Fluctuating temperature

Discussion in 'E3D-v6 and Lite6' started by Michael Kuebbeler, Jun 2, 2018.

  1. Michael Kuebbeler

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    Hi,

    I just build a Prusa i3 mk3 and swapped right from the start the Prusa supplied hotend by a new v6 hotend with Micro swiss heatbreak, copper heat block and PT100 sensor (without amplifier) and 24V 40 Watt heater cartridge (stock is 30W).

    Now, I see various issues:

    - when I select a target temp of 220, I see fluctuations, see the screenshot. The measured temp jumps between 220 and 150.
    - when I select aa highet temp, then this heavy fluctuation disappears.
    - Evene on warm up, the temp goes up to 145, stays there a while, and then suddenly jumps up to 216/218/220.
    - seems like the temp zone between 150-210 does not exist.
    - even when I set temp to 330, it goe sup to 218-225, but rarely touches the 330.

    Any input on those issues?

    Thx,

    Michael
     

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  2. elmoret

    elmoret Administrator

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    MK3 doesn't support PT100 without modifications like firmware/amplifier board.

    Also, seems odd to come to E3D for support when you've replaced most of the hotend with parts from other vendors?
     
  3. Michael Kuebbeler

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    I changed the firmware, and according to the firmware you can run PT100 without amploifier, at least there is a definition item. It also shows nozzle temperature at room temperature, so this seems to be working.

    The only thing that is not from E3D is the heatbreak, everything else is from e3D.

    Michael
     
  4. Michael Kuebbeler

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    ... also the heater cartridge I ordered from E3D. So only heatbreak is micro swiss.
     
  5. Ephemeris

    Ephemeris Well-Known Member

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    The rapid bouncing between 150 and 220C in your screenshot is interesting. If we take it face value, it suggests the resistance is rapidly changing by about 25 ohms. Hard to picture that being real given how repeatable it looks. I have to wonder if the firmware really works with the PT100. Or maybe it 'works' but not very well.
     
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  6. Antoine

    Antoine Well-Known Member
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    The Einsy that comes with the standard Mk3 should be able to work with a PT100, but only with an amplifier board, hence why it is available in the firmware. The standard heaters for the Prusa are actually 40W (If the wires are red then this is the case) as we supply these as well. The break was actually designed specifically for the Prusa machine, and you might see some drop in performance when you switch to another heatbreak.
     
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  7. Michael Kuebbeler

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    Thank you Antoine. Yes, the wirs are red, so great, it is 40w. Then I will test the PT100 with amplifier board.
     
  8. Michael Kuebbeler

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    Antoine, would you disclose what's so special on the Prusa mk3 heatbreak from e3d?
     
  9. Michael Kuebbeler

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    Just to close this topic:
    I have connected the amplifier board and I needed to figure out, how to connect the 3 wire output, but now it works extremely accurate and stable.

    Michael
     
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