What is the maximum distance for 485 communication?

This post was last edited by mutianly on 2020-8-5 at 10:15. The maximum transmission distance for the Industrial 485 bus is 3000 meters. 　　RS-485 uses balanced transmission and differential du reception, thus it has the ability to suppress common-mode interference. Furthermore, the bus transceiver has high sensitivity, capable of detecting voltages as low as 200 mV, allowing the transmitted signal to be recovered over distances of several kilometers. RS-485 operates in half-duplex mode, with only one point able to transmit at a time; therefore, the transmission circuit must be controlled by an enable signal. RS-485 is very convenient for multi-point interconnection, as it allows many signal wires to be eliminated. By using RS-485, a networked distributed system can be created, which allows up to 32 drivers and 32 receivers to operate in parallel. The maximum transmission speed of RS-485 is 10 Mbps. The length of balanced twisted pair is inversely proportional to the transmission rate; only at rates below 100 Kbps is it possible to use the specified maximum cable length. The highest transmission rate can only be achieved over very short distances. Generally, the maximum transmission rate for a 100-meter long twisted pair is only 1 Mbps. The standard maximum transmission distance for the RS-485 interface is 4000 feet (about 1219 meters), although in practice it can reach 3000 meters. At greater distances, it affects the transmission rate. In reality, it is affected by various factors such as the environment and cable installation interference; generally, performance becomes unstable beyond 1200 M.