PT100 without PT100 board on Maestro



  • This is mostly for curiosity, but I've seen claims its possible to read off PT100 sensors by fudging the thermistor coefficients, or by pretending its a PT1000 sensor and fudging the given seriers resistance value.

    @dc42 said in Controlling a Cetus3D with Duet3D 0.8.5:

    @fotomas said in Controlling a Cetus3D with Duet3D 0.8.5:

    @cookie

    I'm using the original cetus thermistor. It works well after finding the correct values for it.

    I do not think a negative B value is common.
    M305 P1 R4700 T112 B-425 C7.060000e-8

    Looks like you are using a PT100 but you have connected it directly to the thermistor input. This will give you a very poor resolution and you should use the PT100 daughter board instead. However, if you want to use a direct connection then I suggest this:

    M305 P1 X501 R47000

    This says you are using a PT1000 sensor, but inflates the series resistor value by a factor of 10 to compensate for the fact that you are actually using a PT100.

    Adapting to Duet Maestro board I try to add a virtual ambient temp sensor:

    M305 P103 S"ambientX502" X502 R22000 ;doesnt work works wiht P103
    M305 P103 S"ambientX2" X2 R2200 T105 B-425 C7.060000E-8 ; doesnt work works wiht P103

    but if I map E1 thermistor to E0 it does work:

    M305 P1 X502 R22000 ;works
    M305 P1 X2 R2200 T105 B-425 C7.060000E-8 ;works

    edit: figured it out.


 

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