Can a two-wire RTD be used with a three- or four-wire instrument?

The use of two-wire resistance temperature detectors with three- or four-wire instrumentation depends on the application, as this configuration adds additional uncompensated resistance to the system and seriously impairs the accuracy of the RTD. Consult the manufacturer for the proper RTD to use with its instrumentation for specific applications.

The two-wire RTD is used in applications where the heat caused by lead wire resistance is a constant and is offset by the instrumentation, and three- and four-wire RTDs use extra wires to manage the problem. The four-wire RTD typically uses wires two and three as potential leads to cancel out lead wire resistance for the highest level of accuracy.