It shows the components of the circuit as streamlined forms as well as the power and also signal links between the tools. Rtd theory page 3 2 wire construction is the least accurate of the 3 types since there is no way of eliminating the lead wire resistance from the sensor measurement. 1 convert to 3 wire circuit which will essentially eliminate the ambient temperature effects 2 convert to a 4 wire circuit in this case connection lead resistance effects completely eliminated.
