Multiple Heatbeds on SKR 1.4 w. rpi3



  • Has anyone got a RRF 3.1 config that is working with more than one heatbed?

    I'm trying to get one setup with 3 beds but I'm running into issues when adding the third bed.

    An extra sensor shows up in the temperature chart and under the extra tapb of tools + extras but I get several errors on boot.

    M950, M143 and M307 all say "parameter 'H' too high."
    And M140 says "parameter 'P' too high."

    In my research I've been lead to believe that it should support up to 4 beds.

    I'll attach the relevant code below.

    ; Heaters - Beds
    
    ; Bed 1
    
    M308 S0 P"bedtemp" A"Bed 1" Y"thermistor" T100000 B4138  ; configure sensor 0 as thermistor on pin bedtemp
    M950 H0 C"bed" T0								; create bed heater output on bed and map it to sensor 0
    M143 H0 S90										; bed temp limit
    M140 H0	P0										; map bed to heater 0
    M307 H0 B0 S1.00								; disable bang-bang mode for the bed heater and set PWM limit
    
    ; Bed 2
    
    M308 S2 P"e1temp" A"bed 2" Y"thermistor" T100000 B4138	; configure sensor 2 as thermistor on pin e1temp;
    M950 H2 C"e1heat" T2							; create bed heater output on e1heat and map it to sensor 2
    M143 H2 S90										; bed temp limit
    ;M140 H2 P2										; map bed to heater 2
    M307 H2 B0 S1.00								; disable bang-bang mode for the bed heater and set PWM limit
    
    ; Bed 3
    
    M308 S3 P"P0.26" A"Bed 3" Y"thermistor" T100000 B4138	; configure sensor 3 as thermistor on pin P0.26
    M950 H3 C"P3.26" T3								; create bed heater output on P3.26 and map it to sensor 3
    M143 H3 S90									; bed temp limit
    M140 H3 P3										; map bed to heater 3
    M307 H3 B0 S1.00								; disable bang-bang mode for the bed heater and set PWM limit
    

    Edit: I should probably note that I'm running it on an SKR v1.4 connected to a Raspberry pi 3. Now that I think about it, there very well could be a limitation with the firmware available for the SKR at the moment. Still it would be nice to figure out whats going on all the same.


  • Moderator

    Moved topic to the RRF on other controllers area.



  • The firmware is only configured for 3 heaters (since there is typically only 3 suitable MOSFETS on LPC based boards and we are pretty tight for memory). I assume you are using H1 somewhere else in your config?

    What is it you are building that needs 3 beds?



  • Oh and if you have further LPC specific questions you may get an answer more quickly using the discord server (see the LPC wiki for details).


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