/// <summary> /// Initializes the request ADU and calculates the response length. /// </summary> public virtual void InitReqADU(byte devAddr, TransMode transMode) { if (ReqPDU == null) { return; } int pduLen = ReqPDU.Length; switch (transMode) { case TransMode.RTU: ReqADU = new byte[pduLen + 3]; ReqADU[0] = devAddr; Buffer.BlockCopy(ReqPDU, 0, ReqADU, 1, ReqPDU.Length); ushort crc = ModbusUtils.CRC16(ReqADU, 0, pduLen + 1); ReqADU[pduLen + 1] = (byte)(crc % 256); ReqADU[pduLen + 2] = (byte)(crc / 256); RespAduLen = RespPduLen + 3; break; case TransMode.ASCII: byte[] aduBuf = new byte[pduLen + 2]; aduBuf[0] = devAddr; Buffer.BlockCopy(ReqPDU, 0, aduBuf, 1, ReqPDU.Length); aduBuf[pduLen + 1] = ModbusUtils.LRC(aduBuf, 0, pduLen + 1); StringBuilder sbADU = new StringBuilder(); foreach (byte b in aduBuf) { sbADU.Append(b.ToString("X2")); } ReqADU = Encoding.ASCII.GetBytes(sbADU.ToString()); ReqStr = ModbusUtils.Colon + sbADU; RespAduLen = RespPduLen + 2; break; default: // TransModes.TCP ReqADU = new byte[pduLen + 7]; ReqADU[0] = 0; ReqADU[1] = 0; ReqADU[2] = 0; ReqADU[3] = 0; ReqADU[4] = (byte)((pduLen + 1) / 256); ReqADU[5] = (byte)((pduLen + 1) % 256); ReqADU[6] = devAddr; Buffer.BlockCopy(ReqPDU, 0, ReqADU, 7, ReqPDU.Length); RespAduLen = RespPduLen + 7; break; } }
/// <summary> /// Performs a request in the ASCII mode. /// </summary> protected bool AsciiRequest(DataUnit dataUnit) { bool result = false; // send request log.WriteLine(dataUnit.ReqDescr); Connection.WriteLine(dataUnit.ReqStr, out string logText); log.WriteLine(logText); // receive response string line = Connection.ReadLine(Timeout, out logText); log.WriteLine(logText); int lineLen = line == null ? 0 : line.Length; if (lineLen >= 3) { int aduLen = (lineLen - 1) / 2; if (aduLen == dataUnit.RespAduLen && lineLen % 2 == 1) { // receive response ADU byte[] aduBuf = new byte[aduLen]; bool parseOK = true; for (int i = 0, j = 1; i < aduLen && parseOK; i++, j += 2) { try { aduBuf[i] = byte.Parse(line.Substring(j, 2), NumberStyles.HexNumber); } catch { log.WriteLine(ModbusPhrases.IncorrectSymbol); parseOK = false; } } if (parseOK) { if (aduBuf[aduLen - 1] == ModbusUtils.LRC(aduBuf, 0, aduLen - 1)) { // decode response if (dataUnit.DecodeRespPDU(aduBuf, 1, aduLen - 2, out string errMsg)) { log.WriteLine(ModbusPhrases.OK); result = true; } else { log.WriteLine(errMsg + "!"); } } else { log.WriteLine(ModbusPhrases.LrcError); } } } else { log.WriteLine(ModbusPhrases.IncorrectAduLength); } } else { log.WriteLine(ModbusPhrases.CommErrorWithExclamation); } return(result); }