PT1000 Sensor: 4.7k to 1k resistor swop question



  • I found a Pt1000 resistor on aliexpress that is made to fit in an e3d heat block. It also comes with 1k resistors that it says should be used to replace to 4.7k thermistor resistor if I want to achieve higher resolution with the PT1000.

    Question: I know I can find the location of the thermistor resistors through a little investigation on my board. but it is a bit annoying to do that while the board is all wired up.
    Does anyone have a picture/ diagram of the resistor locations for the thermistors?


  • administrators

    The Duet WiFi/Ethernet work quite well with PT1000 sensors using the existing 4k7 series resistor, because the ADC has 12-bit hardware resolution rather than the 10-bit resolution of 8-bit boards. So try it without changing the resistors first.

    If you do decide to change them, then 2.2K is more optimal than 1K. We changed to 2.2K resistors on the Duet 2 Maestro for this reason. 1K resistors give optimal resolution at 0C but the resolution drops off at higher temperatures.

    See the link on the wiki hardware page for the link to the schematic, which will give you the component identifiers for the series resistors.



  • Thank you for the quick reply! I will definitely check it out plug and play first.
    I've make a little diagram of where I believe the resistor is located cause I'm stuck at work right now but did I circle the right ones?

    0_1525099111362_Duet_thermistor_4.7k_resistor_diagram.jpg


  • administrators

    Yes, R19 and R53.


 

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