How many communication methods does Siemens PLC have?

author: chen

2023-08-03

Siemens PLC is one of the brands that many people often use, so today I would like to share with you how many ways to communicate with Siemens PLC when doing upper computer development. Here, we can explain from three aspects: serial port communication, Ethernet communication and OPC communication.

1. Serial communication

Siemens PLC supports serial port communication. In S7-200 and S7-200Smart, the serial port is directly integrated, but from S7-1200 to S7-1500, it is gradually canceled. If necessary, it can be added by means of expansion modules. The reason for this phenomenon is actually the inevitable result of industrial development.

The advantages of serial communication are simplicity and low cost, but the disadvantage is also very obvious, that is, the transmission efficiency is low.

The early serial communication of Siemens is mainly Profibus DP communication, but the upper computer cannot directly communicate with Siemens PLC through Profibus DP. Therefore, the serial communication scheme commonly used by Siemens PLC is as follows:

PPI communication: PPI communication is only for S7-200 and S7-200 Smart series PLC, other models do not support it.

ModbusRTU Master: Siemens PLC supports the Modbus protocol quite well. Here it refers to the PLC as the Slave (that is, the slave station), and the host computer as the Master (that is, the master station).

ModbusRTU Slave: This refers to the PLC as the Master (that is, the master station), and the host computer as the Slave (that is, the slave station).

2. Ethernet communication

Siemens PLC communication is still dominated by Ethernet communication. Many people may know that the two main proprietary protocols of Siemens are S7 protocol and Profinet bus, but Profinet is a bus protocol. As far as I know, C# cannot directly communicate with Siemens PLC. Take Profinet communication. Therefore, the Ethernet communication scheme commonly used by Siemens PLC is as follows:

S7 communication: Basically, it can be realized from S7-200 to S7-1500. There are many open source or commercial libraries to choose from, including //s7.net, pronodave, libnodave, sharp7, and you can also package the communication library yourself.

ModbusTCP Server: This refers to the PLC as the Server (that is, the server), and the host computer as the Client (that is, the client).

ModbusTCP Client: This refers to the PLC as the Client (that is, the client), and the host computer as the Server (that is, the server).

OpenProtocol Server: This refers to open TCP communication, where the PLC acts as the TCPServer (that is, the server), and the host computer acts as the TCPClient (that is, the client).

OpenProtocol Client: This refers to the PLC as TCPClient (that is, client), and the host computer as TCPServer (that is, server).

3. OPC communication

OPC communication is a commonly used communication method in industrial control. Here it mainly lies in the selection of OPC software and the selection of OPCDA and OPCUA. Therefore, the OPC communication scheme commonly used by Siemens PLC is as follows:

PC Access series: Siemens develops PC-Access software for S7-200,

PC-Access Smart software is provided for S7-200 Smart, OPCDA communication can be realized directly through these software.

Simatic Net series OPCDA: Simatic Net is the OPC software mainly promoted by Siemens, which supports the whole series of Siemens, mainly the OPCDA communication method here.

Simatic Net series OPCUA: The new version of Simatic Net also starts to support OPCUA, here is mainly the OPCUA communication method.

KepServer series OPCDA: KepServer is also a commercial OPC software, which has a very high usage rate in China. It also supports all series of Siemens, mainly OPCDA communication method here.

Simatic Net series OPCUA: The new version of KepServer also starts to support OPCUA, here is mainly the OPCUA communication method.