common/Hardware/Interfaces/Ports/SerialPorts/BaseSerialPort.cs

using NLog;
using System;
using System.Collections.Generic;
using System.IO.Ports;
using System.Threading;
using Xylem.Common.CommonCore.Consts;
using Xylem.Common.CommonCore.ThreadWatcher;
using Xylem.Common.Hardware.Interfaces.Ports.PortCore;
using Xylem.Common.Hardware.Interfaces.Ports.PortCore.EventArguments;
using Xylem.Common.Utils.Logging;

namespace Xylem.Common.Hardware.Interfaces.Ports.SerialPorts
{
    /// <summary>
    /// All Ports must use BasePort as an base class 
    /// its support some wrapping event/function handling
    /// </summary>
    public abstract class BaseSerialPort : IPort, IDisposable
    {

        private ILogger _byteDataLogger;
        internal ILogger AsciiDataLogger;

        /// <inheritdoc />
        public virtual event EventHandler<BasePortDataEventArgs> OnRawRecordReceived;

        /// <summary>
        /// The port is not assigned.
        /// </summary>
        public const String PortNotAssigned = "NA";

        /// <inheritdoc />
        public virtual event EventHandler<BasePortDataEventArgs> OnRawRecordSendOut;

        //initially do not signal event
        private readonly AutoResetEvent _onSyncReceiveThread = new AutoResetEvent(false);
        private readonly Thread _receiveThread;
        private readonly CancellationTokenSource _receiveToken = new CancellationTokenSource();

        /// <summary>
        ///     Delay between bytes if receiving has started in milliseconds
        /// </summary>
        private const Int32 InterByteReadDelayMs = 50;

        /// <summary>
        ///     internal SerialPort class
        /// </summary>
        private readonly SerialPort _serialPort;


        /// <summary>
        ///     Activate raw record recording
        /// </summary>
        public Boolean RecordStreamingRawData = false;
        //public Boolean RecordStreamingRawData
        //{
        //    get => _recordStreamingRawData;
        //    set => _recordStreamingRawData = value;
        //}

        /// <summary>
        ///     date and time of incoming first date interrupt on serial IO to set the
        ///     PC time-stamp to the record
        /// </summary>
        private DateTimeOffset _receiveTimeStampPc;

        /// <summary>
        ///     Individual port settings depending on transmit protocol
        /// </summary>
        protected TransmitPortSettings PortSettingsForTransmitProtocol;

        /// <inheritdoc />
        public String GetPortName()
        {
            return _serialPort.PortName;
        }

        /// <summary>
        ///     store a identification of a port, this contains the Slot, Port, Protocol and Type
        /// e.g. "Slot:1, Port:COM4, Protocol:Request, Type:IrDA -"
        /// </summary>
        public String Ident;

        /// <summary>
        ///     ctor for SerialComPort with and full constructed <see cref="T:System.IO.Ports.SerialPort" /> properties
        /// </summary>
        /// <param name="ident">set port as unique</param>
        /// <param name="serialPort">Class for communication, all parameters for serial communication needs to be set</param>
        /// <param name="setting">Class for store all parameters for serial communication needs to be set came from transmit protocol</param>
        protected BaseSerialPort(String ident, SerialPort serialPort, TransmitPortSettings setting)
        {
            Ident = ident;

            //communication port settings
            _serialPort = serialPort;
            _serialPort.BaudRate = (Int32)setting.BaudRate;

            PortSettingsForTransmitProtocol = setting;

            //assign thread to loop
            _receiveThread = new Thread(ReadingThreadLoop) { Name = $"{Ident} Reading thread" };

            AsciiDataLogger = NLogHelper.CreateOrGetMultiLogger(Ident, "", "LedRawData", "TargetLedRawDataBase", "LedRawDataBase");
            _byteDataLogger = NLogHelper.CreateOrGetMultiLogger(Ident, "", "UartSerialPort", "COMBase", "BaseSerialPort");
        }


        public void RefreshLogger()
        {

            AsciiDataLogger = NLogHelper.CreateOrGetMultiLogger(Ident, "", "LedRawData", "TargetLedRawDataBase", "LedRawDataBase");
            _byteDataLogger = NLogHelper.CreateOrGetMultiLogger(Ident, "", "UartSerialPort", "COMBase", "BaseSerialPort");


