I have a two wire RTD device that I am trying to connect to a 4 wire monitoring device. The interface from the monitor has 2 excitation pins and 2 sensor input pins.

What I am trying to figure out is what is the difference between individually connecting each of the pins to an 4-wire RTD sensor with 4 wires and using 4 wires that are spliced together in pairs closed to a 2-wire RTD device. Is there something special within the sensor of a 4 wire device that allows 4 lead wires to be connected, or are they simply joined into pairs within the sensor?

 

It's quite OK to use the 4 wires as you propose, the only error you will get is due to the resistance in leads between the RTD element and where you join to your pairs.

3 wires is the most common method of wiring RTDs.
4 wires are usually used where you require super accuracy.

If its only a few feet between the sensor and transmitter you can even just use 2.

Hope this helps.

Roy