PXI-6289 Sample Rate

[codehawk]

Greetings:

I have a PXI-6289 Board in our PXIe-1095 chassis.

I am reading from a single Analog Input Channel and am attempting to understand the Sample Rate.

I am reading off a single Analog input channel so do not get an aggregate sample rate.

When I call the function (MeasAnalogVoltageChan-->See the code below.), the timing doesn't make any sense.

The code analogVoltTask.Timing.SampleClockRate returns only 1000 which is samples per second, but the stopwatch timer that included with my code

only shows ~7ms for the first one and ~18ms for the second.

If the sample rate was indeed 1000Samples/Sec than the second one should be at least 100ms with some overhead.

Can somebody help me understand the issue?

Thank you so much.

Here is the sample of code Visual Studio Code C#:

DaqCard = new Pxi6289();

Function calls:

var vref = DaqCard.MeasAnalogVoltageChan(Pxi6289.SignalName.VREF, 1, 1.0, 0.01); (1 Sample here)
var vref2 = DaqCard.MeasAnalogVoltageChan(Pxi6289.SignalName.VREF, 1000, 1.0, 0.01); (100 Samples here)

public double[] MeasAnalogVoltageChan(SignalName signalName, int numSamples, double max,double min)
{
     var name = GetChannelNameFromSignal(signalName);
     using var analogVoltTask = new Task();
     Stopwatch watch = new Stopwatch();

     //Starts the Timer
     watch.Start();

     // Create an Analog voltage input channel.
     AiTerminalConfig = AITerminalConfiguration.Rse;
     analogVoltTask.AIChannels.CreateVoltageChannel(name, "", AiTerminalConfig, min, max,AIVoltageUnits.Volts);

     // Read analog port data.
     var reader = new AnalogSingleChannelReader(analogVoltTask.Stream);

     analogVoltTask.Control(TaskAction.Verify);

     var sampleRate = analogVoltTask.Timing.SampleClockRate;

     //multi sample read
     var result = reader.BeginReadMultiSample(numSamples, null, null);
     var dataStream = reader.EndReadMultiSample(result);

     //dispose task once finished reading data
     if (analogVoltTask.IsDone)
     {
        //Stops the Timer
        watch.Stop();

        //Elapsed Time in milliseconds
        var elapsed = watch.ElapsedMilliseconds;
        TimeSpan timeSpan = watch.Elapsed;
        Console.WriteLine("Time: {0}h {1}m {2}s {3}ms", timeSpan.Hours,
        timeSpan.Minutes, timeSpan.Seconds, timeSpan.Milliseconds);
        Console.WriteLine("SampleRate: {0}Samples/Sec", sampleRate);
        analogVoltTask.Dispose();
     }

     //output the data
     return dataStream;
}