Stepper temp sensing for Duet2 WiFi PWM fan?



  • I've got a stepper riding on my Rostock Delta effector as an extruder. Homes and deck calibrates superbly.
    Sporty fan + shroud mounts on top of the stepper and runs the wire bundle to the Duet above.
    Currently running the fan from PWM2 on the Duet, with no variable control for when it runs(on all the time right now).
    config slice:
    M106 P0 H-1 ; PART-DRYING fan
    M106 P1 T30 H100:101:102:103 S127 ; DUET CPU fan
    M106 P2 S100 ; LDM fan

    M563 P0 D1 S"LDM_01" ; create a named tool using extruder drive 0
    //This is the motor I'd like to trigger the fan coming on for//

    IDEAL choice would be to have the gcode drive the fan whenever the E0 or E1(whichever is driving the extruder stepper) is energized/running)
    Thing starts to print, fans stays on, no sensor required.
    1_1558994687386_IMG_20190527_113719.jpg 0_1558994687386_IMG_20190527_113701.jpg
    Second choice is to mount a thermistor?/sensor (LM35?) in the mount/heatsink and wire it to the Duet.
    Can I even do that without a board to manage the signal?

    What d'y'allses think, ehhh?

    0_1558996491293_IMG_20190521_232936.jpg



  • Why does the motor get so hot that it needs a fan to cool it?



  • It may not need it, but the guys that engineered the setup added it, SO,
    I'm guessing it needs it.
    Now, that said, I just swapped the stepper for one with about 1.5x the torque capability...might solve all(?).
    Stepper is driving a (reverse archimedes-action )screw within the body and pushing clay out the nozzle, not melted plastic.
    Probably the reason?

    Haven't had the chance to crank it all up yet!



  • That might explain it...



  • Does anyone know how to set the config to turn on a fan when the E0 / E1 gets activated?



  • You could turn it on at the start of the gcode file by adding the command to the slicer start gcode. Assuming you still use a slicer?



  • I must need sleep; no gcode needed when, CLEARLY, the fan comes on when the machine starts, and then has no reason to turn off because the thing is extruding until the model is printed.
    At which time it will get shut off when I turn the machine off.

    Sensor version will be interesting.
    I found some LM35 sensor boards online that are remarkably low-priced, so if I go the temp sensing way it's looking pretty simple, as I just discovered the E0 / E1 temp connections on the Duet! Awesome.
    Plug-n-play??
    We'll shall see about that

    in later episodes



  • Wouldn't this work just like any other hot-end fan then? If you really want it controlled by thermostat an NTC or PT1000 is the easiest way to connect to the duet, maybe you can make the voltage output from the LM35 work, but thermistors are definitively plug and play.


  • administrators

    @nurbie said in Stepper temp sensing for Duet2 WiFi PWM fan?:

    Does anyone know how to set the config to turn on a fan when the E0 / E1 gets activated?

    How about making it controlled thermostatically by the heater(s) associated with those extruders, on the assumption that if you are doing continuous extrusion then the heater(s) must be hot? Edit: I didn't spot that you were using a clay extruder.

    You can connect an additional thermistor to the Duet and use that to control the fan instead, if you have any spare thermistor inputs. If not, you can use one of the thermistor inputs on the expansion connector plus a 4K7 pullup resistor to VRef. Configure it in M305 as a virtual heater.



  • I was under the impression there is no heater in use with the clay extruder. As such the inputs should be free to add thermistors.

    I still think it would be a useful feature to assign a fan linked to any/all enabled stepper driver or active heater output for cooling fans in the electronics enclosure, instead of thermostatic control off the CPU temperature or a dedicated thermistor.


 

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