How to configure thermistor for bed?



  • As my Subject says, I'm stuck at what should be simple, but really isn't, for me.

    Please do not say go read the wiki.
    I have literally read it all 3-5 times.

    Anyway, back to situation at hand:

    Specifications
    I use thermocoupler daughterboard, which I bought along with the Duet WiFi.
    I use 1 thermocoupler for hotend and 1 thermistor for heatbed.

    Goal:
    Initial setup followed by PID tuning.

    [[language]]
    ; Tool definition - Standard E3Dv6
    M563 P0 D0 H1 ; Define tool 0 uses extruder drive E0 and heater 1
    
    G10 P0 X0 Y0 ; Set tool 1 axis offsets
    G10 P0 R0 S0 ; Set initial tool 1 active and standby temperatures to 0C
    
    

    How to specify which Thermistor to use for my bed? I simply just can't find that.. only a lot about how to set ADC, and then a note about not having to do so, since WiFi has it build in.

    I have plugged in my bed thermistor at second pins from the right, with usb at the right side.



  • The documentation here should answer the OPs questions https://duet3d.com/wiki/Connecting_thermistors


  • administrators

    The bed thermistor should be connected to the 2-pin connector provided for it, which is next to the bed heater output terminals. See the wiring diagram at https://duet3d.com/wiki/Duet_WiFi_wiring_diagrams.



  • Ohh, I totally missed the place to connect it.. that's why then… some of it... a shame my wires aren't long enough to reach hat part anymore 😞

    So, how do I tell firmware that I'm defining my bed and not my heater? I really could use a PIN out diagram. Meaning what I define using P305 P0,P1,P2 etc etc..

    I have been using this to try configuring my printer: https://duet3d.com/wiki/Configuring_RepRapFirmware_for_a_Cartesian_printer#Heater_and_thermistor_section

    Seems both heaters and bed are defined using M305 and P0 as far as the wiki says?
    How do the firmware know what is heater and heated bed?

    Ater wiring up my heater gives me error (worked before) and now bed is jumping between 24c and 2000c
    Guess it's because both are defined with P0, but I don't know what Pn the bed thermistor is. If I decided to use my other thermocoupler channel for my bed, how would I even start telling the firmware the temperature for bed is Thermocoupler channel 2?

    [[language]]
    ; Bed Temperature
    M305 P0 T100000 B3950 R4700 H0 L0 
    
    ; PID
    ; M301 H0 S1.00 P10 I0.1 D200 T0.4 W180 B30 ; Use PID on bed heater (may require further tuning)
    
    ; https://duet3d.com/wiki/Connecting_thermocouples
    M305 P0 X100 ; Heater 0 uses Thermocoupler on channel 100 (100-103)
    
    ; Tool definition - Standard E3Dv6
    M563 P0 D0 H1 ; Define tool 0 uses extruder drive E0 and heater 1
    
    


  • @deckingman:

    The documentation here should answer the OPs questions https://duet3d.com/wiki/Connecting_thermistors

    The problem is, that it really doesn't. It talks about ADC but not how to specify the gcode I need to activate/specify heated bed thermistor.



  • Figured it out.

    Heated bed is P0 while Heaters are P1++

    [[language]]
    ; Bed Temperature
    M305 P0 T100000 B3950 R4700 H0 L0 
    ; Tool definition - Standard E3Dv6
    M563 P0 D0 H1 ; Define tool 0 uses extruder drive E0 and heater 1
    
    

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