The transmitter has four wiring terminals, which are generally divided into three types: two wire, three wire, and four wire. The two-wire system of the transmitter, which connects the power supply and load in series, has a common point, while the signal connection and power supply between the on-site transmitter and the control room instrument only use two wires. These two wires of the transmitter are both power and signal wires. The advantage of using a two wire system for the transmitter is its simple wiring. The two wire system uses a 4-20mA current output The three wire wiring method of the transmitter is to reduce the volume and weight of the transmitter, and improve anti-interference performance. Turn the power supply of the transmitter from 220V Change AC to low-voltage DC power supply, such as changing the power supply from 24V The use of DC power supply boxes creates conditions for negative line sharing due to low-voltage power supply, resulting in a three wire transmitter. The three wire system of a transmitter is to use one wire for the power supply, one wire for the signal output positive end, and one wire for the power supply negative end and the signal negative end. The voltage output (such as 0-10VDC, 0-5VDC, 1-5VDC, etc.) adopts a three wire wiring method. Two of the four wire output transmitters are power supply wires and two are signal wires. The power supply and signal work separately. On the basis of the three wire system, the transmitter has its own ground for the signal line and does not share the ground with the power line. The biggest feature of a four wire transmitter is its suitability for high-power transmitter equipment. The four wire system outputs RS485 digitally. If you have any questions regarding product inquiries, product customization, agency, technical inquiries, quotations, etc., please contact Xingyi at 400-600-4496!