@droftarts Yes I am using the duet 3 mini 5+ and using the latest beta firmware (Firmware: RepRapFirmware for Duet 3 Mini 5+ 3.3beta3 (2021-04-22))
M115
FIRMWARE_NAME: RepRapFirmware for Duet 3 Mini 5+ FIRMWARE_VERSION: 3.3beta3 ELECTRONICS: Duet 3 Mini5plus WiFi FIRMWARE_DATE: 2021-04-22 13:48:47
About 10-15% of the times, when I home I get these errors and then the corresponding motor just starts to shudder when moving. The rest of the times, it works perfectly. And this seems to happen only at the time of homing. If the homing succeeds, the rest of the print works fine without this issue popping.
So I am gonna guess something this wrong with my config/homing but unable to figure out what.
I have 3 different stepper motors
With the stock stepper , these issues don't happen. The error pops only with the LDO steppers.
The stepper current seems to play a role as well.
For the 1A stepper, If i set the current at 1A , the error crops up every time at homing. If I dial it down to 900mA, the error shows up roughly 50% of the time and at 800mA the error doesn't show up but prints end up having layer shift. One thing I noticed with this stepper is , it seems to have some resonant noise when moving.
The 1.68 A stepper follows the same pattern with the error cropping up at proportionately higher current (like around 1.2A+) . I have double checked the wiring (the harness that it came with had the correct ordering, so pretty sure it is not the wiring). THis stepper does not have the resonant noise when moving and is almost as quiet as the stock ender 3 stepper.
config.h
; Configuration file for Duet 3 Mini 5+ (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.2.3 on Wed Mar 17 2021 00:19:21 GMT-0700 (Pacific Daylight Time)
; General preferences
G90 ; send absolute coordinates...
M83 ; ...but relative extruder moves
M550 P"Prender" ; set printer name
M918 P1 E4 F2000000 ; configure direct-connect display
; Network
M552 S1 ; enable network
M586 P0 S1 ; enable HTTP
M586 P1 S0 ; disable FTP
M586 P2 S0 ; disable Telnet
; Drives
M569 P0.0 S1 ; physical drive 0.0 goes backwards
M569 P0.1 S1 ; physical drive 0.1 goes forwards
M569 P0.2 S1 ; physical drive 0.2 goes forwards
M569 P0.3 S1 ; physical drive 0.3 goes forwards
M584 X0.0 Y0.1 Z0.2 E0.3 ; set drive mapping
M350 X16 Y16 Z16 E16 I1 ; configure microstepping with interpolation
M92 X80.00 Y200.00 Z400.00 E823.53 ; set steps per mm
M566 X480.00 Y480.00 Z80.00 E270.00 P1 ; set maximum instantaneous speed changes (mm/min)
M203 X9000.00 Y9000.00 Z900.00 E3600.00 ; set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z100.00 E500.00 ; Set accelerations (mm/s^2)
M906 X1000 Y1250 Z850 E1000 I10 ; set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout
; Axis Limits
M208 X-40 Y-24 Z-1 S1 ; set axis minima
M208 X215 Y220 Z180 S0 ; set axis maxima
M564 H0 ; allow unhomed movement
; Endstops
M569 P0 D3 V100 ; Stealthchop X axis
M569 P1 D3 V100 ; Stealthchop Y Axis
M574 X1 Y1 S3 ; configure sensorless endstop for low end on X (Sensorless)
M574 Z1 S2 ; configure Z-probe endstop for low end on Z
; Z-Probe
M950 S0 C"io3.out" ; create servo pin 0 for BLTouch
M558 P9 C"^io3.in" H5 F120 T6000 ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X2 Y17 Z1.430 ; set Z probe trigger value, offset and trigger height
M557 X5:215 Y10:195 P5 ; define mesh grid
M376 H10 ; Fade height 10mm
; Heaters
M308 S0 P"temp0" Y"thermistor" T100000 B4092 ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out0" T0 ; create bed heater output on out0 and map it to sensor 0
M307 H0 R0.325 C144.7 D3.66 S1.00 V23.8 ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0 ; map heated bed to heater 0