        }



        /// <summary>
        /// received bytes in buffer of SerialComPort, calls base function
        /// </summary>
        /// <returns>number of bytes in Rx buffer</returns>
        protected Int32 BytesToRead()
        {
            try
            {
                return _serialPort.BytesToRead;
            }
            catch (Exception ex)
            {
                _byteDataLogger.Error(ex);
                return 0;

            }

        }

        /// <summary>
        /// read single byte from Rx buffer of SerialComPort, calls base function
        /// </summary>
        /// <returns></returns>
        protected Int32 ReadByte()
        {

            try
            {
                return _serialPort.ReadByte();
            }
            catch (Exception ex)
            {
                _byteDataLogger.Error(ex);
                return 0;

            }
        }

        /// <inheritdoc />
        public void PortWrite(Byte[] record)
        {
            try
            {
                SpecificPortWrite(record);
            }
            catch (Exception ex)
            {
                throw new SystemException($"{Ident} Communication error while sending data to port", ex);
            }
        }

        /// <inheritdoc />
        /// <summary>
        /// flush Rx and Tx buffer of SerialComPort, calls base functions
        /// </summary>
        public void Clear()
        {
            try
            {
                if (!_serialPort.IsOpen)
                {
                    return;
                }

                _serialPort.DiscardInBuffer();
                _serialPort.DiscardOutBuffer();
            }
            catch (Exception ex)
            {
                _byteDataLogger.Error(ex);

            }
        }

        /// <summary>
        ///     Dispose serial port
        /// </summary>
        /// <remarks date="2025-Mai-12..14" author="T.Wiedebusch">
        /// - Dispose procedure changed.
        /// </remarks>
        public void Dispose()
        {
            try
            {

                //remove registration for receive delegate
                _serialPort.DataReceived -= PhysicalDataReceived;

                //Cancel send and receive tokens
                _receiveToken.Cancel();

                //Run thread again to notice CancellationToken has changed
                _onSyncReceiveThread.Set();
                
                // dispose directly called from here to overcome glitches caused by USB to serial interface
                _serialPort.Dispose();

            }
            catch (Exception ex)
            {
                _byteDataLogger.Error(ex);
            }
        }


        /// <inheritdoc />
        public void Open()
        {
            try
            {
                //set receive interrupt threshold for immediate execution
                _serialPort.ReceivedBytesThreshold = 1;
                _serialPort.DataReceived += PhysicalDataReceived;

                //start reading thread, will be immediately put to waitSleepJoin in ReadingThreadLoop
                //to avoid side effects with RFID communication

                ThreadWatcher.Instance.Start(_receiveThread);

                if (!_serialPort.IsOpen)
                {
                    _serialPort.Open();
                    if (!_serialPort.IsOpen)
                    {
                        _byteDataLogger.Error($"{Ident} Port cannot be opened");
                        throw new ApplicationException($"{Ident} Port cannot be opened");
                    }
                    _byteDataLogger.Info($"{Ident} Port is opened");
                }
                else
                {
                    _byteDataLogger.Warn($"{Ident} Port was already opened");
                }
            }
            catch (Exception ex)
            {
                _byteDataLogger.Error($"{Ident} {ex.Message}");
                throw new ApplicationException($"{Ident} {ex.Message}");
            }
        }
        
        /// <summary>
        ///     Getting the base port
        /// </summary>
        protected SerialPort GetBaseComport()
        {
            return _serialPort;
        }

        /// <summary>
        ///     Fill FIFO with received data
        /// </summary>
        /// <remarks date="2018-Feb-16" author="T.Wiedebusch">
        /// - Initial
        /// </remarks>
        /// <remarks date="2018-Feb-21" author="T.Wiedebusch">
        /// - Time stamp added
        /// </remarks>
        /// <remarks date="2018-Dec-14" author="T.Wiedebusch">
        /// - Timeout moved from <see cref="ReadingThreadLoop"/> to PhysicalDataReceived to avoid
        ///   <see cref="TimeoutException"/> of serial port while waiting on first incoming
        ///   data.
        /// </remarks>
        /// <remarks date="2019-Dec-12" author="T.Wiedebusch">
        /// - Inter byte read delay used instead of response delay!!!
        /// </remarks>

        /// <param name="sender"></param>
        /// <param name="e"></param>
        public virtual void PhysicalDataReceived(Object sender, SerialDataReceivedEventArgs e)
        {
            if (!_receiveToken.IsCancellationRequested)
            {
                //remove event delegate to avoid repeated execution during one record
                _serialPort.DataReceived -= PhysicalDataReceived;

