/// <summary>
/// Reads process data from the selected location and device resources.
/// </summary>
/// <param name="pBlock"><see cref="T:CAS.Lib.CommonBus.ApplicationLayer.IBlockDescription" /> selecting the resource containing the data block to be read.</param>
/// <param name="pStation">Address of the remote station connected to the common field bus. –1 if not applicable.</param>
/// <param name="pData">The buffer <see cref="T:CAS.Lib.CommonBus.ApplicationLayer.IReadValue" /> containing the requested data.</param>
/// <param name="pRetries">Number of retries to get data.</param>
/// <returns>Result of the operation</returns>
/// <exception cref="System.ArgumentOutOfRangeException"></exception>
public AL_ReadData_Result ReadData(IBlockDescription pBlock, int pStation, out IReadValue pData, byte pRetries)
{
pData = null;
if (pBlock.dataType != 0)
{
TraceSource.TraceMessage(TraceEventType.Error, 149, $"Wrong dataType: {pBlock.dataType}; only data type = 0 is expected");
m_statistic.IncStRxInvalid();
}
if (!Connected)
{
TraceSource.TraceMessage(TraceEventType.Verbose, 165, $"ReadData failed because it is not connected; retries/limit={m_RetryCount}/{this.m_TextReaderProtocolParameters.MaxNumberOfRetries}.");
return(AL_ReadData_Result.ALRes_DisInd);
}
m_statistic.IncStTxFrameCounter();
IDataEntity _copy = Interlocked.Exchange <IDataEntity>(ref m_Fifo, m_Fifo);
bool _retResult = _copy != null;
m_statistic.RxDataBlock(_retResult);
if (!_retResult)
{
m_statistic.IncStRxNoResponseCounter();
TraceSource.TraceMessage(TraceEventType.Information, 186, $"ReadData failed; retries/limit={m_RetryCount}/{this.m_TextReaderProtocolParameters.MaxNumberOfRetries}.");
return(AL_ReadData_Result.ALRes_DatTransferErrr);
}
m_statistic.IncStRxFrameCounter();
pData = new ReadDataEntity(_copy, pBlock);
TraceSource.TraceMessage(TraceEventType.Verbose, 191, $"ReadData succeeded for [{pStation}/{pBlock.startAddress}]");
return(AL_ReadData_Result.ALRes_Success);
}
