Duet 3 V1.0-SSR to power 110v bed heater



  • I'm working on getting my Duet 3 setup with RRF 3.1.3 setup but I'm having issues getting my heatbed to power up. I'm using a 110v silicon mat with a 24-480VAC 25A SSR.

    This is my config file entry for heaters:

    
    ; Heaters
    M308 S0 P"temp0" Y"thermistor" A"Bed Temp" T100000 B4725                   ; configure sensor 0 as PT1000 on pin temp0
    M308 S1 P"temp1" Y"thermistor" A"Extruder Temp" T100000 B4725                   ; configure sensor 1 as PT1000 on pin temp1
    M950 H0 C"out0" T0                                 ; create bed heater output on out0 and map it to sensor 0
    M950 H1 C"out1" T1                                 ; create nozzle heater output on out1 and map it to sensor 1
    M307 H0 B0 S1.0                                 ; Set PID for bed heater
    M140 H0                                            ; map heated bed to heater 0
    M143 H0 S100                                       ; set temperature limit for heater 0 to 100C
    M307 H1 B0 S1.0                                   ; Set PID for Hotend .4Bmm nozzle
    M143 H1 S260                         ; Set temperature limit for heater 1 to 260C
    M308 S2 P"mcu-temp" Y"mcu-temp" A"Duet Board" ; Configure MCU sensor
    
    

    The SSR is wired as:
    Output 1 + wire to the bed
    Output 2 110v source
    Input 3+ Duet3 out0 +
    Input 4- Duet3 out0-

    The other wire from the bed goes to neutral on the power supply. I know you're supposed to connect the source voltage for Out0 to Out0 power in but I know it's max voltage is 36v. What do I need to do to get this setup working?



  • Surely the other wire from the bed should go to the 110V neutral rather than the power supply neutral? Unless I'm not reading the description properly.

    For OUT0 you should be able to drive the relay without a problem, just make sure the voltage is in the level the relay expects for input signal, and connect that voltage to OUT0 power in.

    You should just jump the vin power and ground to OUT0 POWER IN if your relay can take the voltage. You can post what relay you are using to be sure.


  • Moderator

    Sorry I'm a visual person, can you post a photo of your wiring for clarity?

    The SSR is switching the 110v for the bed. The duet switching voltage going to the SSR will be whatever your VIN is on the Duet.



  • @PhaedruxCube Bed Wiring.png

    Here's a quick half attempt at a wiring diagram.



  • @Phaedrux This is the way it was setup with my Duet 2 Wifi before switching to Duet 3. I also have it setup the same way on my other printer with a Duet 2 Wifi. The idea was the 110v to the bed wasn't always live for safety reasons.


  • Moderator

    What what do you have wired to Out0 Power In?



  • @Phaedrux Nothing, and I know that's one of my issues. Obviously the SSR isn't getting any voltage to turn on and heat the bed. However I can't connect 110 directly to the board. I'm wondering if I should remap and use Temp2 or what other options I have.


  • Moderator

    Normally you would bridge Out0 Power In with the VIN connectors or run a seperate line back to the 12/24v PSU. The SSR just needs a signal, not 110v from the wall, that's what the SSR is for. Using Out0 is fine, but you do need to provide power to Out0 Power In. In cases where the bed is getting the power from the Duet and not an SSR the Out0 Power In makes more sense because you might want to use a seperate PSU maybe of a different voltage or higher wattage to power the bed.

    Using another output is fine too, it would just be getting the signal voltage from vin anyway. And since you're just using it for signalling you don't need the beefy mosfet of Out0 anyway.


  • administrators

    Just connect the Out0+In terminal to the +VIN terminal. That's how I wired my Tool Changer, which uses a 240VAC bed heater controlled by a SSR.



  • Thanks guys. Based on what @Phaedrux said I remapped it to temp1 and moved extruder to temp2. Everything is working. Now I just need to figure out why my temp sensors are so off.


