Heater temp is off, way off.



  • I upgraded from the stock ender 3 board after the magic smoke was let out of the mosfet used for the bed heater.

    I used the online reprap configurator to build my config.g

    I have run auto tune and added the live to my config.g with the values from the M307 after.

    I have even swapped my thermistor for a brand new one.

    When I print, I have to set my temp way over what is recommended. Im talking 270 for pet-g and 320 for abs. Now, I used to be able to print at the specified temps with the duet 2 wifi. My hotend config is:
    M305 P1 T100000 B3950 C0 R4700
    M307 H0 A549.1 C154.8 D6.8 B0

    Any help is appreciated.



  • Where did you get those values? I dont remember what each parameter is for but here is mine, Stock duplicator 6 bed and an E3D Chimera, all 24v. Hope it helps.

    ; Heaters
    ; H0 bed 0
    M570 H0 P10 T10 ; set heater 0 fault detection H=heater P=time in seconds T=temperature excursion from setpoint
    M143 H0 S100 ; set heater 0 maximum heater temperature to 100C
    M305 P0 T100000 B4725 C0 R4700 ; set heater 0 thermistor + ADC parameters
    M307 H0 A119.8 C600.0 D0.3 S1.00 V24.0 B0 ; set heater 0 PID Heater 0 model:
    M912 P0 SO ; set heater 0 electronics temperature monitor adjustment in degC
    ; H1 extruder 0
    M570 H1 P5 T10 ; set heater 1 fault detection H=heater P=time in seconds T=temperature excursion from setpoint
    M143 H1 S280 ; set heater 1 maximum heater temperature to 280C
    M305 P1 T100000 B4725 C7.06e-8 ; set heater 1 thermistor + ADC parameters
    M307 H1 A791.4 C179.7 D5.2 S0.50 V24.1 B0 ; E3D Chimera set heater 1 PID heater
    M912 P1 SO ; set heater 1 electronics temperature monitor adjustment in degC
    ; H2 extruder 1
    M570 H2 P5 T10 ; set heater 2 fault detection H=heater P=time in seconds T=temperature excursion from setpoint
    M143 H2 S280 ; set heater 2 maximum heater temperature to 280C
    M305 P2 T100000 B4725 C7.06e-8 ; set heater 2 thermistor + ADC parameters
    M307 H2 A682.3 C166.3 D7.0 S0.50 V24.1 B0 ; E3D Chimera set heater 2 PID heater
    M912 P2 SO ; set heater 2 electronics temperature monitor adjustment in degC



  • Hi

    Your M305 is for heater1 , that is hotend, but M307 is for heater 0, that is bed heater, so you have tuned your bed, not hotend.



  • @aidar I was under the impression that M307 is what should be used to config the values recorded after running M303 H1 and recording the values.



  • Thats right, but see you config again, you apply these values to H0, not to H1.

    From your first post :
    M305 P1 T100000 B3950 C0 R4700
    M307 H0 A549.1 C154.8 D6.8 B0



  • @tompoper said in Heater temp is off, way off.:

    @aidar I was under the impression that M307 is what should be used to config the values recorded after running M303 H1 and recording the values.

    It is. But what you've posted is M307 H0 A549.1 C154.8 D6.8 B0. Note the "H0" - this should be H1.

    Or to put it another way, you've tuned heater1 with M303 then put those values into config.g for heater 0.

    Edit - was typing at the same time as @aidar



  • @aidar Lol, I see what you are referring to. I checked, this is a typo in transposing the config line to the web. It does apply to H1 in my config.g.



  • @tompoper The next thing to check is if you have a config-overide.g file and if so, does that have any values in it that differ from what you have in config.g.



  • I have an ender 3 running a Duet Wifi.

    below is my WORKING heater/thermistor settings.

    ; Heaters
    M305 P0 T100000 B3800 C0 R4850 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4725 C7.060000e-8 R4350 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S290 ; Set temperature limit for heater 1 to 290C


  • administrators

    @calvinx said in Heater temp is off, way off.:

    I have an ender 3 running a Duet Wifi.

    below is my WORKING heater/thermistor settings.

    ; Heaters
    M305 P0 T100000 B3800 C0 R4850 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4725 C7.060000e-8 R4350 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S290 ; Set temperature limit for heater 1 to 290C

    Why are you using R4850 and R4350 instead of R4700 (the correct value for a Duet WiFi/Ethernet)? If it's to try to get a more accurate reading at room temperature, you should be aware that changing the R value will probably make is a lot less accurate at printing temperatures - unless the Ender 3 thermistors have a very wide R25 tolerance and a narrow beta value tolerance.



  • @dc42

    I tried using the originals as is accepted in the docs and the temps would fluctuate wildly, those values stabilized everything and the web interface temps match what my external tests using my fluke thermocoupler gets.

    It works for me, and prints fine but if its not suitable for others, don't use it.



  • @tompoper said in Heater temp is off, way off.:

    3950

    the generic B3950 +/- 1% thermistors are somewhat problematic.
    the B3950 refers to the range of 25 to 50. They behave quite differently at temperatures around 200.
    i had the same problem and i just replaced it with a pt1000 and its been very accurate.

    If you actually calculate the values for a B3950 from the datasheet (if you are lucky that you get one)
    like https://www.tinytronics.nl/shop/index.php?route=product/attachmanager/getfile&product_attach_file_id=552
    and use the 220C value you will actually get a Beta value of 4171.
    And if you put in 25C, 50C and 220C you get β: 4666 K C : 1.072208e-7



  • @calvinx thanks for the info. Ill try all but the R value, as I understand it thats the resistance value for the board, if not please let me know.



  • @veti I think an upgrade is in order to my thermistor. The ender 3 was a good starting printer, but my eyes have been opened as to why a more expensive printer is worth the money.




 

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