Thermocouple configure in RR3



  • My bed heater use a K type thermocouple that worked fine in RR2 but now I can't figure out what the port names to use for thermocouple input in RepRap 3 beta firmware, I'm using a Duet 2 Ethernet controller and my RR2 config was:
    M305 P0 X150 T"k"



  • So you'll need to change the M305 command to something like:

    M307 H0 A___ C___ D____ V____ B0 ; change the values after running a PID autotune

    M308 S0 P"spi.cs1" Y"thermocouple-max31856" K"c" ; Configure the bed temp sensor. This is the equivalent to your old one, assuming you're using the daughterboard on the duet and not on an expansion board.

    M143 H0 S120 ; limit the bed temp
    ..
    ..
    M950 H0 C"bedheat" T0 ; define the bed heater and bind the sensor we configured above to it.

    The M950 have to come after the sensor is first configured.


  • administrators

    @Nuramori said in Thermocouple configure in RR3:

    M308 S0 P"spi.cs1" Y"thermocouple-max31856" K"c"

    Correct except that for a K-type thermocouple it should end with K"k" not K"c". Also the M307 command should come after the M950 command.



  • @Nuramori said in Thermocouple configure in RR3:

    So you'll need to change the M305 command to something like:

    M307 H0 A___ C___ D____ V____ B0 ; change the values after running a PID autotune

    M308 S0 P"spi.cs1" Y"thermocouple-max31856" K"c" ; Configure the bed temp sensor. This is the equivalent to your old one, assuming you're using the daughterboard on the duet and not on an expansion board.

    M143 H0 S120 ; limit the bed temp
    ..
    ..
    M950 H0 C"bedheat" T0 ; define the bed heater and bind the sensor we configured above to it.

    The M950 have to come after the sensor is first configured.

    Thank you! That was the P value I was looking for 👍



  • @dc42 said in Thermocouple configure in RR3:

    @Nuramori said in Thermocouple configure in RR3:

    M308 S0 P"spi.cs1" Y"thermocouple-max31856" K"c"

    Correct except that for a K-type thermocouple it should end with K"k" not K"c". Also the M307 command should come after the M950 command.

    Good to know about the PID coming after! I'll change that in my config. What are the ramifications of it coming elsewhere?


  • administrators

    @Nuramori said in Thermocouple configure in RR3:

    Good to know about the PID coming after! I'll change that in my config. What are the ramifications of it coming elsewhere?

    I would need to check; but on Duet 3 I think it would not be actioned because the heater doesn't exist yet, and if using an attached RPi then an error message would be produced. Duet 2 has default heaters so it would probably work.


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