M143 H0 S150 ; set temperature limit for heater 0 to 150C
M308 S1 P"temp1" Y"thermistor" T100000 B4092 ; configure sensor 1 as thermistor on pin temp1
M950 H1 C"out1" T1 ; create nozzle heater output on out1 and map it to sensor 1
M307 H1 R3.011 C121.1 D4.92 S1.00 V24.2 ; disable bang-bang mode for heater and set PWM limit
M143 H1 S275 ; set temperature limit for heater 1 to 275C
; Fans
M950 F0 C"out5" Q500 ; create fan 0 on pin out5 and set its frequency
M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"out6" Q500 ; create fan 1 on pin out6 and set its frequency
M106 P1 S1 H1 T45 ; set fan 1 value. Thermostatic control is turned on
M950 F2 C"out3" Q500 ; create fan 2 on pin out3 and set its frequency (case fan)
M106 P2 S1 H1 T45 ; set fan 2 value. Thermostatic control is turned on
; Tools
M563 P0 D0 H1 F0 ; define tool 0
G10 P0 X0 Y0 Z0 ; set tool 0 axis offsets
G10 P0 R0 S0 ; set initial tool 0 active and standby temperatures to 0C
; Custom settings are not defined
; Miscellaneous
M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; set voltage thresholds and actions to run on power loss
homex.g
M98 P"retractprobe.g"
M400 ; Wait for current moves to finish
M915 X S-1 F0 H200 R0 ; Sensitivity -3, don’t take action, don’t filter, 400steps/sec
M569 P0.0 V100 D3 ; reduce V parameter so driver operates in stealthChop
G4 P200 ; wait 200ms
; tuning
G91 ; set relative
M17 X ; Enable X motor
G1 H1 X0.5 F10000 ; Energize motors
G4 P200 ; Wait for 200ms
G1 H1 X10 F1000 ; Move away a bit
M913 X50 ; drop motor currents to 50%
G4 P200 ; Wait for 200ms
M400 ; Wait for move to finish
; Begin homing
G1 H1 X-255 F5000 ; move quickly to X axis endstop and stop there (first pass)
G1 H1 X10 F1000 ; Move away a bit with low accelaration
G1 H1 X-255 F5000 ; move quickly to X axis endstop and stop there (second pass)
; Reset everyting back to normal
G90 ; back to absolute positioning
M913 X100 ; motor currents back to 100%
M915 S127 X F0 H200 R0 ; Disable Logging and lower stall detection
M569 P0 V100 D3 ; Restore V parameter for motor
homey.g
M98 P"retractprobe.g"
M400 ; Wait for current moves to finish
M915 Y S1 R0 F0 H400 ; Sensitivity -3, don’t take action, don’t filter, 400steps/sec
M569 P0.1 V50 D3 ; reduce V parameter so driver operates in stealthChop
G4 P200 ; wait 200ms
; tuning
G91 ; set relative
M17 Y ; Enable Y motor
G1 H1 Y0.5 F10000 ; Energize motors
G4 P200 ; Wait for 200ms
G1 H1 Y10 F1000 ; Move away a bit
M913 Y70 ; drop motor currents to 70%
G4 P200 ; Wait for 200ms
M400 ; Wait for move to finish
; Begin homing
G1 H1 Y-255 F3000 ; move quickly to X axis endstop and stop there (first pass)
G1 H1 Y10 F1000 ; Move away a bit with low accelaration
G1 H1 Y-255 F3000 ; move quickly to X axis endstop and stop there (second pass)
; Reset everyting back to normal
G90 ; back to absolute positioning
M913 Y100 ; motor currents back to 100%
M915 S127 Y R0 F0 H200 ; Disable Logging and lower stall detection
M569 P1 V100 D3 ; Print in stealthchop
homez.g
; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.2.3 on Wed Mar 17 2021 00:19:21 GMT-0700 (Pacific Daylight Time)
G91 ; relative positioning
G1 H2 Z25 F6000 ; lift Z relative to current position
G90 ; absolute positioning
; First pass highspeed probing
M558 F400 ; Set high speed for first pass probing
G1 X115.5 Y100.5 F6000 ; go to first probe point
G30 ; home Z by probing the bed first pass
; Second pass highspeed probing
M558 F120 ; Set high speed for first pass probing
G1 X115.5 Y100.5 Z10 F6000 ; go to first probe point
G30 ; home Z by probing the bed first pass
homeall.g
M98 P"homex.g"
M98 P"homey.g"
M98 P"homez.g"
Does anyone know how I can fix the short to ground error for LDO stepper?
