3 wire RTD bolt on sensor wiring

[bdoutney]

There are 2 reds and a white wire in the sensor lead but the drawing shows the reds are in parallel. Does anyone know the purpose of this?

 

[Tharon]

I believe the 3 and 4 wire RTDs are used for ambient temp compensation. Or maybe it was to compensate for lead resistance. I forget exactly which. But they are wired in parallel when attached to a device with two wire inputs.

 

[JohnCalderwood]

http://www.minco.com/Sensors-and-In...ferences-between-2-3-or-4-wire-configurations

many articles from many companies...above is a reasonable one...

 

[Mickey]

More for your reading pleasure...

https://www.google.com/?gws_rd=ssl#q=rtd+tutorial+pdf

 

[Tom Jenkins]

The two red leads are connected at one end of the RTD resistor. The white lead is connectd to the opposite side of the resistor. The 2nd red lead is used to compensate for the resistance of the wiring, which improves accuracy. By measuring the resistance between the two red leads the resistance of the wires is measured and can be deducted from the total resistance. This leaves just the RTD element itself.