RTD wiring, red-red-white

[sllindblom]

I am using a SCC-2345 and SCC-RTD01 modules.  I have tested the system with NI's Pt100 RTDs, and everything works OK.  My application is using three wire pt100 RTDs that are wired red-red-white, not the red-white-white of the NI RTDs.  Should I just reverse the red and white in the wiring diagram, or should the wiring be done differently?

[Henrik_Volkers]

As a first guess YES

at least if it's wrong you get an error or really high readings

To be shure you can measure the ressistances between the wires: the same colored should give a low reading <1Ohm (depends on cable) and the two other will give 100(+x)  Ohms. Compare it with the NI one and you have it.

[Otis]

Hi,

Actually, it shouldn't matter because an RTD is just a resistive device.  We simply use a known current to create a readable voltage that lets us know what the resistance is.

For more details on RTDs go here.

You can just do as you suspect and change the Reds to Whites (or Blacks) and you should be fine. Or you can just leave it as is and just connect your Reds to pins 6 and 4 and your White to pins 5 and 3.

Regards,