                //put the actual time stamp to this record being able to assign it correctly
                //even if the decoding is delayed. This time stamp will be used to do the first
                //synchronization at start and stop of the measurement. Therefore, the serial buffer
                //has to be flushed in advance to avoid wrong time stamp to "old" records
                _receiveTimeStampPc = DateTimeOffset.UtcNow;

                //start timeout for hanging read communication called inter byte delay
                _serialPort.ReadTimeout = InterByteReadDelayMs;
                // _serialPort.ReadTimeout = PortSettingsForTransmitProtocol.ResponseTimeoutMs;

                //wake up the reading threat from JoinWaitSleep
                _onSyncReceiveThread.Set();
            }
        }

        /// <summary>
        ///     <see cref="SyncMarkRecord" />
        /// </summary>
        private SyncMarkRecord _syncMarkRecord;

        /// <inheritdoc />
        public void SynchronizeReceiveBuffer(SyncMarkRecord syncMarkRecord)
        {
            try
            {

                //not in test bench situation only for temp logging
                if (syncMarkRecord == SyncMarkRecord.FlushBuffer)
                {
                    FlushBuffer();
                    return;
                }
                //DecodeEveryPackage is ongoing and SkipDecoding is requested  = do nothing
                if (_syncMarkRecord == SyncMarkRecord.DecodeEveryPackage &&
                    syncMarkRecord == SyncMarkRecord.SkipDecoding)
                {
                    return;
                }
                //deny intermediate record when a start or end record is requested
                if (syncMarkRecord == SyncMarkRecord.DecodeIntermediate &&
                    (_syncMarkRecord == SyncMarkRecord.SyncEnd ||
                     _syncMarkRecord == SyncMarkRecord.SyncStart))
                {
                    return;
                }
                //being able to detect the first incoming record after a sync is requested, the buffer is going to be flushed
                //if the measurement will be started or stopped
                if (syncMarkRecord == SyncMarkRecord.SyncEnd ||
                    syncMarkRecord == SyncMarkRecord.SyncStart ||
                    syncMarkRecord == SyncMarkRecord.DecodeIntermediate)
                {
                    FlushBuffer();
                }

                _byteDataLogger.Info($"{Ident} Mark next incoming record as {syncMarkRecord} (was {_syncMarkRecord})");
                _syncMarkRecord = syncMarkRecord;



            }
            catch (Exception ex)
            {
                _byteDataLogger.Error($"{Ident} {ex.Message}");
            }
        }

        private void FlushBuffer()
        {
            //check if flushing is allowed
            if (null != PortSettingsForTransmitProtocol.ReceiveBufferFlushThreshold)
            {
                //flush buffer above threshold to get an accurate actual record with next record coming in
                if (_serialPort.IsOpen && _serialPort.BytesToRead > PortSettingsForTransmitProtocol.ReceiveBufferFlushThreshold)
                {
                    _byteDataLogger.Warn($"{Ident} Flushed receive buffer({_serialPort.BytesToRead}Byte)");
                    _serialPort.DiscardInBuffer();
                }
            }
        }

