Solved Thermister problems: Duet Wifi Board v1.0

[T3P3Tony]

@wurth51 ok, well it's good that you have the VIN being detected.

What happens with the reading in the third input if you test the thermistors there?

What command are you using to set them up?

[wurth51]

@t3p3tony Hi. I assume you are referring to the config settings for the thermistors. If not please let me know what to do to get the info for you. Really appreciate your assist on this.
config.g**
Configuration file for Duet WiFi (firmware version 3.3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.3.3 on Sun Oct 03 2021 21:00:10 GMT-0700 (Pacific Daylight Time)

; General preferences
M575 P1 S1 B57600 ; enable support for PanelDue
G90 ; send absolute coordinates...
M83 ; ...but relative extruder moves
M550 P"Duett Valcano" ; set printer name

; Network
M551 P"xxxxxxxxxxxx" ; set password
M552 S1 ; enable network
M586 P0 S1 ; enable HTTP
M586 P1 S0 ; disable FTP
M586 P2 S0 ; disable Telnet

; Drives
M569 P0 S1 ; physical drive 0 goes forwards
M569 P1 S1 ; physical drive 1 goes forwards
M569 P2 S1 ; physical drive 2 goes forwards
M569 P3 S1 ; physical drive 3 goes forwards
M569 P4 S1 ; physical drive 4 goes forwards
M584 X0 Y1 Z2 E3:4 ; set drive mapping
M350 X16 Y16 Z16 E16:16 I1 ; configure microstepping with interpolation
M92 X64.50 Y64.50 Z754.00 E640.00:640.00 ; set steps per mm
M566 X900.00 Y900.00 Z60.00 E120.00:120.00 ; set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z180.00 E1200.00:1200.00 ; set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z20.00 E250.00:250.00 ; set accelerations (mm/s^2)
M906 X800 Y800 Z800 E800:800 I30 ; set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1 ; set axis minima
M208 X210 Y210 Z180 S0 ; set axis maxima

; Endstops
M574 X1 S1 P"xstop" ; configure active-high endstop for low end on X via pin xstop
M574 Y1 S1 P"ystop" ; configure active-high endstop for low end on Y via pin ystop
M574 Z1 S1 P"zstop" ; configure active-high endstop for low end on Z via pin zstop

; Z-Probe
M558 P0 H5 F120 T6000 ; disable Z probe but set dive height, probe speed and travel speed
M557 X15:190 Y15:195 S20 ; define mesh grid

; Heaters
M308 S0 P"bedtemp" Y"thermistor" T100000 B4092 ; configure sensor 0 as thermistor on pin bedtemp
M950 H0 C"bedheat" T0 ; create bed heater output on bedheat and map it to sensor 0
M307 H0 B0 R0.206 C505.8 D3.68 S1.00 V12.5 ; created for bed PID after running M303 Sept2021
;M307 H0 B0 S1.00 ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0 ; map heated bed to heater 0
M143 H0 S85 ; set temperature limit for heater 0 to 85C
M308 S1 P"e0temp" Y"thermistor" T100000 B4138 ; configure sensor 1 as thermistor on pin e0temp
M950 H1 C"e0heat" T1 ; create nozzle heater output on e0heat and map it to sensor 1
M307 H1 B0 R1.446 C274.7 D8.49 S1.00 V11.4 ; created based on M303 command Sept2021
;M307 H1 B0 S1.00 ; disable bang-bang mode for heater and set PWM limit
M143 H1 S280 ; set temperature limit for heater 1 to 280C

; Fans
M950 F0 C"fan0" Q500 ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"fan1" Q500 ; create fan 1 on pin fan1 and set its frequency
M106 P1 S1 H1 T45 ; set fan 1 value. Thermostatic control is turned on

; Tools
M563 P0 S"Right" 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
M563 P1 S"Left" D1 H1 F0 ; define tool 1
G10 P1 X0 Y0 Z0 ; set tool 1 axis offsets
G10 P1 R0 S0 ; set initial tool 1 active and standby temperatures to 0C

; Custom settings are not defined

[T3P3Tony]

@wurth51

M308 S0 P"bedtemp" Y"thermistor" T100000 B4092 ; configure sensor 0 as thermistor on pin bedtemp
....
M308 S1 P"e0temp" Y"thermistor" T100000 B4138 ; configure sensor 1 as thermistor on pin e0temp

Those look right. Please add the following line:

M308 S2 P"e1temp" Y"thermistor" T100000 B4138 ; configure sensor 1 as thermistor on pin e0temp

A new sensor should appear in the "extras" tab on DWC. Now try plugging each of the bed and e1 thermistors in there to see what readings you get.

Also try shorting (using a jumper) across the bedtemp and e0 temp inputs to see if the reading changes from -273 to 2000.

[wurth51]

@t3p3tony said in Thermister problems: Duet Wifi Board v1.0:

M308 S2 P"e1temp" Y"thermistor" T100000 B4138 ; configure sensor 1 as thermistor on pin e0temp

Ok.... that brought all three thermisters up on the interface. I shorted each one out and there was no change to the readings. Held constant at -273.1 deg. Looks like a component failure??? Is this repairable? Board is way out of warranty.

[dc42]

@wurth51 if they all read -273 then it sounds like the VSSA fuse has failed. https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#Section_VSSA_fuse

[wurth51]

@dc42

Thank you very much for responding to this post. It was in fact the fuse (took me awhile to find it). Did a quick bypass on the fuse and all the thermistors immediately started reading normal. I will with the article you provided to put a permanent solution in place.

Not sure how to mark this thread as "closed/solved"!

[wurth51]

@wurth51

A big thanks to T3P3Tony for their assistance in getting me past the software being the problem and to dc42 for pointing me to the hardware solution.

It's a great day to be a Duet user.

[T3P3Tony]

@wurth51 worth considering how the VSSA fuse was blown. It is a PTC fuse that should reset itself after time when it triggers so if it failed it may have been exposed, or repeatedly exposed, to a high enough current to cause it to fail. Its there to protect the VSSA input on the temperature headers from a high voltage which is sometimes caused when the hotend (or bed) heater wiring shorts to a temperature wiring. Worth checking your wiring! from your first post It sounds like you might have an issue with using a 12V heater at 24V as well which is not recommended.

[dc42]

@t3p3tony he has a v1.0 board so the fuse isn't a PTC self-resetting one. Nevertheless, there must have been a short or transient of some sort to cause it to blow.

[wurth51]

@dc42

Got the little resettable fuse and 10k resistor installed. Board is now working fine.

The article you referred me to indicated that the firmware would respond to a "short" based on the installation of the 10k resistor. Can you elaborate on what I would expect to see should the fuse blow?

Thanks

[dc42]

@wurth51 if you get a short between Vssa and a higher voltage then you should get a message on the DWC console warning you of the short.