The five core communication methods of Siemens PLC (Programmable Logic Controller) mainly refer to its commonly used communication protocols or interface methods,
which play a crucial role in the field of industrial automation.
Here are five main communication methods:
PPI communication
Definition: PPI (Programmable Peripheral Interface) protocol is the most basic communication method for Siemens S7-200 series PLCs.
Characteristics:Communication is carried out through the original port, using a master-slave structure.
The master station device is responsible for sending requests to the slave station device, which responds to the requests, but the slave station cannot actively send information.
Application: Mainly used for uploading and downloading programs in Siemens STEP7 Micro/WIN programming software,
as well as achieving communication between Siemens human-machine interface and PC.
RS485 serial communication
Definition: RS485 is a commonly used serial communication standard, widely used in industrial control and data acquisition systems.
Features: Using an unbalanced differential signal transmission method, allowing multiple devices to communicate on the same bus.
It has the advantages of strong anti-interference ability and long transmission distance.
Application: Siemens S7 PLC can control serial communication by selecting the free port communication mode
to send information to third-party devices such as printers and frequency converters.
MPI communication
Definition: MPI (Multi Point Interface) is a Siemens specific serial interface used to connect different Siemens devices.
Features: The communication speed ranges from 19.2kbit/s to 12Mbit/s, supporting up to 32 nodes and a maximum communication distance of 50m.
Application: Usually used to connect PLC, HMI (Human Machine Interface), programming devices, etc., to achieve programming and data transmission.
Ethernet communication
Definition: Ethernet is a network technology based on a shared public transmission channel.
Features: It has the advantages of high transmission speed, abundant network resources, strong system functions, simple installation, and convenient use and maintenance.
Application: Siemens PLC supports standard Ethernet communication and communicates with other devices or systems through TCP/IP protocol.
It is becoming increasingly common in modern industrial automation, commonly used to achieve data exchange and remote control between PLC and upper computer, human-machine interface, data acquisition system and other equipment.
The Ethernet communication of Siemens PLC usually uses Profinet protocol (Process Field Network) as the communication protocol.
Profinet is a real-time Ethernet communication protocol used for industrial automation, supporting high-speed data transmission and real-time control.
PROFIBUS communication
Definition: PROFIBUS (Process Field Bus) is one of the commonly used fieldbus protocols in the field of industrial automation.
Features: The transmission speed can be selected within the range of 9.6kbaud to 12Mbaud,
with the characteristics of internationalization, openness, and independence from equipment manufacturers.
Application: Used to connect control devices and field devices in automation systems, achieving high-speed data communication between PLCs and distributed peripheral devices.
PROFIBUS-DP (Decentralized Peripherals) is a subset primarily used for communication between PLCs and decentralized IO devices.