使用C语言编写一个通过socket使PC与三菱PLC通讯的程序

以下是一个简单的C语言程序，可以通过socket使PC与三菱PLC通讯：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib")

int main()
{
    WSADATA wsaData;
    SOCKET clientSocket;
    struct sockaddr_in serverAddr;
    char sendBuf[256];
    char recvBuf[256];
    int ret;
    int i;

    // 初始化Winsock库
    ret = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (ret != 0) {
        printf("WSAStartup failed with error %d\n", ret);
        return 1;
    }

    // 创建客户端socket
    clientSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (clientSocket == INVALID_SOCKET) {
        printf("socket failed with error %d\n", WSAGetLastError());
        WSACleanup();
        return 1;
    }

    // 设置服务器地址
    memset(&serverAddr, 0, sizeof(serverAddr));
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = inet_addr("192.168.1.1"); // PLC的IP地址
    serverAddr.sin_port = htons(5000); // PLC的端口号

    // 连接服务器
    ret = connect(clientSocket, (struct sockaddr*)&serverAddr, sizeof(serverAddr));
    if (ret == SOCKET_ERROR) {
        printf("connect failed with error %d\n", WSAGetLastError());
        closesocket(clientSocket);
        WSACleanup();
        return 1;
    }

    // 发送数据到PLC
    sprintf(sendBuf, "D100=%d", 1234); // 设置D100的值为1234
    ret = send(clientSocket, sendBuf, strlen(sendBuf), 0);
    if (ret == SOCKET_ERROR) {
        printf("send failed with error %d\n", WSAGetLastError());
        closesocket(clientSocket);
        WSACleanup();
        return 1;
    }

    // 接收PLC的响应数据
    ret = recv(clientSocket, recvBuf, sizeof(recvBuf), 0);
    if (ret == SOCKET_ERROR) {
        printf("recv failed with error %d\n", WSAGetLastError());
        closesocket(clientSocket);
        WSACleanup();
        return 1;
    }
    recvBuf[ret] = '\0';
    printf("Received: %s\n", recvBuf);

    // 关闭socket
    closesocket(clientSocket);

    // 清理Winsock库
    WSACleanup();

    return 0;
}

在这个程序中，我们使用了Winsock2库来实现socket通讯。程序首先初始化Winsock库，然后创建一个客户端socket，并设置服务器地址和端口号。接着，程序通过connect函数连接到PLC，然后通过send函数发送数据到PLC，并通过recv函数接收PLC的响应数据。最后，程序关闭socket并清理Winsock库。请注意，这只是一个简单的示例程序，实际的PLC通讯需要更多的代码来处理异常情况和错误处理。