  • Moderator

    @dhusolo said in Duet 3 V1.0-SSR to power 110v bed heater:

    M308 S0 P"temp0" Y"thermistor" A"Bed Temp" T100000 B4725 ; configure sensor 0 as PT1000 on pin temp0 M308 S1 P"temp1" Y"thermistor" A"Extruder Temp" T100000 B4725 ; configure sensor 1 as PT1000 on pin temp1

    Are you using PT1000s?



  • @Phaedrux Not sure to be honest. I bought them off amazon. link



  • @dhusolo
    Those are 100k Thermistors... not PT1000 RTD's. You need to change your config.



  • @theruttmeister The comment says they're PT1000. I used the reprap configuration tool. I changed Y"PT1000" to Y"thermistor" but didn't change the comments. This is how my config file is after running PID tune a few times.

    ; Heaters
    M308 S0 P"temp0" Y"thermistor" A"Bed Temp" T100000 B4700 C0.0000000706                   ; configure sensor 0 as thermistor on pin temp0
    M308 S1 P"temp1" Y"thermistor" A"Extruder Temp" T100000 B4725 C0.0000000706               ; configure sensor 1 as thermistor on pin temp1
    M950 H0 C"out1" T0                                 ; create bed heater output on out0 and map it to sensor 0
    M950 H1 C"out2" T1                                 ; create nozzle heater output on out1 and map it to sensor 1
    M307 H0 A251.6 C1137.3 D11.0 V24.6 B0              ; Set PID for bed heater
    M140 H0                                            ; map heated bed to heater 0
    M143 H0 S100                                       ; set temperature limit for heater 0 to 100C
    M307 H1 A461.5 C202.9 D3.7 V24.6 S1.0 B0           ; Set PID for Hotend .4Bmm nozzle
    M143 H1 S260                         ; Set temperature limit for heater 1 to 260C
    M308 S2 P"mcu-temp" Y"mcu-temp" A"Duet Board" ; Configure MCU sensor
    
    

    The temp is closer to being accurate. Not sure if I have the correct value for Y"thermistor" or T100000. Now they're about 2C off from what my IR gun reads the temp at.


  • Moderator

    Try this instead and then PID tune the heaters. These are the default values for thermistor from the config generator.

    ; Heaters
    M308 S0 P"temp0" Y"thermistor" T100000 B4138 ; configure sensor 0 as thermistor on pin temp0
    M950 H0 C"out1" T0                           ; create bed heater output on out1 and map it to sensor 0
    M307 H0 B0 S1.00                             ; disable bang-bang mode for the bed heater and set PWM limit
    M140 H0                                      ; map heated bed to heater 0
    M143 H0 S120                                 ; set temperature limit for heater 0 to 120C
    M308 S1 P"temp1" Y"thermistor" T100000 B4138 ; configure sensor 1 as thermistor on pin temp1
    M950 H1 C"out2" T1                           ; create nozzle heater output on out2 and map it to sensor 1
    M307 H1 B0 S1.00                             ; disable bang-bang mode for heater  and set PWM limit
    M143 H1 S260                         ; Set temperature limit for heater 1 to 260C
    M308 S2 P"mcu-temp" Y"mcu-temp" A"Duet Board" ; Configure MCU sensor
    


  • @dhusolo said in Duet 3 V1.0-SSR to power 110v bed heater:

    Not sure if I have the correct value for Y"thermistor" or T100000. Now they're about 2C off

    2C off from room temp or hot hot? and does the IR gun correctly account for emissivity of the surface you're measuring?

    in any case sounds like Y and T values are correct.



  • @bearer 2C off at room temp. I know there will be a slight deviation between the sensor and the IR gun due to a few things. My bed has a surface mount thermistor. I have a build surface on a spring steel sheet and a magnet sticker holding it to the bed. I was considering 2C "close enough"



  • @dhusolo
    Given all the variables (like IR guns being terrible for measuring temps of metals) +-2C is great.

    Different question at 220C though...



  • @theruttmeister it's hard to get an accurate reading because my hotend is fairly enclosed and has a silicone sock on it. the bed was reading 59.5C when set to 60. I'm running calibration prints now so we'll see how it goes.


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