Odd thermistor faults.
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I keep getting these spikes in my thermistor. I have verified wiring by mimicking the movements that I thought were causing this. After the print stops and I get back to temp it is a solid line again no more fluctation than .4 degrees. Any ideas on what could be causing this?
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It is a very common failure mode - seen it many times and have a thermistor on my bed that is doing this (added a new thermistor for bed sensing but still display the old sensor data)
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@jens55 yeah this isn't a thermistor issue. All of my wiring checks out good. I actually found that my MCU temp was too high. I've got a fan on it now and it is holding strong.
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How high was your MCU temp?
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@phaedrux 50c I got it down and seems to be much better.
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@phaedrux it is down to 38 now
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Was your MCU temp reading calibrated?
https://duet3d.dozuki.com/Wiki/Calibrating_the_CPU_temperature
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@phaedrux is that a common thing if MCU temp is too high? What's acceptable?
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I've not heard of it before. It could be the MCU temp or some other component getting too hot perhaps.
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@phaedrux I'm guessing other stuff got too hot. Running good now that it's cooled.
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@wdenker said in Odd thermistor faults.:
@jens55 yeah this isn't a thermistor issue. All of my wiring checks out good. I actually found that my MCU temp was too high. I've got a fan on it now and it is holding strong.
As I said, it is a VERY common failure mode of thermistors. Got nothing to do with wiring although I suppose a teeny tiny portion of wiring faults could possibly present like that.
At 50C or whatever, has nothing to do with the MCU either!It is also a very random type of failure that shows up whenever the moon aligns with Alph Centuri and you got up on the left side of the bed tat morning. .... but hey, a fan doesn't hurt but don't expect that to fix the issue.
I suggest you replace the thermistor to see if it fixes things.
Peace ... out ...< drops keyboard and leaves the room> <heavy gesturing with arms to emphasize for proper drama purposes>
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@phaedrux well mcu temp helped for about an hour longer. i paused on the next blip and started back again and is solid.
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@phaedrux said in Odd thermistor faults.:
Was your MCU temp reading calibrated?
https://duet3d.dozuki.com/Wiki/Calibrating_the_CPU_temperature
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@phaedrux no but my infrared thermometer shows it is accurate.
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@phaedrux here is after a pause and resume and MCU showing 38c and infrared confirms 38c
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I think the MCU temp is a red herring.
The graph seems more like noise or interference. Or failing thermistor.
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@phaedrux thermistor was just replaced. I can replace again and see if I still have issues I suppose.
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Does any component on the board seem to be getting abnormally hot?
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@phaedrux extruder motor is.
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@wdenker my guess is it's noise from nearby wiring such as running next to a motor cable