RRF 3 Fan with virtual heater control not working

  • Hello everyone

    I just tried to use the virtual heaters 100,101,102 to control a fan (no. 0) as follows:

    M950 F0 C"duex.fan3+duex.fan4"
    M106 P0 T45 H100:101:102

    Unfortunately I get the error "Sensor number out of range". Is there a new way on how to utilise the mcu temp and driver temp for fans?

  • Moderator

    Did you define H100, 101 and 102 with M308? The way virtual heaters works has changed with RRF3:

    This code replaces M305 in RepRapFirmware 3. In earlier versions of RepRapFirmware, sensors only existed in combination with heaters, which necessitated the concept of a "virtual heater" to represent a sensor with no associated heater (e.g. MCU temperature sensor). RepRapFirmware 3 allows sensors to be defined independently of heaters. The association between heaters and sensors is defined using M950.

    See the examples in M308 for guidance.


  • It might be nice if the M308 page actually told you that you can only have Sensors 0-31 defined. I converted my Duet Maestro config which used Virtual Heaters 100,101,102 to the RRF3 and took a little while to notice I couldn't setup sensor 100. Trial an error messages only let me go up to 31. It would be helpful if there was a note on the M308 GCode command.

    I'm including this here for the next guy who ends up with the same issue I had trying to create the Virtual Heater 100, 101, 102.

  • Moderator

    @PDBeal A note has been added to M308 regarding the limit of 32 sensors. Sorry you have to discover that through trial and error.

Log in to reply