How to wire up the Heatbed when using a MKS MosFET?

  • Hello everybody,

    I upgraded my heatbed because the stock version that came with my printer would distribute the heat very unevenly across the bed.
    I now use a different Heater which came with a MKS MOSFET like the one available here:
    The webpage explicitely discourages from connecting the MOSFET to the Bed Output (though they are talking about a RAMPS board there, I assume this applies to any board).
    I couldn't figure out any other Header that simply breaks out the Bed Heater Signal on the Duet3D WiFi, so any help on how to wire the MOSFET up would be greatly appreciated.


  • @t0bias Suggest you post the specification of the heater you've bought, and also details of yiur power supply - i.e. 12 or 24v. Depending on the wattage, you may be able to connect it directly to the Duet but if you post details, someone will be able to advise.

  • Thanks for your reply!
    So, the Printer is a Solidoodle 2 Pro, powered using a 12V 4.5A Supply.
    The new heatbed is a Prusa MK2b bundled with a 24V, 120W PSU, the MOSFET mentioned and a borosilicate glass plate.

  • The Duet's FET will be plenty for that heated bed, just connect it directly.

  • administrators

    @elmoret @t0bias I guess you want to use the MOSFET so you can continue to use 12V on the Solidoodle and use 24V on the heatbed?

    I am not sure why the MOSFET should not be connected to the bed output unless it could not handle 12V on the gate. Looking at the web page it says:

    1. Can use hot bed output signal of Ramp1.4 and MKS series to control .
    2. Can use digital signal of 5-24v to control .

    So it should be fine to connect it to the bed output of the Duet.

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