Waveformgraph plot update time?

[busarider29]

Chipping away at this project.  I've got the task running and finally all my scaling correct and plotting a continuous trace to the waveform graph from the Ai virtual voltage channels.  Now.....how do I get the trace to update faster?  It appears that there is a considerable lag from when I adjust the voltage to the Ai channel versus the update rate of the plot on the Waveform Graph.  It appears very "slow".   I know it's something easy but I'm spinning my wheels trying to figure it out and find the problem. 

[GerdW]

General answer: Read your DAQmx input more often or read more samples at once…

For more precise answers you should attach your VI!

[busarider29]

I am coding in vb.net.  I posted here hoping to get a faster reply since the Labview forum is frequented more often.  My code is reading in a continuous loop with no delay time.  Is that the problem?

Public Sub dataAcquiring()
        reader = New AnalogMultiChannelReader(myTask.Stream)
        Dim data() As AnalogWaveform(Of Double) ' = reader.ReadWaveform(0)

        'While Scope switch is on, stream each Ai channel's data continuously to its respective WaveForm graph
        Do While swScopeOnOff.Value = True
            data = reader.ReadWaveform(sampleRate)
            wfgCh0.PlotWaveform(data(0))
            wfgCh1.PlotWaveform(data(1))
            wfgCh2.PlotWaveform(data(2))
            wfgCh3.PlotWaveform(data(3))
            wfgCh4.PlotWaveform(data(4))
            wfgCh5.PlotWaveform(data(5))
            wfgCh6.PlotWaveform(data(6))
            wfgCh7.PlotWaveform(data(7))
            wfgCh8.PlotWaveform(data(8))
            wfgCh9.PlotWaveform(data(9))
            wfgCh10.PlotWaveform(data(10))
            wfgCh11.PlotWaveform(data(11))
            wfgCh12.PlotWaveform(data(12))
            wfgCh13.PlotWaveform(data(13))
            wfgCh14.PlotWaveform(data(14))
            wfgCh15.PlotWaveform(data(15))
        Loop
        reader = Nothing
        data = Nothing
    End Sub

[Dennis_Knutson]

Unless you start coding in LabVIEW, you aren't going to get any help here.

[busarider29]

My timing configuration is as follows:

Signal source = device internal clock

Sample rate = 1000

Sample Clock Active Edge = Rising

Sample Quantity Mode = Continuous samples

Sample Per Channnel = 100

I've adjusted both the rate and samples per channel.  No change.

[GerdW]

Hi busarider,

I agree with Dennis: you should ask in a "vb.net" forum…

I didn't mention to change the sample rate: I suggested to read the DAQmx buffer more often…

As your loop spins without any additional delays (AFAIK) that shouldn't be a problem.

In LabVIEW I would suggest a consumer-producer-structure to decouple DAQmx handling from UI display!