Modbus TCP and Modbus RTU

Modbus TCP and Modbus RTU

　　 Modbus is a standard protocol for communication between industrial equipment. It is more commonly used in instruments and meters. Different devices can communicate with each other after complying with the Modbus standard. Modbus originally used serial links, such as RS232 and RS485/422. With the development of the network, the Modbus TCP standard was later introduced. Modbus of the serial link is divided into ASCII and RTU, among which RTU has high transmission efficiency and is used more. 2. Convert Modbus TCP to Modbus RTU.

 　　 With the popularity of the Modbus TCP and Mobus RTU protocols, there are more and more devices, and the demand for Modbus TCP to access Modbus RTU devices is increasing. Modbus TCP has its own advantages, because it can use existing network, internet and other facilities, and a large number of Modbus RTU devices already exist. Use a unified Modbus TCP client software to access all Modbus devices, unified and centralized management will greatly improve the integration of the system.

　　 Modbus RTU frame contains: address frame, function code, data, CRC check. The Modbus TCP data packet contains: MBAP header, function code, and data. The conversion of these two formats must be realized.