        /// <summary>
        ///     Reading thread loop getting data from serial port
        /// </summary>
        /// <remarks date="2018-Feb-16" author="T.Wiedebusch">
        /// - Initial
        /// </remarks>
        /// <remarks date="2018-Mar-08" author="T.Wiedebusch">
        /// - Reading will be executed and repeated until buffer is empty or timeout
        /// </remarks>
        /// <remarks date="2018-Mar-09" author="T.Wiedebusch">
        /// - Receive byte protocol more dynamically on position of length information in record
        ///   and additional length,
        /// - decoding of data controlled by dataSyncMarker!= SyncMarkRecord.SkipDecoding to speed up recording
        /// </remarks>
        /// <remarks date="2018-Oct-23" author="T.Wiedebusch">
        /// - Directly invoked onRawRecord Received event,
        /// - Doubling of sync byte implemented
        /// </remarks>
        /// <remarks date="2018-Dec-14" author="T.Wiedebusch">
        /// - Timeout moved from ReadingThreadLoop to <see cref="PhysicalDataReceived"/> to avoid
        ///   <see cref="TimeoutException"/> of serial port while waiting on first incoming
        ///   data and flush receive buffer at timeout to force task to enter JoinWaitSleep state.
        /// </remarks>
        /// <remarks date="2019-Apr-11" author="T.Wiedebusch">
        /// - Hide data in logging for e.g. passwords
        /// </remarks>
        /// <remarks date="2019-Dec-03" author="T.Wiedebusch">
        /// - Raw record recording for missing sync-byte issues.
        /// </remarks>
        /// <remarks date="2019-Dec-04" author="T.Wiedebusch">
        /// - Try to recover raw record on missing SYNC byte by adding the SYNC upfront and sending
        ///   the record to the decoding thread which will detect if just the SYNC byte had been
        ///   missed, then the CRC will match and the record can be decoded.
        /// </remarks>
        /// <remarks date="2019-Dec-05" author="T.Wiedebusch">
        /// - Improved recovering of data sets at byte records with preceding SYNC byte:
        ///   - used payload length == 0 to skip decoding, it makes no sense to decode something where
        ///     the payload is empty,
        ///   - wait a certain time to complete incoming data.
        /// </remarks>
        /// <remarks date="2019-Dec-12" author="T.Wiedebusch">
        /// - Inter byte read delay used instead of response delay.
        /// </remarks>
        /// <remarks date="2019-Dec-14" author="T.Wiedebusch">
        /// - Flush buffer if received length is 0.
        /// </remarks>
        /// <remarks date="2022-Jul-15" author="T.Wiedebusch">
        /// - Flush buffer (DiscardInBuffer) removed as some bytes are missing from time to time.
        ///   The IrDA sniffer showed these on the communication line, but they are incompletely received.
        ///   Assuming the DiscardInBuffer may be delayed, so the incoming data will be scrapped.
        /// </remarks>
        /// <remarks date="2025-Mai-12..14" author="T.Wiedebusch">
        /// - Dispose procedure changed.
        /// </remarks>
        /// <remarks date="2026-Jan-06" author="T.Wiedebusch">
        /// - Replaced 'ReadLine' with 'ReadTo' using a string delimiter to support others than LF "\n".
        /// </remarks>
        private void ReadingThreadLoop()
        {
            //put the receive thread to JoinWaitSleep to avoid reading and logger output for timeout on 
            //RFID communication, because RFID will handle the physical receive by itself 
            //here the assignment of the _synReadingThreadEvent to the reading thread is being done
            _onSyncReceiveThread.WaitOne();

            try
            {
                while (!_receiveToken.IsCancellationRequested)
                {
                    try
                    {
                        //remind data marker for this Thread execution time slice
                        var dataSyncMarkThisRun = _syncMarkRecord;

                        //read line of ASCII indicated by syncByte == null
                        if (null == PortSettingsForTransmitProtocol.ProtSyncByte)
                        {
                            //exit is timeout from serialPort or received line
                            var rxStringRecord = _serialPort.ReadLine();

                            if (!string.IsNullOrEmpty(rxStringRecord))
                            {
                                //decode optional at synchronized data SyncStart, SyncEnd or DecodeIntermediate
                                //todo remove after air problem
                                if (SyncMarkRecord.SkipDecoding != dataSyncMarkThisRun)
                                {
                                    OnRawRecordReceived?.Invoke(this, new StringPortDataEventArgs(rxStringRecord,
                                        _receiveTimeStampPc, dataSyncMarkThisRun));
                                }

                                if (RecordStreamingRawData)
                                {
                                    AsciiDataLogger.Trace($"{rxStringRecord}");
                                }
                            }
                        }
                        //byte record with preceding SYNC byte
                        else
                        {
                            //normally decoding is required
                            dataSyncMarkThisRun = SyncMarkRecord.DecodeEveryPackage;

                            //this is the record for decoding
                            var rxByteRecord = new List<Byte>();

                            //this is the informational record for logging on undetected SYNC byte
                            var rxRawRecord = new List<Byte>();

                            //each byte protocol has to start with a syncByte, this has to be detected first
                            Byte rxByte;
                            do
                            {
                                rxByte = (Byte)_serialPort.ReadByte();
                                //record raw data stream for output on missing sync-byte to investigate this issue
                                rxRawRecord.Add(rxByte);
                            } while (_serialPort.BytesToRead > 0 && PortSettingsForTransmitProtocol.ProtSyncByte != rxByte);

