Sensor wiring is consistently one of the most frequently asked questions by customers during the procurement process. Many customers are unsure how to connect sensors. In fact, the wiring methods for various sensors are basically the same. Pressure sensors generally come in two-wire, three-wire, four-wire, and some even have five-wire configurations.
Two-wire pressure sensors are relatively simple; most customers know how to wire them. One wire connects to the positive terminal of the power supply, and the other wire, the signal wire, connects to the negative terminal of the power supply through the instrument. This is the simplest method. Three-wire pressure sensors add an extra wire to the two-wire system, directly connecting to the negative terminal of the power supply, making it slightly more complicated. Four-wire pressure sensors always have two power input terminals and two signal output terminals. Four-wire sensors often provide voltage outputs rather than 4~20mA outputs; 4~20mA outputs are called pressure transmitters, which are mostly implemented as two-wire systems. Some pressure sensor signal outputs are unamplified, with a full-scale output of only tens of millivolts, while some pressure sensors have internal amplification circuits, providing a full-scale output of 0~2V. As for how to connect it to the display instrument, it depends on the instrument's range. If there's a range that matches the output signal, you can measure directly; otherwise, you'll need to add a signal adjustment circuit. Five-wire pressure sensors are not significantly different from four-wire sensors, and five-wire sensors are relatively rare on the market.