PT100 (E3D) wiring - 2 or 4 wires?



  • Hey all!

    On the E3D PT100 sensor it has 2 wires. Is it best to run those 2 wires into the daughterboard on 2 and 3, then bridge 1/2 and 2/3 as per documentation?

    I’ve also heard of using 4 wite extensions from the sensor back to the daughterboard. In this case, you can plug the 2 wires from one lead into blocks 1/2 and 2 wires from the other lead into blocks 3/4.

    Which setup is most preferable?

    Thanks!

    Nate



  • Hi @natewalck,

    How old is you daughter board? Mine has 2 black jumpers that did the bridging for you. You would want to jump 1 & 2 and 3 & 4. You can put one lead in either 1 or 2 and the other in 3 or 4.

    In regards to the 4 wire, it just makes them more accurate as a pt100 is still a resistance based sensor, and therefore will be effected by the resistance of the cable. The extra two wires are used to help compensate for that. Not sure how much effect it has on a short cable run like what we have as the cable resistance would be low. At work I deal a lot with submersible pumps, which have pt100’s in them for motor protection and as they can be up to 200m deep, we wire them up as either 3 or 4 wire types.

    Regards,
    Sam



  • Cool, makes sense. So even though the sensor itself is only 2 wires, running 4 back to the daughterboard makes it more accurate than using 2 wires and the jumper.

    I have the newest revision daughterboard.


  • administrators

    If you use long wires, or you will have connectors in the cable, then 4 wires is best. If the cable is short with no connectors except where you connect it to the PT100 and the daughter board, then 2 wires is sufficient.


 

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