How can you control 4 heating mats/beds on a Duet2 Wifi
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So, my heating bed has a size of 800x800 mm. This is to be heated with 4 heating mats (400x400mm) at 24 volts and 400 watts.
For this I have provided 4 power supplies 24 V with 1000 W each. The power supplies should be controlled via the 4 Mosfets. And the mosfets are controlled via the board Duet2 Wifi or two PT100 daughterboards.
Now my question is how to wire the whole thing: the sensors from the bed to the daughterboards and then? Is there a way to set up 4 outputs to the mosfets (hardware module)? or can I just switch all the beds in parallel with just one thermistor? -
Is there a reason you went with 24v rather than mains powered beds? If it's not too late it would be worth considering switching to mains powered heaters.
Do you have just the Duet2 or do you also have a Duex5?
It would be easiest to add a Duex5 for the additional outputs.
https://docs.duet3d.com/Duet3D_hardware/Duet_2_family/DueX2_and_DueX5
Though you may be able to tap into the expansion header heater pins on the Duet2 to use to signal the mosfets since they don't actually need to carry any current.
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@phaedrux Many thanks for the answer!
I looked at the description of the DuEx5 and would also buy it. What strikes me is that although these are extensions for additional print heads or motors, they are not intended for heating beds. You can also see that in the configuration tool, if I add the DuEx5, I can add nozzles but only a heating bed.
That will then also be an issue when printing. In the end I can only specify one temperature for the bed...I'm willing to buy hardware and leave others out....I just need a plan on how other large printers with multi-part beds use a Duet2. -
@axiom the configuration tool provides a basic setup; it can’t configure complex setups. For that, you will need to configure RRF for your specific machine.
As you controlling the beds individually with Solid state relays, these take very little current to operate, and can usually be controlled by any output pin. Though if you want PWM control, you’ll need to use a heater or fan output. Then you can setup the heated beds for individual control. See https://docs.duet3d.com/User_manual/Connecting_hardware/Heaters_bed
Alternatively, you can combine the temperature sensors into one sensor; the reported temperature will be averaged across the sensors. See https://docs.duet3d.com/User_manual/Connecting_hardware/Temperature_connecting_thermistors_PT1000#using-multiple-temperature-sensors-for-a-single-heater
Ian
