Siemens PLC Serial communication mode

Three ways of Siemens PLC serial communication

time: 2015-10-25-14:31:55 Edit: Electrician section: Siemens PLC

Introduction: Siemens PLC serial communication Three ways, divided into RS485 serial communication, PPI Communication, MPI communication, free port mode Siemens PLC and the computer serial communication, S7-200 Series PLC communication port 3 kinds of working methods.

Three ways of Siemens PLC serial communication

1, RS485 serial communication
The majority of third-party equipment support, Siemens S7 PLC can choose the free port communication mode to control the serial communication. The simplest case is to send a message to a third-party device such as a printer or a frequency converter with a send instruction (XMT). In any case, it must be done through the S7 PLC programming program. When the free port mode is selected, the user can control the operation of the communication port by sending instruction (XMT), receiving (RCV), sending interrupt, receiving interrupt.

2. PPI Communication
The PPI protocol is the most basic communication method of S7-200CPU, it can realize communication through the original port (PORT0 or PORT1), and it is the default communication mode of s7-200 CPU. The PPI is a master-slave protocol communication, where the master-slave is standing in a token ring network. In the CPU user network read and write instructions, the network read and write instructions are running on the PPI protocol. Therefore, the PPI only on the main side of the program to write, the slave network read and write instructions do not make any sense.

3. MPI Communication
MPI communication is a simpler way of communication, the rate of MPI network communication is 19.2KBIT/S~12MBIT/S,MPI network support 32 nodes, the maximum communication distance is 50M. Communication distances can also be extended through repeaters, but repeaters also occupy nodes. MPI network nodes can usually hang s7-200, human-computer interface, programming equipment and so on. Original address: http://www.dgjs123.com/plc_siemens/5890.htm

Siemens PLC Serial communication mode