Thanks a lot for the links.
The main part of the code which is relevant is below. It runs using two tasks, one with a single analog output channel (analogOutputTask) and one with a single digital channel (digitalOutputTask). Both of these are running on their internal clocks and I am just changing the number of samples per run in the timing to account for the different signals queued.
// performing runs
for (int runCounter = 0; runCounter < numberOfRuns; runCounter++)
{
//setup first timing
timer.Reset();
analogOutputTask.Timing.SamplesPerChannel = analogSignals.Length;
digitalOutputTask.Timing.SamplesPerChannel = digitalSignals.Length;
timer.Start();
digitalWriter.WriteMultiSamplePort(false, digitalSignals);
analogWriter.WriteMultiSample(false, analogSignals);
timer.Stop();
bigQueueTimings[runCounter] = timer.ElapsedMilliseconds;
Console.WriteLine(bigQueueTimings[runCounter].ToString());
// run out those signals
digitalOutputTask.Start();
analogOutputTask.Start();
while(!analogOutputTask.IsDone || !digitalOutputTask.IsDone)
{
System.Threading.Thread.Sleep(2);
}
digitalOutputTask.Stop();
analogOutputTask.Stop();
//setup second timing
timer.Reset();
analogOutputTask.Timing.SamplesPerChannel = smallerAnalogSignals.Length;
digitalOutputTask.Timing.SamplesPerChannel = smallerDigitalSignals.Length;
timer.Start();
digitalWriter.WriteMultiSamplePort(false, smallerDigitalSignals);
analogWriter.WriteMultiSample(false, smallerAnalogSignals);
timer.Stop();
smallQueueTimings[runCounter] = timer.ElapsedMilliseconds;
Console.WriteLine(smallQueueTimings[runCounter].ToString());
// run out those signals
digitalOutputTask.Start();
analogOutputTask.Start();
while (!analogOutputTask.IsDone || !digitalOutputTask.IsDone)
{
System.Threading.Thread.Sleep(2);
}
digitalOutputTask.Stop();
analogOutputTask.Stop();
}
The signals are equivalent for both tasks (i.e. digitalSignals and analogSignals are the same length). If the two sets of signals are the same length for each task (i.e. digitalSignals and smallerDigitalSignals are the same length for the digital task) then there is no cumulative delay, but if they are different lengths then it takes about 3ms longer to queue every time I call WriteMultiSamplePort and WriteMultiSample. I also see no delay if I run this on a different daq (a 6343) or only running on a single module of the Cdaq (i.e. only analog output or only digital output).
Hopefully this helps.
Many thanks