@jujojujo_2003 said in Sensorless homing not working:
Error short-to-ground reported by driver(s) 1
SO I was able to fix this by reducing the current. My stepper current was set to 900ma . Probably this was too high(even though this is < the rated current of both stepper and driver)
Lowering it to 700ma fixed the issue.
M98 P"retractprobe.g"
M400 ; Wait for current moves to finish
M913 X70 ; drop motor currents to 50%
M915 X S-3 R0 F0 H400 ; Sensitivity -3, don’t take action, don’t filter, 400steps/sec
M569 P0.0 V10 ; reduce V parameter so driver operates in stealthChop
G4 P200 ; wait 200ms
G91 ; set relative
G1 H1 X-255 F4000 ; move quickly to X axis endstop and stop there (first pass)
G90 ; back to absolute positioning
M913 X100 Y100 ; motor currents back to 100%
M915 S63 X Y R0 ; Disable Logging and lower stall detection
So this is the config that worked for me(On v3.3 beta). It looks like we need to dial M569's V param first such that for that V param, M915 S-63 always triggers a stall and M915 S63 always triggered a crash. Then you binary search on the correct S value
The problem now is that it homing doesn't work when the gantry is towards the end of x axis. But then If I home twice then it works. This seems very hacky. and also I keep getting "Error short-to-ground reported by driver(s) 1"
Looking at https://forum.duet3d.com/topic/21108/stall-detection-on-duet-3-mini/4 , I tried updating to V3.3 beta firmware and tried a bunch of S values for M915 from -128 to +127 but still the same crash.
@david-green Tried this one too but it crashes again. 
I have an ender 3 with these stepper motor drivers for X & Y axis https://www.printedsolid.com/products/ldo-nema-17-motor-high-temp-voron-ldo-42sth40-1004mahvrn
(this is a 0.9 stepper) and I am not able to get sensorless homing to work. I have a duet 3 mini 5+ board (with 3.2.2 firmware)
What I gather from https://duet3d.dozuki.com/Wiki/Stall_detection_and_sensorless_homing
there are the following variables that I can play with to get sensorless homing to work
i) The current percentage value for stepper motor in M913 command
ii) The feedrate for G1 command for homing
iii) The sensitivity params (S ) in M915
iv) Stealthchop <-> Spreadcycle cutoff given by V param in M569
From the docs, the only restriction is that feedrate must be lower than Stealthchop <-> Spreadcycle cutoff (which we get from M569 P0.0 command multipled by 60 to convert mm/s to mm/min)
I have tried a bunch of values for these 4 params
i) M913 ranging from 10-100
ii) Feedrate ranging from 2400 to 7500 (capped by stealthchop cutoff)
iii) Sensitivity ranging from -63 to +63
iv) V param for M569 ranging from 1 to 100
For all these cases, the X carriage just seems to move and crash with "Homing failed" message. Given that for all values, high and low I get the same crash, I am not sure how to move or change the parameters.
Also with V < 50, I either get "driver short to ground" error or "high motor temperature" error.
Shouldn't setting sensitivity (S param in M915) to a very low value cause the stall detect to be triggered all the time?
Any idea how I can get this to work?
config.g
homex.g
homey.g
retractprobe.g
homex.g
M98 P"retractprobe.g"
M913 X70 Y70 ; drop motor currents to 40%
M915 X S-20 R0 F0 H400; Sensitivity 4, don’t take action, don’t filter, 400steps/sec
G91 ; set relative
;G1 H2 Z5 F1200 ; lift z by 5
G1 H1 X-250 F4500 ; move left 250mm, stopping at the endstop
G90 ; back to absolute positioning
M913 X100 Y100 ; motor currents back to 100%
M915 S63 X Y R0 ; Disable Logging and lower stall detection