PT100 fault



  • Ok, on my duplicator 6 I have a PT100 temp sensor going to the PT100 board (plugged in on the right side) with the left channel I have the resistor that came with it. I have the PT100 PCB screwed down tight and ensure the connection everywhere is secure. I even ran a heat soak at 260 degrees and it worked perfectly. Now when I print, at the same point on every print I get a heater fault and the temperature is 2000. the only way I can clear it (that I know of) is to turn the printer off or issue a "stop" command and it works properly again.

    The question is this:

    a) noise issue
    b) daughterboard issue
    c) PT100 issue
    d) my bad luck with these printers this month?

    I don't have the conn_SD connection going to my paneldue. Its literally the exact same point every time.



  • May wanna upload your config.g and show a pic of wiring.



  • Actually I saw in an earlier post someone talked about noise from the cooling fan being a problem and it appears changing my PWM from 500 to 10 solves the problem. I can see the noise on the temp measurement graph, but at least I can print without a fault now.

    I have a shielded PT100 cable for an ultimaker 2 coming to see if that can further help.



  • @bpislife said in PT100 fault:

    Actually I saw in an earlier post someone talked about noise from the cooling fan being a problem and it appears changing my PWM from 500 to 10 solves the problem. I can see the noise on the temp measurement graph, but at least I can print without a fault now.

    I have a shielded PT100 cable for an ultimaker 2 coming to see if that can further help.

    Using twisted pair cables for the PT100 should do the trick I used to have this issues when I used std wire and ran it in the same bunch as a motor!



  • Now im facing similar ussue - heater fault.. print stops more or less on the same place.
    Temperature does not show 2000, but very very slowly falls down.

    I already changed
    * heater
    * sd card
    (both did not help).
    also upgraded to 2.0b1 RTOS but that did no resolve the issue.

    i was thinking of PT100 fault, but later measured hotend temp with laser - measurement was more or less consistent with pt100 reading.

    this weekend ill change cabling... if it does not help i even do not know what to think...

    link to related forum thread

    i never thought of EM noise, but thought of some kind of a bug in heating algorithm in HW/FW...



  • I had this problem before buying Duet with RAMPS. I used PT100 amplifier board and the problem was that I put the board directly on the head and bundled all possible negative wires together. When moving to Duet I separated ale negative wires and my PT100 is connected using 4 wires. Now I don't have any problems.

    Maybe this will you point somewhere.



  • @dragonn 4-wire will be the best thing I do prior to installing the shielded PT100 just to see if the noise improves. The issue is that I am using the ribbon cable that came with the duplicator and I think it is causing more issues then not.



  • Ok, so just to update, I went from having tons of noise and heater faults to the signal looking smooth by using the 4 wire hook up with twisted leads. It is super easy to setup. I bought the wire already twisted (link below) and soldered the pair to each end of the PT100. Now with the FAN back at the normal frequency I see zero ripple in the measured temp.

    https://www.amazon.com/gp/product/B00B887D80/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1


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