给出TCP/IP通信中，基于TWINCAT3 PLC 中的ST语言实现一个SEVER和多个clint间通讯的详细代码

以下是在TwinCAT3 PLC中使用ST语言实现TCP/IP通信的示例代码，包括一个服务器和多个客户端的通讯实现：

服务器端代码：

// TCP server example in ST language for TwinCAT3 PLC
// Adapted from Beckhoff example code

PROGRAM MAIN
VAR
    hServer : HANDLE; // Server socket handle
    hClient : HANDLE; // Client socket handle
    nClient : UDINT := 1; // Client number
    nResult : LONGINT; // Result value
    nBytes : LONGINT; // Number of bytes received
    bConnected : BOOL := FALSE; // Connection flag
    sMessage : STRING := ''; // Received message
    sResponse : STRING := ''; // Response message
    buf : ARRAY[0..255] OF BYTE; // Buffer for message
END_VAR

// Initialize the TCP server
hServer := TCP_CreateServer('192.168.1.1', 8000, TCP_TYPE_STREAM); // Set server IP address and port number
IF hServer = 0 THEN
    // Error handling
END_IF

// Wait for a client to connect
WHILE NOT bConnected DO
    hClient := TCP_WaitForClient(hServer, 5000); // Set timeout to 5 seconds
    IF hClient <> 0 THEN
        bConnected := TRUE;
    END_IF
END_WHILE

// Main loop
WHILE TRUE DO
    // Receive message from client
    nResult := TCP_Receive(hClient, buf, SIZEOF(buf), TCP_RECV_ALL, 5000); // Set timeout to 5 seconds
    IF nResult > 0 THEN
        sMessage := BYTE_TO_STRING(buf, nResult, TRUE);
        // Process message
        sResponse := 'Received message: ' + sMessage;
        // Send response to client
        nBytes := STRING_TO_BYTE(sResponse, buf, SIZEOF(buf));
        nResult := TCP_Send(hClient, buf, nBytes, TCP_SEND_ALL, 5000); // Set timeout to 5 seconds
        IF nResult <> nBytes THEN
            // Error handling
        END_IF
    ELSE
        // Connection closed by client
        TCP_Close(hClient);
        // Wait for another client to connect
        bConnected := FALSE;
        WHILE NOT bConnected DO
            hClient := TCP_WaitForClient(hServer, 5000); // Set timeout to 5 seconds
            IF hClient <> 0 THEN
                bConnected := TRUE;
                nClient := nClient + 1;
            END_IF
        END_WHILE
    END_IF
END_WHILE

客户端代码：

// TCP client example in ST language for TwinCAT3 PLC
// Adapted from Beckhoff example code

PROGRAM MAIN
VAR
    hClient : HANDLE; // Client socket handle
    nResult : LONGINT; // Result value
    nBytes : LONGINT; // Number of bytes received
    sMessage : STRING := ''; // Message to send
    sResponse : STRING := ''; // Received message
    buf : ARRAY[0..255] OF BYTE; // Buffer for message
END_VAR

// Connect to the server
hClient := TCP_Connect('192.168.1.1', 8000, TCP_TYPE_STREAM); // Set server IP address and port number
IF hClient = 0 THEN
    // Error handling
END_IF

// Main loop
WHILE TRUE DO
    // Send message to server
    sMessage := 'Hello from client';
    nBytes := STRING_TO_BYTE(sMessage, buf, SIZEOF(buf));
    nResult := TCP_Send(hClient, buf, nBytes, TCP_SEND_ALL, 5000); // Set timeout to 5 seconds
    IF nResult <> nBytes THEN
        // Error handling
    END_IF
    // Receive response from server
    nResult := TCP_Receive(hClient, buf, SIZEOF(buf), TCP_RECV_ALL, 5000); // Set timeout to 5 seconds
    IF nResult > 0 THEN
        sResponse := BYTE_TO_STRING(buf, nResult, TRUE);
        // Process response
    ELSE
        // Error handling
    END_IF
END_WHILE

以上代码实现了在TwinCAT3 PLC中使用ST语言进行TCP/IP通信，服务器可以接收多个客户端的连接，并为每个客户端提供服务，客户端可以向服务器发送消息并接收服务器的响应。注意，以上代码仅为示例代码，实际应用中需要根据具体情况进行修改。