Standardization of Mainstream PLC Socket TCP Client Communication

1. Overview of PLC Socket TCP Client Communication:

In socket TCP client communication, the client first calls a system function to create a TCP socket, then initiates a connection request to the server at a specified IP address and port. A reliable connection is established through a three-way handshake. The communication protocol can be customized by the user, allowing developers to design data formats and interaction rules based on business needs, such as using specific headers to identify data types and lengths for efficient parsing. Once the connection is established, data transmission and reception between the client and server are carried out according to the custom protocol. After communication is complete, the client actively closes the socket connection to release resources. This model allows for flexible adjustments to protocol details based on technical requirements, but developers must handle data parsing and error handling logic themselves.

2. Implementing Socket TCP Client Communication in PLCs:

Different brands of PLCs have varying names for socket TCP client communication, connection commands, commands for sending data, and commands for receiving data, as detailed in the table below.

As can be seen, different brands of PLCs implement socket TCP client communication with different commands and programming. Therefore, it is necessary to standardize the programming of PLC socket TCP client communication, encapsulating the communication into function blocks, instruction libraries, or user libraries with the same input and output parameters for ease of use.

3. Standardization of PLC Socket TCP Client Communication:

Based on the actual situation of sending and receiving data in socket TCP client communication, we have defined the encapsulated function blocks, instruction libraries, or user libraries for various brands of PLC socket TCP client communication as shown in the figure below.

The meanings of the parameters in the function blocks, instruction libraries, or user libraries are shown in the table below.

4. Video Tutorials on Standardized Function Blocks for Mainstream PLC Socket TCP Client Communication:

1. Rockwell Micro850: