Trouble with tool heater



  • I just started getting a second tool working on my tool changer. I have a duet 6HC with a 3HC expansion.
    I am using two Hemeras with pt1000 sensors.

    I have had a lot of good prints using 1 tool. I just added a second tool and I seem to get random tool faults, I have no idea what the fault is there are no temperature spikes on the graph and nothing I seem to do will actually log any information about what is causing heater fault.

    Side note it appears there is no way tune a tool heater attached to a 3hc board I am wondering if this has something to do with the fault as I don't k ow what to do to get tuning parameters.



  • @Miasmictruth Most likely it just needs tuning but as you've discovered, that is one of the things that hasn't yet been implemented for expansion boards. What I did was temporarily connect the heater to the main board, tune it, make a note of the parameters, then reconnect it to the expansion board and change config.g accordingly.
    Edit. Of course, this involves extending the heater and temperature sensor wires. If using a daughter board, you'll have to move that too.


  • administrators

    I tuned the Hemera tool on my Tool Changer using a mixture the manual method described at https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control#Section_Setting_the_model_parameters_manually and a dead time value from other E3Dv6 hot ends. The values I ended up were:

    M307 H4 A452 C235 D5.5 V24.0

    The V parameter should be replaced the tool board VIN voltage as reported by M122 B# (where # is the CAN address of the tool board) when the heater is operating.



  • Thanks for the replies! I was thinking about doing something along those lines. I guess I will have to make a temporary harness, I have an idea on how to do that without too much grief, then I will have something I can move from tool to tool as necessary. Also Thanks @dc42 for pointing out the M122 command I very likely would have missed that.

    If I still have an issue after this tuning method, is there something i can do to get some sort of fault diagnostic message on what is causing the heater fault?



  • Ok, I think I see the issue now. I tuned the hotends and retried printing again and had heater faults. It seemed to primarily happen in the dock.

    At some point I realized that the the fans are cooling the nozzle (it does have a silicone sock) and that this cooling effect must be amplified but the air getting redirected in the dock which is causing the heater fault.

    So now I am wondering:
    First should I tune the heater with the print fans running?

    Second, I can turn the fan off before it docks, but how do I turn it on? I could hard code the macro to always turn it on but I would like it to turn on only when needed.

    I could probably put this in the slicer manually but I dont see an option to so it automatically in the slicer (prusa slicer) anyone have thoughts on that?

    Thanks!


  • Moderator

    @Miasmictruth said in Trouble with tool heater:

    First should I tune the heater with the print fans running?

    This is usually a good idea. And you may not have to worry about Number 2.


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