Hello everyone, welcome to the star instrument class, in this issue we will talk about what is RS485 signal. In the low-speed, short-distance, non-interference occasions can use ordinary twisted pairs, on the contrary, in high-speed, long-line transmission, impedance matching (generally 120Ω) RS485 special cable must be used, and in the interference environment should also use armored twisted pair shielded cable.

(RS-485 communication cable structure diagram) When using the RS485 interface, for a specific transmission line, the maximum allowable cable length for the data signal transmission from the RS485 interface to the load is inversely proportional to the baud rate of the signal transmission, and this length data is mainly affected by factors such as signal distortion and noise. Theoretically, when the communication rate is 100Kbps and below, the maximum transmission distance of RS485 can reach 1200 meters, but the transmission distance in practical applications also varies depending on the transmission characteristics of chips and cables. In the transmission process, the signal can be amplified by adding the method of relay, and up to eight relays can be added, that is to say, the maximum transmission distance of RS485 can reach 10.8 kilometers in theory. If long-distance transmission is really required, optical fiber can be used as the propagation medium, and a photoelectric converter is added at both ends of the transmitter and receiver, and the transmission distance of multi-mode optical fiber is 5 to 10 kilometers, while the transmission distance of single-mode optical fiber can reach 50 kilometers. Star Meter Manufacturing Co., Ltd. is a high-tech enterprise integrating R&D, production and sales. Specializing in the production of pressure transmitters, liquid level transmitters, temperature transmitters, temperature and humidity transmitters, differential pressure transmitters, soil moisture transmitters, 3051 transmitters and related instrumentation accessories. A number of products under the Xingyi brand have obtained a number of patent certificates issued by the state, such as CE certification, IS9001 certification, SGS certification, TüV SüD certification, explosion-proof certification, etc. If you have any questions about product consultation, product customization, agency, technical inquiry, quotation, etc., please contact Xingyi: 400-600-4496!