4 Zone heating Bed

darylprice

I have built a 3d Printer with a 4 zone heating area. I am powering with an external PSU. I am using SSR's for triggering from the Duet3D 6HC board. I need some assitance connecting these and setting up the Gcode..
Currently I am using the Mosquito Magnum plus hot end which is using Out-1 and Out-2. I can use the Out-3 for one trigger, but not quite sure how to connect the Out-4,5, and 6 since they have more pin outs.
Also I am using creality thermistors for the 4 areas. Temp-0 is used for the hot end, which only leaves 3 left for temperature management. I know there is a way to use other pins, but I cannot find out how to do this. Any help would be appreciated.

Thank you,
Daryl

droftarts

@darylprice As far as I know, there aren't any other pins on a 6HC you can use as thermistor/PT1000 temperature inputs (it's only on Duet 2 WiFi/Ethernet you can do this, and even then you need extra circuitry). However, you can use one or two temperature daughterboards to add more temperature inputs, though these will need to be PT100 or Thermocouples. You can connect DHT22/BME280 temperature sensors to the temperature daughterboard connector, but these are only suitable for measuring air temperature. Perhaps switch the Mosquito Magnum to use PT100/thermocouple, and use thermistors/PT1000 for the beds. For the full range of supported temperature sensors, see https://docs.duet3d.com/User_manual/Connecting_hardware/Temperature_choosing

If this doesn't work for you, the only other option is to add a CAN board with a thermistor/PT1000 input to control the last bed. A Duet 3 Expansion 1XD or Duet 3 Toolboard 1LC would give you the extra temperature input and allow control of the SSR.

For the heated beds, yes you can control an SSR from the OUT4-9. Choose an appropriate voltage for the SSR control by putting a jumper on the 3-pin OUT4-OUT6_SelectV jumper, which can supply OUT4-6 with either VIN or 12V. SSRs usually accept signals from 3.3V to 32V, but check the specification of the SSR. Connect the +ve side of the SSR control to the V_OUTLC1 pin on the chosen header (eg OUT4), and connect the -ve side of the SSR to the out4 pin (which switches to -ve/GND). Configure in the same way as you have OUT3. Note the M950 Q parameter sets the PWM frequency for the SSR, check the SSR specification for how quickly it can switch. See this section and the section after for DC and mains powered bed recommendations: https://docs.duet3d.com/en/User_manual/Connecting_hardware/Heaters_bed#bed-heater-driven-using-a-solid-state-relay

Ian

dc42

@darylprice FYI we are looking to make a new CAN expansion board to support just inputs, outputs (typically to drive SSRs) and sensors; however we don't yet have a target production date for it.

darylprice

@dc42
Thank you

darylprice

@droftarts
Thank you