windows c++ modbus RTU代码

以下是一个简单的Windows C++ Modbus RTU代码示例，使用了WinAPI的串口通信函数：

#include <windows.h>

#define SLAVE_ADDR 0x01
#define FUNC_READ_HOLDING_REG 0x03
#define START_ADDR 0x0000
#define NUM_REGS 0x0001

int main()
{
    // 打开串口
    HANDLE hCom = CreateFile("COM1", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
    if (hCom == INVALID_HANDLE_VALUE)
    {
        printf("Failed to open serial port!\n");
        return 1;
    }

    // 配置串口
    DCB dcb;
    GetCommState(hCom, &dcb);
    dcb.BaudRate = 9600;
    dcb.ByteSize = 8;
    dcb.Parity = NOPARITY;
    dcb.StopBits = ONESTOPBIT;
    SetCommState(hCom, &dcb);

    // 发送Modbus RTU请求
    BYTE request[8] = {SLAVE_ADDR, FUNC_READ_HOLDING_REG, START_ADDR >> 8, START_ADDR & 0xFF, NUM_REGS >> 8, NUM_REGS & 0xFF, 0x00, 0x00};
    DWORD written;
    if (!WriteFile(hCom, request, sizeof(request), &written, NULL))
    {
        printf("Failed to send Modbus RTU request!\n");
        CloseHandle(hCom);
        return 1;
    }

    // 接收Modbus RTU响应
    BYTE response[256];
    DWORD read;
    if (!ReadFile(hCom, response, sizeof(response), &read, NULL))
    {
        printf("Failed to receive Modbus RTU response!\n");
        CloseHandle(hCom);
        return 1;
    }

    // 解析Modbus RTU响应
    if (response[0] != SLAVE_ADDR || response[1] != FUNC_READ_HOLDING_REG || response[2] != NUM_REGS * 2)
    {
        printf("Invalid Modbus RTU response!\n");
        CloseHandle(hCom);
        return 1;
    }
    WORD value = response[3] << 8 | response[4];
    printf("Value: %d\n", value);

    // 关闭串口
    CloseHandle(hCom);
    return 0;
}

请注意，此示例仅针对单个寄存器读取，如果需要读取多个寄存器或进行其他操作（如写入寄存器），则需要修改请求和响应的格式，并根据Modbus协议进行处理。