[Solved] Short-to-ground on driver 3

pugzor · 18 Apr 2018, 22:07

Hi there,

I got my Duet Wifi late last year for my Hypercube Evolution and had a lot of success with it (seriously - very happy with the purchase). Anyway, I wanted to upgrade my hotend to a Titan Aero and unfortunately got caught in the bearinggate issue. Took a break while that was being sorted out, got an Ender-2, and have been mucking around with that until recently.

Recently I've come back to the Hypercube and tried to get it running again. Changed a few things (belt driven dual axis to standard dual Z motors) but also made my own bracket for the Aero since I couldn't find one anywhere that would accommodate for the 40mm stepper E3D recommended.

The problem now though is that everything seems to be working bar the extruder motor. It's a genuine E3D MT-1703HSM168RE. When I heat up the hotend to the required temperature and try to extrude 5mm at 1mm/s, I get the error that there's a short-to-ground on driver 3.

My main question is - does this error usually indicate there's an issue with the driver, assuming there's not a genuine short somewhere? Or can just wiring up the stepper indicate an issue?

The way I've currently got this motor wired is (pins are left to right on both the Duet and stepper):

Pin 1 on the stepper to Pin 1 (2B) on the Duet
Pin 2 on the stepper unused
Pin 3 on the stepper to Pin 2 (2A) on the Duet
Pin 4 on the stepper to Pin 4 (1B) on the Duet
Pin 5 on the stepper unused
Pin 6 on the stepper to Pin 3 (1A) on the Duet

Anyone able to give me a tip on this?

Thanks in advance.

Kezat · 18 Apr 2018, 22:12

Does unplugging the motor (power off board first) connector from the board clear the error? And make sure you don't have a bit of metal shorting out the underside of the board. If you cant clear the error by removing the connector a good visual inspection might be a good idea.

pugzor · 18 Apr 2018, 23:36

@kezat said in Short-to-ground on driver 3:

Does unplugging the motor (power off board first) connector from the board clear the error? And make sure you don't have a bit of metal shorting out the underside of the board. If you cant clear the error by removing the connector a good visual inspection might be a good idea.

Hey @Kezat, I've tried that a few times without success. Have had a good visual inspection too and can't seem anything unusual on the board. My board is elevated above the mounting surface by a good 8-10mm too and I've run some air over it to try and clear it. Compared resistance between pins on the Duet side and they all seem to be around 11.4m Ohms between each other (another set of pins was around 10.9m Ohms so I'm guessing that's kind of normal).

At a bit of a loss!

Kezat · 19 Apr 2018, 00:29

Just to be clear, you still get the short to ground error message on driver 3 when you try and command a move of driver 3 without anything connected to that board connector correct? I'm trying to determine if the board has a fault or the issue is the extruder motor/wiring (driver3?) that is at fault.

pugzor · 19 Apr 2018, 00:51

@kezat said in Short-to-ground on driver 3:

Just to be clear, you still get the short to ground error message on driver 3 when you try and command a move of driver 3 without anything connected to that board connector correct? I'm trying to determine if the board has a fault or the issue is the extruder motor/wiring (driver3?) that is at fault.

Sorry, hadn't tried this. When I remove the connector completely from the board and send a command to the E0 stepper (at temperature), nothing happens and no error comes up. That would indicate a wiring error between plug and E0 stepper, wouldn't it?

Kezat · 19 Apr 2018, 01:09

@pugzor Yup! So the issue is not be the board, that's good news. I'm not sure if the Duet will show this type of error if you have the motor wired wrong ie if you have a coil connected across the two coil outputs but i would guess not, mostly likely your extuder motor cable actually does have the wires shorted out together or to a grounded metal frame.

pugzor · 19 Apr 2018, 01:18

@kezat I went for gold and just switched around Pins 3 and 4 on the stepper side of things - it stopped the error and is extruding properly now. So ends up this error can come up if you've just wired a stepper incorrectly. All fixed!

Kezat · 19 Apr 2018, 01:26

@pugzor Yay, glad it was a easy fix.