Heater 1 Fault (Stuck at 2000C)

  • I've been printing for a bit over 6mo with zero problems using a CR-10S4 with an E3D Volcano, 24V power, and a PT100 for my temp sensor on the hotend. I had this all working perfectly and two days ago the Duet2Wifi web interface started showing 2000C for the hotend temperature. I figured the PT100 might have issues, or maybe the cable is bad. I re-wired it, no luck. I changed the PT100 for the stock thermistor that ships with the E3D (connected in temp sensor port E1), reconfigured for the thermistor, and still showing 2000C. Not sure what the problem is.

    Here's the relevant bits of config:

    ; Heaters
    M307 H0 B0 S1.00                                   ; Disable bang-bang mode for the bed heater and set PWM limit
    M305 P0 T100000 B4138 C0 R4700                     ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120                                       ; Set temperature limit for heater 0 to 120C
    ;M305 P1 X200 R395                     		   ; Set PT100 + ADC parameters for heater 1 (BROKE?, USING THERMISTER BELOW)
    M305 P1 T100000 B4388 R4700                        ; Set thermistor + ADC parameters for heater 1
    M143 H1 S280                                       ; Set temperature limit for heater 1 to 280C
    ; Tools
    M563 P0 D0 H1 F1:2                                 ; Define tool 0 - use extruder 0, heater 1, fan 1, and fan 2
    G10 P0 X0 Y0 Z0                                    ; Set tool 0 axis offsets
    G10 P0 R0 S0                                       ; Set initial tool 0 active and standby temperatures to 0C

    Not sure what I am doing wrong 😞 Is there something I am missing? What could be causing this?


  • Also tried thermistor 7 on the expansion header since it was easy to connect across VSSA/THERMISTOR7, but I am getting ~3200C there.

  • I think P1 in M305 is channel for first extruder, witch is E0, not E1. So you should connect stock termistor to E0 temp sensor port and then it should work ok, assuming termistor and wires are ok.

  • administrators

    For some time we have been supplying 100 ohm resistors with the PT100 daughter boards. So if you have one, disconnect the PT100 cables from the daughter board and connect the resistor to the inner 2 of the 4 terminals instead. If you were using a 4-wire PT100 cable then you need to install the 2 jumpers too. With the resistor connected, you should get a reading very close to 0C. If you do, that confirms that the fault is in your PT100 sensor or the cable. If it still reads 2000C then the fault is in the configuration (M305 command in config.g) or the daughter board itself.

  • @dc42 Thanks for the quick response! I'll try find a 100ohm resistor somewhere in my mess soon! For now, I completely removed the PT100 daughterboard and I am trying to use a simple thermistor. I manually tested the thermistors resistance and response to the change of temp and it looks great. I connected the thermistor to the E1 male pins on the center of the board. I updated my config as shown in my original post, but I am still getting 2000C. I also cleared out the config-override.g file and checked all the other *.g files to make sure none of them are overwriting my heater configuration. Just in case, I sent the heater config command after boot with no change.

    I am not sure why I am still seeing 2000C regardless of what I do. I am expecting this simple thermistor to work. Once I get my thermistor working then I'll take a look at the PT100 config again.


  • @aidar said in Heater 1 Fault (Stuck at 2000C):


    Oops. This is the reason my thermistor was not working! I got confused. I assumed that the bed thermister was using ADC channel 0 which I also assumed was E0 on the board... but I did not realize that the bed thermistor is THERMISTOR0(ADC Channel 0), and E0 is THERMISTOR1 (ADC Channel 1). I had them off by 1.

    It's working now. Next step is to follow @dc42 instructions to debug the PT100 sensor to confirm it's the sensor and not the board/config.

    Thanks everyone!

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