                            // if syncByte has not been detected skip read loop and wait for next incoming record
                            if (PortSettingsForTransmitProtocol.ProtSyncByte == rxByte)
                            {
                                //save received SYNC byte
                                rxByteRecord.Add(rxByte);

                                //to assemble the length it has to be extracted first from the record at given index,
                                //the payload length index cannot be 0 because at this position is always the SYNC byte,
                                //the overall length includes the SYNC byte!
                                var length = PortSettingsForTransmitProtocol.ProtLengthIndex + 1;

                                //if the protLengthIndex is null the protAddLength equals the entire record length
                                if (null == PortSettingsForTransmitProtocol.ProtLengthIndex)
                                {
                                    length = PortSettingsForTransmitProtocol.ProtAddLength;
                                }

                                //read until length index to extract the length from the record
                                //the length index cannot be at position 0, because this is always the syncByte
                                do
                                {
                                    rxByte = (Byte)_serialPort.ReadByte();
                                    //read the next byte if doubled sync byte detected and required by transmit protocol settings
                                    if (PortSettingsForTransmitProtocol.DoubleSyncByte)
                                    {
                                        if (rxByte.Equals(PortSettingsForTransmitProtocol.ProtSyncByte) &&
                                            rxByteRecord[rxByteRecord.Count - 1]
                                                .Equals(PortSettingsForTransmitProtocol.ProtSyncByte))
                                        {
                                            //skips this byte and read the next one
                                            rxByte = (Byte)_serialPort.ReadByte();
                                        }
                                    }

                                    //add byte to receive result buffer
                                    rxByteRecord.Add(rxByte);

                                    //capture the length at given index and readjust the record length
                                    if (null != PortSettingsForTransmitProtocol.ProtLengthIndex
                                        && rxByteRecord.Count - 1 == PortSettingsForTransmitProtocol.ProtLengthIndex)
                                    {
                                        //if the received length indicates empty payload, then nothing is to decode
                                        if (rxByte == 0)
                                        {
                                            //exit this loop
                                            dataSyncMarkThisRun = SyncMarkRecord.SkipDecoding;
                                            FlushBuffer();
                                        }
                                        else
                                        {
                                            //build the new length to continue this receive loop
                                            length = (UInt16)(PortSettingsForTransmitProtocol.ProtAddLength + rxByte);
                                        }
                                    }

                                    //wait a certain time to let the data stream coming in
                                    if (length - rxByteRecord.Count - 1 > _serialPort.BytesToRead)
                                    {
                                        Thread.Sleep(2);
                                    }

                                } while (rxByteRecord.Count < length && dataSyncMarkThisRun != SyncMarkRecord.SkipDecoding);

                                //all data received or skip decoding marked, skip decoding will clear the response timeout
                                //these protocols have always to be decoded because the base is a request protocol
                                OnRawRecordReceived?.Invoke(this, new ListBytePortDataEventArgs(rxByteRecord,
                                    _receiveTimeStampPc, dataSyncMarkThisRun));
                            }
                            else
                            {
                                //output actual byte and recorded raw data stream to investigate missed sync-byte
                                _byteDataLogger.Warn($"{Ident} Response SYNC Byte missing. Raw Byte Received: " +
                                                     $"{BitConverter.ToString(rxRawRecord.ToArray())}");
                            }
                        }
                    }
                    catch (ThreadAbortException)
                    {
                        _byteDataLogger.Info($"{Ident} Thread abort exception fired!");
                    }
                    catch (TimeoutException)
                    {
                        //ATTENTION: This "_serialPort.DiscardInBuffer()" caused a lot of trouble as it flushes a few incoming
                        //bytes and therefore destroys the already started data stream. Here it had been left in to indicate
                        //this critical issue!
                        /*-------------------------------DO NOT ACTIVATE-----------------------------------------------------*/
                        //flush receive buffer at timeout to force task to enter JoinWaitSleep state in finally
                        //if (_serialPort.IsOpen)
                        //{
                        //    _serialPort.DiscardInBuffer();
                        //}
                        /*---------------------------------------------------------------------------------------------------*/

                        _byteDataLogger.Trace($"{Ident} Read timeout({InterByteReadDelayMs}ms)");
                        //_byteDataLogger.Trace($"{Ident} Read timeout({PortSettingsForTransmitProtocol.ResponseTimeoutMs}ms)");

