106 lines
3.3 KiB
C#
106 lines
3.3 KiB
C#
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public static class ModbusHelper
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{
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// 生成写单个线圈(功能码05)的Modbus指令
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public static string GenerateWriteSingleCoilCommand(byte deviceAddress, ushort coilAddress, bool value)
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{
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byte[] command = new byte[6];
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command[0] = deviceAddress;
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command[1] = 0x05; // 写单个线圈功能码
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command[2] = (byte)(coilAddress >> 8);
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command[3] = (byte)coilAddress;
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command[4] = value ? (byte)0xFF : (byte)0x00;
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command[5] = 0x00;
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// 计算CRC校验
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ushort crc = CalculateCRC(command, 6);
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byte[] crcBytes = BitConverter.GetBytes(crc);
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// 组合完整命令(包含CRC校验)
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byte[] fullCommand = new byte[8];
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Array.Copy(command, fullCommand, 6);
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fullCommand[6] = crcBytes[0]; // CRC低字节在前
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fullCommand[7] = crcBytes[1]; // CRC高字节在后
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// 转换为十六进制字符串
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return BitConverter.ToString(fullCommand).Replace("-", "");
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}
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// 验证Modbus响应是否有效
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public static bool ValidateResponse(string command, string response)
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{
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if (string.IsNullOrEmpty(response) || response.Length < 8)
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return false;
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// 解析响应字符串为字节数组
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byte[] responseBytes = StringToByteArray(response);
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// 从原始命令中提取设备地址
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byte deviceAddress = StringToByteArray(command.Substring(0, 2))[0];
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// 验证设备地址
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if (responseBytes[0] != deviceAddress)
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return false;
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// 验证功能码(响应中的功能码应与请求相同，若有异常则功能码最高位为1)
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byte requestFunctionCode = StringToByteArray(command.Substring(2, 2))[0];
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byte responseFunctionCode = responseBytes[1];
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// 检查是否为异常响应
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if ((responseFunctionCode & 0x80) != 0)
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{
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byte errorCode = responseBytes[2];
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Console.WriteLine($"Modbus异常响应 - 功能码: {requestFunctionCode}, 错误码: {errorCode}");
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return false;
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}
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// 验证功能码是否匹配
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if (responseFunctionCode != requestFunctionCode)
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return false;
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// 验证CRC校验
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ushort receivedCrc = (ushort)((responseBytes[responseBytes.Length - 2] << 8) | responseBytes[responseBytes.Length - 1]);
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ushort calculatedCrc = CalculateCRC(responseBytes, responseBytes.Length - 2);
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return receivedCrc == calculatedCrc;
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}
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// 计算Modbus RTU CRC校验
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private static ushort CalculateCRC(byte[] data, int length)
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{
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ushort crc = 0xFFFF;
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for (int i = 0; i < length; i++)
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{
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crc ^= data[i];
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for (int j = 0; j < 8; j++)
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{
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if ((crc & 0x0001) != 0)
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{
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crc >>= 1;
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crc ^= 0xA001;
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}
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else
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{
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crc >>= 1;
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}
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}
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}
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return crc;
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}
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// 将十六进制字符串转换为字节数组
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private static byte[] StringToByteArray(string hex)
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{
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int length = hex.Length;
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byte[] bytes = new byte[length / 2];
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for (int i = 0; i < length; i += 2)
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{
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bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
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}
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return bytes;
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}
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}
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