Control an external temperature controller with Duet 2



  • I have an external temperature controller (a Watlow Anafaze mls300) that I want to use for a 3D printer that I am building. I want to use this because I need to control 6 heaters with K type thermocouples and I already have the temperature controller. Is it possible use the Duet 2 to tell the controller the temperatures and have the temperature controller do the actual work?

    The temperature controller is set up to be controlled with an RS232 port right now, so I think this should be possible, but I don't really even know where to start.

    Please help!


  • administrators

    If the interface on your temperature controller really is RS232 then it has signal levels of about +/-10V and you would need a converter to level shift the signal for the Duet, which has 3.3V signal level. You would then be able to use M118 P2 to send messages to it to set the temperature.



  • Thank you for your help!



  • @dc42 aside from the converter, what would the easiest way to do this be? Would the expansion header breakout board be useful?


  • administrators

    @BismuthBlues said in Control an external temperature controller with Duet 2:

    @dc42 aside from the converter, what would the easiest way to do this be? Would the expansion header breakout board be useful?

    No, the expansion breakout board only level shifts 5 extra stepper channels and 2 heater/servo channels, not the serial I/O channels.

    If your controller really does want 10V RS232 signals then you could use a converter such as https://www.sparkfun.com/products/449 or https://www.sparkfun.com/products/11189 powered from 3.3V.



  • @dc42 Thank you for your continued help on all of this. After doing some reading of the temperature controllers manual, I have found that I can configure it to be controlled either via EIA/TIA-232 or EIA/TIA-485. The controller also supports three different communications protocols; Modbus RTU, Anafaze (which I am assuming is the manufacturer's protocol) and Allen Bradley.

    I am pretty new to all of this so I am not really sure what the easiest way to go about things is, so any help is greatly appreciated.

    For the time being, I am using the controllers interface, but ideally, I would like to control the temperatures though the Duet.

    Thank you again for your help


  • administrators

    @BismuthBlues said in Control an external temperature controller with Duet 2:

    The controller also supports three different communications protocols; Modbus RTU, Anafaze (which I am assuming is the manufacturer's protocol) and Allen Bradley.

    I'm sorry, although I have come across Modbus before, I am not familiar with any of those protocols.


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