In the RS485 communication network, the master-slave communication mode is generally adopted, that is, one master has multiple slaves. In many cases, when connecting the RS485 communication link, simply connect the "A" and "B" ends of each interface with a pair of twisted pairs, and ignore the connection of the signal ground. This connection method is used in many The occasion can work normally, but it has buried a lot of hidden dangers. Reason 1 is common mode interference: the RS485 interface uses a differential mode to transmit signals, and it does not need to detect signals relative to a certain reference point. It is enough to detect the potential difference between the two lines, but it is easy to overlook that the transceiver has a certain common-mode voltage range. The common-mode voltage range of the RS485 transceiver is -7 to +12V. Only when the above conditions are met, the entire network to work properly;

RS485 can reach 1200 metres transmission distance, in such a long distance is susceptible to the influence of lightning, coupled to a very strong lightning energy, damage to communication equipment, for this Socay Company introduced a three-pole ceramic discharge tube to weaken the lightning energy.

Socay Electronics has rich experience in lightning surge protection, and widely uses ceramic gas discharge tubes for power supply and communication system protection.

Main parameters of SC3E8-230HSMD; breakdown voltage: 184V-276V, flow IPP up to 25kA, capacitance: less than 1.5pF. Working temperature: -40°C to 105°C, package: 8*7.9*10. This model is widely used, the following is the application circuit of this GDT.

It is widely used in smart instruments, agricultural and livestock integrated machines, dynamic environment monitoring systems, RS485 repeaters, RS485 serial servers, network IO controllers, and Modbus to Profinet gateways.

It can replace the models 3RP230M-8 and 3R230SD-8S of other manufacturers.