PT100 heater fault short

  • I got a message on heater channel X201 that I had a short. After some debugging I isolated the fault to the daughterboard itself:
    I repeated the fault with a brand new PT100 and new wiring
    The fault cleared when using the X200 channel.

    How precisely is the fault identified as a short by the system. Are there other problems that can give a false short indication?

    Using a multimeter over the pins of the daughterboard of the failing channel measures ~100Mohm without the heater (around 100 with) which is what I would expect.

    Is there anything I can do to further isolate and possibly fix the problem or will I need a new daughterboard?

  • administrators

    If you are certain that it's the daughter board that has failed, then I guess either the green reference resistor has burned out on that channel, or the sensor chip has. If the resistor looks ok, you could try replacing the chip. It's supposed to tolerate up to +/-45V on the PT100 inputs without damage.

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