1. Introduction to basic information of serial communication module CP340/CP341/CP440/CP441-1/CP441-2 modules are serial communication modules in Siemens S7-300/400 series PLCs. These modules have one or two (CP441-2) serial communication interfaces (RS232C, 20mA-TTY or RS485/422). These communication modules can be used to exchange data between S7-300/400 systems and other serial communication devices such as printers, scanners, smart meters, third-party MODBUS master and slave stations, Data Highway, inverters, and USS stations. 2. Serial communication module and ordering information 3, matters needing attention: 3.1 When implementing MODBUS communication, it is necessary to insert the hardware dog of the corresponding protocol on the CP341/CP441-2 module (hardware dog, Dongle, protocol driver or Loadable driver refers to the same thing). 3.2 MODBUS is a single master station serial communication protocol. There can only be one MODBUS master station in the system, and only data exchange between the master station and slave station can be realized. Data exchange between slave stations cannot be performed. 3.3 RS232C interface communication maximum distance is 15m; The maximum communication distance of RS422/485 interface is 1200m. 3.4 The serial communication template only has three types of electrical interfaces: RS232C, 20mA-TTY or RS485/422. To realize the optical fiber communication of the serial port, only third-party conversion equipment can be purchased. Siemens does not provide such equipment. Zhejiang Synmot Electrical Technology Co., Ltd , https://www.synmot-electrical.com
