
Also check that there is no chance of the back of the Duet shorting against anything below it; and if you have mounted the Duet on metal standoff pillars, that the pillar close to the Za motor connector isn't touching the adjacent Za connector solder joint on the underside of the Duet.
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@dc42 Hello dc42! I will check as soon as possible if any solder bridges exist as you mentioned.
I am very sure no shorting on the underside of the board is possible. The standoffs used are made of PETG (are part of the housing) and are 15mm high to provide ample ventilation. Also no metallic washers or such are used.
At the time of testing I actually only mounted the board with two screws, the top left one next to LED's indicating the heater status for the hotend(s) and voltages and on the bottom right at the expansion port. All screws used are smaller than the white circle on the PCB.
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You get this error if you connected the motor phases the wrong way. Either by wiring, or by shorting. Use a Multimeter to find a phase. Then connect the phases according to the wiring diagram. If the motor does not spin, it should be enough to swap the cable of ONE of the phases either left or right pair (not entirely sure).
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@dgrat said in Again short-to-ground on replacement board (Duet 2 Wifi):
You get this error if you connected the motor phases the wrong way. Either by wiring, or by shorting.
As @dgrat says. So please check that for each of the Z stepper motors, there is continuity between the 2 pins at once end of the 4-pin connector where it plugs into the Duet, and continuity between the 2 pins at the other end of the connector. Also check that there is no continuity between the 2 pins at one end and the 2 pins at the other end.
If the wires come directly out of the stepper motor with no connector, then the phase pairs are usually red-blue and green-black, but it's not impossible that a motor could have been manufactured incorrectly. If there is a 6-pin connector on the stepper motor itself, then the pinouts of those connectors vary between manufacturers, so you must always check which pairs of wires are the phases.
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@dgrat @dc42 Thank you for the suggestions, will try/test first thing as I come back home.
The motors do have a connector on them, I will re-test the pairs on them to double check incorrect internal wiring.
Am I correct in assuming the error short-to-ground prevents any further movement from the drive but does not mean the driver is broken?
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You can also test the motor:
- Phases should have continuity
- Shorting a phase must increase motor resistance when you want to spin it
If not, it's the motor. If yes, the wiring.
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@Tyoi
Yes. At least in my case. Usually, it is a help that tells you that the wiring is faulty. -
@Tyoi said in Again short-to-ground on replacement board (Duet 2 Wifi):
Am I correct in assuming the error short-to-ground prevents any further movement from the drive but does not mean the driver is broken?
The short to ground message can mean any of:
- Motor phases incorrectly wired
- Shorted mosfet in the driver chip
- A genuine wiring short to ground
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Gentlemen, -women,
Thank you for your help, I managed to resolve the situation. Indeed even though I had a batch of the same motors, with the same type no etc. there where internal wiring differences. For a few motors the pole pair wasn't on pin 1+2 or 3+4 but on 1+3 and 2+4. This was a learning moment for me seeing that in my experience using steppers I never had something like this happen to me. Perhaps these motors are a little bit too much 'china-y'.
What strikes me as weird though is that I have changed the motors on the board, testing the Z motors on the other steppers, which worked. So, not sure why.
Board is now working as intended, no more short-to-ground errors and sensorless homing seems to work a lot better on the X and Y axis now too.
Again thanks for the swift (correct) responses
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the chinese suppliers source the parts from various places where they can get cheap deals.
this mean that the motors might look the same, but are actually manufactured by different companies.any part you receive from chine should be checked before using (especially hotbend and heater catridges) fans etc..
some shady dealer will just relabel stuff if they run on of stock.