motor phase disconnected on extruder driver

User3D

I keep getting "motor phase A/B disconnected on drivers 4/5" warnings on extruders' drivers. So I decided to upgrade from 3.3beta2 to 3.3 and I upgraded to RRF 3.3 but I still receive the warning. Wiring seems alright to me as part gets printed nicely. I've tapped drivers 0 and 1 to drive axes X - Y. I have Duet3 MB6HC . Warnings come irrespective of print speed.

dc42

@user3d can you tell whether the warnings come during normal printing, or during retract and reprime moves?

What extruder motors are they (linkto datasheet of possible please), what is the extruder steps/mm, and what current have you set for them in M906?

User3D

@dc42 said in motor phase disconnected on extruder drivers:

@user3d can you tell whether the warnings come during normal printing, or during retract and reprime moves?

During normal printing

What extruder motors are they (linkto datasheet of possible please), what is the extruder steps/mm, and what current have you set for them in M906?

EXTRUDER : BMG-X2 Extruder For Mosquito
MOTORS : NEMA17 Pancake Stepper Motor 25mm
STEPS/MM : 415
CURRENT : 800

dc42

@user3d you haven't given a motor part number, so I can't look up the specifications for it. However, I suspect that 800mA may be too much current for it, and that there is insufficient VIN voltage for the drivers to force 800mA current through it. That will give rise to those warnings.

So please report the model number of that motor. There is probably a label on the motor. If not, then at least measure the resistance of each phase using a multimeter, and report the values you measure.

User3D

@dc42 I changed current to 700mA ,but it didn't solve the issue.
Extruder motor : Nema 17 Panecake(https://www.bondtech.se/product/nema17-pancake-stepper-25mm/ - datasheet can be found here)
Also link to datasheet:
https://www.bondtech.se/wp-content/uploads/2019/02/13003-Nema17-25mm.pdf

Warnings come on the drivers where extruders are connected. So drivers are working fine I confirm.

dc42

@user3d thanks. What VIN voltage are you using? 700mA is right at the limit for those motors, however I would not expect that problem at 700mA if you are using 24V.

At 700mA those motors will run hot. I suggest 500 to 600mA.

User3D

@dc42 said in motor phase disconnected on extruder drivers:

@user3d thanks. What VIN voltage are you using?

24V

At 700mA those motors will run hot. I suggest 500 to 600mA.

It didn't work! I still get the warnings.

dc42

@user3d are the extruders working properly?

With power off, please disconnect one of those motors from the Duet and use a multimeter to measure the resistance of one of the phases, so that we can see whether it matches the datasheet.

User3D

@dc42 Measured Phase resistance of motor = 4.8 ohm

Phaedrux

So just to confirm, you have identified the correct phase pairs?

https://duet3d.dozuki.com/Wiki/Choosing_and_connecting_stepper_motors#Section_Identifying_the_stepper_motor_phases

And you're still getting the phase warnings on those drivers?

Can you test those drivers with a different motor and see if it's the same? We need to verify if it's a problem with the motor or the driver.

User3D

@phaedrux Back when I started receiving warnings, my extruder was connected on driver 4 and Z was on 3. So I swapped the connections and now I receive warnings on driver 3 where extruder motor is connected right now. This confirms, there is no issue with drivers. Also I've dual extruder and I've observed that warnings come for extruder on work. So I believe motor is not an issue here either.
so to summarize:
1) error is always on the active extruder (the one thats printing)
2) its always on the driver where I connect the extruder. if I switch from driver 2 to 3, the error passes on to driver 3.
3) Phases of motors verified as suggested by Phaedrux and are correct.
4) The error frequency is not always same. Sometimes it appears every 10s while printing, sometimes 1 in 30 mins ..sometimes only few warnings appear during entire print.

Any suggestions to find the root cause here? @Phaedrux @dc42

Thank you.

Phaedrux

Most unusual...

Can you please share your config.g and the results of sending M122 and M98 P"config.g" in the gcode console?

When you say it follows the extruder motor and not the driver, that makes me think it's the motor wiring either external or internal to the motor itself, however, you also say it happens with both extruder motors depending on which is being used at the time.

Can you share some photos of the extruders and the wiring? Maybe there's something odd going on.

Are you able to re-crimp the extruder motors connectors?