                    }
                    catch (Exception ex)
                    {
                        if (_receiveThread.ThreadState == ThreadState.Aborted
                            || _receiveThread.ThreadState == ThreadState.AbortRequested)
                        {
                            _byteDataLogger.Warn(ex, $"{Ident} ThreadState is Aborted or AbortRequested but an " +
                                                     "error occurred while reading records from serial port");
                        }
                        else
                        {
                            _byteDataLogger.Error(ex, $"{Ident} Error while reading records from serial port");
                        }
                    }
                    finally
                    {
                        if (_serialPort.IsOpen && !_receiveToken.IsCancellationRequested)
                        {
                            //it makes no sense to put the thread to sleep if there is something to read
                            if (0 == _serialPort.BytesToRead)
                            {
                                //restore event delegate to activate handle for incoming records
                                _serialPort.DataReceived += PhysicalDataReceived;

                                //put this thread (receive thread) to JainWaitSleep
                                _onSyncReceiveThread.WaitOne();
                            }
                        }
                    }
                } //while (!_tokenReadData.IsCancellationRequested)
            } // over hole reading thread loop 
            catch (ThreadAbortException)
            {
                _byteDataLogger.Info($"{Ident} Thread abort exception fired!");
            }
            catch (Exception ex)
            {
                _byteDataLogger.Error($"{Ident} {ex.Message}");
            }
            //finally
            //{
            //    //var retries = 5;
            //    //while (_serialPort != null && _serialPort.IsOpen && retries-- > 0)
            //    //{
            //    //    _serialPort.Close();
            //    //    if (_serialPort.IsOpen)
            //    //    {
            //    //        _byteDataLogger.Info($"{Ident} Port closing delay!");
            //    //        Thread.Sleep(500);
            //    //    }
            //    //}
            //    //if (_serialPort != null && _serialPort.IsOpen)
            //    //    _byteDataLogger.Info($"{Ident} Port unable to close");
            //    //else
            //    //    _byteDataLogger.Info($"{Ident} Port is closed");
            //}
        }

        /// <inheritdoc />
        public Boolean IsOpen()
        {
            return _serialPort != null && _serialPort.IsOpen;
        }

        /// <summary>
        ///     Serial port specific write routine
        /// </summary>
        /// <param name="txBuffer"></param>
        /// <remarks date="2019-Apr-11" author="T.Wiedebusch">
        /// - Hide data in logging for e.g. passwords
        /// </remarks>
        protected virtual void SpecificPortWrite(Byte[] txBuffer)
        {
            PhysicalWrite(txBuffer);
        }

        /// <summary>
        ///     Physically sending to the serial port
        /// </summary>
        /// <remarks date="2017" author="R.Drabesch">
        /// - Initial
        /// </remarks>
        /// <remarks date="2018-Oct-23" author="T.Wiedebusch">
        /// - Doubling of sync byte in protocol behind sync byte itself implemented
        /// </remarks>
        /// <remarks date="2022-Feb-25" author="T.Wiedebusch, R.Drabesch">
        /// - Flush buffer as MOXA sometimes takes two messages and combines these to one!
        ///   As the Genesis needs a separated wake-up message with a following delay before the
        ///   real payload message, this causes a lot of trouble. 
        /// </remarks>
        protected void PhysicalWrite(Byte[] txBuffer)
        {
            try
            {
                //don't double the sync byte itself
                var txByteList = new List<Byte> { txBuffer[0] };
                for (var byteCtr = 1; byteCtr < txBuffer.Length; byteCtr++)
                {
                    txByteList.Add(txBuffer[byteCtr]);

                    //write the doubled sync byte again if required by transmit protocol settings
                    if (PortSettingsForTransmitProtocol.DoubleSyncByte)
                    {
                        if (txBuffer[byteCtr].Equals(PortSettingsForTransmitProtocol.ProtSyncByte))
                        {
                            txByteList.Add(txBuffer[byteCtr]);
                        }
                    }
                }

                _serialPort.Write(txByteList.ToArray(), 0, txByteList.Count);

                // flush the buffer for MOXA, to avoid two subsequent communications assembled to one communication!
                _serialPort.BaseStream.Flush();

                OnRawRecordSendOut?.Invoke(this, new ListBytePortDataEventArgs(txByteList, DateTimeOffset.UtcNow));
            }
            catch (Exception ex)
            {
                _byteDataLogger.Error($"{Ident} {ex.Message}");
            }
        }
    }
}