C语言Modbus串口通信示例：读取电压值

{"title":"Cè语言Modbus幂口通信示例：读取电压值","description":"本示例演示了使用Cè语言进行Modbus幂口通信，通过发送Modbus命令读取电压值，并说明了每行代码的功能和作用。","keywords":"Cè语言, Modbus, 幂口通信, 电压值, 示例, 代码说明","content":"HANDLE hSerial;

void openSerialPort() { hSerial = CreateFile("COM1", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

if (hSerial == INVALID_HANDLE_VALUE)
{
    printf("Failed to open serial port\n");
    exit(1);
}

DCB dcbSerialParams = { 0 };
dcbSerialParams.DCBlength = sizeof(dcbSerialParams);

if (!GetCommState(hSerial, &dcbSerialParams))
{
    printf("Failed to get serial port state\n");
    exit(1);
}

dcbSerialParams.BaudRate = CBR_9600;
dcbSerialParams.ByteSize = 8;
dcbSerialParams.StopBits = ONESTOPBIT;
dcbSerialParams.Parity = NOPARITY;

if (!SetCommState(hSerial, &dcbSerialParams))
{
    printf("Failed to set serial port state\n");
    exit(1);
}

}

void closeSerialPort() { CloseHandle(hSerial); }

void sendModbusCommand(const unsigned char* command, int length) { DWORD bytesWritten; WriteFile(hSerial, command, length, &bytesWritten, NULL); }

void receiveModbusResponse(unsigned char* response, int length) { DWORD bytesRead; ReadFile(hSerial, response, length, &bytesRead, NULL); }

int main() { openSerialPort();

// 构建要发送的Modbus命令帧
unsigned char modbusCommand[] = { 0x01, 0x03, 0x00, 0x00, 0x00, 0x02, 0xC4, 0x0B };

sendModbusCommand(modbusCommand, sizeof(modbusCommand));

// 接收Modbus响应
unsigned char modbusResponse[256];
receiveModbusResponse(modbusResponse, sizeof(modbusResponse));

// 处理Modbus响应，获取电压采样值等信息
// ...

closeSerialPort();

return 0;

}