This section introduces four-wire, three-wire, and two-wire connection methods; each has its own advantages and disadvantages and is suitable for applications with varying precision requirements. Regarding wiring, temperature detection instruments primarily utilize the following configurations:
There are three main wiring methods for resistance temperature detectors (RTDs):
(1) Four-wire system: Wires are connected to both ends of the resistor element. A constant input current converts the resistance into a voltage signal, which is then transmitted to the secondary instrument via the other two wires. This method features symmetrical wiring that effectively eliminates thermoelectric effects, though it requires a precise input current of 1 mA.
(2) Three-wire system: One side of the resistor is connected to a wire, while the opposite side employs a different wiring configuration. Typically used in conjunction with a bridge circuit to minimize the impact of lead-wire resistance, this method is suitable for temperature monitoring in industrial production.
(3) Two-wire system: A single wire is connected to each side of the resistor. While this wiring method is simple, the signal path includes the lead-wire resistance-which varies based on the wire's material and length-making it primarily suitable for industrial applications where high temperature-detection precision is not required.
