private void StartDaq()
{
//Insert the range value into the table
if (CanSelectRange)
{
Database.InsertInfoCommand.Parameters.Add(new SQLiteParameter("Resolution", (int)Resolution));
Database.ExecuteCommand(Database.InsertInfoCommand);
CanSelectRange = false;
}
//Begin Daquisition
int packetSize = 16;
_dataPtr = MccService.ScaledWinBufAllocEx(32);
ScanOptions options = ScanOptions.SingleIo | ScanOptions.Continuous | ScanOptions.Background | ScanOptions.ScaleData;
if (SamplePeriod > 1000)
{
options |= ScanOptions.HighResRate;
}
if (DaqBoard.BoardName == "USB-1608G")
{
packetSize = 8;
}
if (DaqBoard.BoardName == "USB-1408FS")
{
MccService.WinBufFreeEx(_dataPtr);
_dataPtr = MccService.WinBufAllocEx(4);
packetSize = 2;
options = ScanOptions.SingleIo | ScanOptions.Continuous | ScanOptions.Background;
}
_daqBoard.AInScan(0, numChannels, 2 * packetSize, ref _sampleRate, Resolution, _dataPtr, options);
_isReading = true;
BeginChartUpdateAsync();
//Set buttons and status label to Running state
CanStart = false;
CanStop = true;
CanBrowse = false;
Status = "Running";
StatusBrush = Brushes.LimeGreen;
}
public override IObservable <Mat> Generate()
{
const int PacketSize = 256;
return(Observable.Create <Mat>((observer, cancellationToken) =>
{
return Task.Factory.StartNew(() =>
{
var range = Range;
var sampleRate = SampleRate;
var sampleCount = SampleCount;
var lowChannel = LowChannel;
var highChannel = HighChannel;
var board = new MccBoard(BoardNumber);
var channels = highChannel - lowChannel + 1;
var dataPoints = sampleCount * channels;
var bufferSize = PacketSize * (sampleCount * 2 / PacketSize + 1);
var bufferPoints = bufferSize * channels;
var buffer = new Mat(bufferSize, channels, Depth.S16, 1);
var options = ScanOptions.Continuous | ScanOptions.Background;
var dataAvailable = default(EventCallback);
using (var waitEvent = new AutoResetEvent(false))
using (var cancellation = cancellationToken.Register(() => waitEvent.Set()))
{
try
{
dataAvailable = delegate { waitEvent.Set(); };
var error = board.EnableEvent(EventType.OnDataAvailable, dataPoints, dataAvailable, IntPtr.Zero);
ThrowExceptionForErrorInfo(error);
var actualRate = sampleRate;
error = board.AInScan(lowChannel, highChannel, bufferPoints, ref actualRate, range, buffer.Data, options);
ThrowExceptionForErrorInfo(error);
if (actualRate != sampleRate)
{
throw new InvalidOperationException($"The specified sampling rate is not available. Suggested rate: {actualRate}");
}
var readIndex = 0;
while (!cancellationToken.IsCancellationRequested)
{
waitEvent.WaitOne();
error = board.GetStatus(out short status, out int count, out int index, FunctionType.AiFunction);
ThrowExceptionForErrorInfo(error);
if (index < 0)
{
continue;
}
index /= channels;
var overflowCount = 0;
var readCount = index - readIndex;
if (readCount < 0) // overflow
{
overflowCount = bufferSize - readIndex;
readCount = index + overflowCount;
}
while (readCount >= sampleCount)
{
readCount -= sampleCount;
var output = new Mat(channels, sampleCount, buffer.Depth, buffer.Channels);
if (overflowCount > 0)
{
overflowCount -= sampleCount;
if (overflowCount < 0) // wrap-around buffer, copy remainder
{
var overflowSamples = bufferSize - readIndex;
using (var outputOverflow = output.GetSubRect(new Rect(0, 0, overflowSamples, channels)))
using (var dataOverflow = buffer.GetSubRect(new Rect(0, readIndex, channels, overflowSamples)))
{
CV.Transpose(dataOverflow, outputOverflow);
}
readIndex = 0;
overflowSamples = sampleCount - overflowSamples;
using (var outputOverflow = output.GetSubRect(new Rect(sampleCount - overflowSamples, 0, overflowSamples, channels)))
using (var dataOverflow = buffer.GetSubRect(new Rect(0, readIndex, channels, overflowSamples)))
{
CV.Transpose(dataOverflow, outputOverflow);
}
observer.OnNext(output);
continue;
}
}
using (var data = buffer.GetSubRect(new Rect(0, readIndex, channels, sampleCount)))
{
CV.Transpose(data, output);
}
readIndex = (readIndex + sampleCount) % bufferSize;
observer.OnNext(output);
}
}
}
finally
{
board.StopBackground(FunctionType.AiFunction);
board.DisableEvent(EventType.OnDataAvailable);
GC.KeepAlive(dataAvailable);
}
}
},
cancellationToken,
TaskCreationOptions.LongRunning,
TaskScheduler.Default);
}));
}
