PT1000 config issue



  • Hi all!
    I'm upgrading my Duet Maestro CR-10S to a PT1000 I got from M3D and having a bit of an odd problem.

    I've been running fine with the standard thermistors, but want to do some high temp stuff. The Maestro is setup to do a PT1000 so I went that route rather than the PT100.

    When I configure the PT1000 I get weird readings. I imagine I'm missing something here.

    As I understand it the M305 should lose the thermistor settings for T, B and C and replace them with X500 for the PT1000. My hotend is on E0 (E1 is used as U axis for my second Z stepper).

    I've tried both X500 and X501 but both setups give me a reading of 279°C for extruder and 2000°C for the bed! When I check the PT1000 with a DVM it reads 1094 ohms.

    This is my original heaters section:

    ; Heaters
    M307 H0 B0 S1.00 ; Disable bang-bang mode for the bed heater and set PWM limit
    M305 P0 T100000 B4388 C7.060000e-8 R2200 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4388 C7.060000e-8 R2200 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S305 ; Set temperature limit for heater 1 to 305C

    And here's what I changed it to:

    ; Heaters
    M307 H0 B0 S1.00 ; Disable bang-bang mode for the bed heater and set PWM limit
    M305 P0 X500 R2200 ; Set PT1000 for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4388 C7.060000e-8 R2200 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S305 ; Set temperature limit for heater 1 to 305C

    What am I doing wrong here?



  • From your discription i understand, that you use your PT1000 on hotend. And its connected to E0 temp. But in your config its configured as bed sensor (P0). First hotend heater/sensor (E0) is P1 in M305 command, not P0.


  • administrators

    The correct commands are:

    M305 P0 X500 ; bed PT1000
    M305 P1 X501 ; first hot end PT1000

    You don't need the R2200 but it shouldn't matter if you have it.

    If you get a reading of 2000 then an error has occurred. To find out what error, send M305 P0, or M305 P1.

    If you are not using a PT1000 to measure the bed temperature, leave the M305 P0 line as it was before.



  • So the BED is P0 !! Duh. Knew it was something stupid I was missing ... Got confused by the hotend being E0, so I thought P0 ...

    Thanks guys! You guys rock! Off to do a PID tune ... 😀


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