how to save the waveform chart information

[perumpadapu]

I am attaching a VI which recordes the power and wavelength from a ILX lightwave power meter. I had added  waveform chart  to the program to record the values of quatities with respect to time. Please kindly help me to read the quantities  on time with saving the values from initial time to final time. I I use shift registers with a built array in the while loop , will it retains the past values? 

[GerdW]

Hi perumpadapu,

I had added  waveform chart  to the program to record the values of quatities with respect to time.

Wrong. Charts don't display values with respect to time!

help me to read the quantities  on time with saving the values from initial time to final time.

You need to get timestamps too!

I I use shift registers with a built array in the while loop , will it retains the past values?

Yes, that's what they are made for!

When you need to ask about shift register I need to recommend you to take the FREE online beginner courses for LabVIEW provided by NI on their website!

[PeterFoerster]

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I had added  waveform chart  to the program to record the values of quatities with respect to time.

Wrong. Charts don't display values with respect to time!

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Hey Gerd,

I don't quite understand. If I wire a waveforme to a waveform chart it stores an processes data as waveform i.e. t0,dt and [y]. This, to me is in respect ot time.

If you meant, though, that it doesn't do that in his case, I very much agree with you.

As for the free tutorials:

3 Hour Introduction
6 Hour Introduction
LabVEW Basics
Self Paced training for students
Self Paced training beginner to advanced, SSP Required
LabVIEW Wiki on Training
Learning NI
Getting Started with NI Products

[GerdW]

Hi Peter,

ok, the chart displays waveforms according to their dt.

- What's the point in talking about charts when you already have a waveform available for saving? There's a ready-to-use function to save a waveform to a text file…

- The OP just reads scalar samples from the DAQ device and uses NO real timing in the DAQ loop. Where do you see any strict loop timing to have an accurate dt?

[PeterFoerster]

Thanks for clearing that up.

[perumpadapu]

thanks for the reply, but how can I stores the two measured quantities with respect to time other than waveform chart. If I use X-Y graph . The X will time and Y will be the quantity. So how can I wire the time data to X-Y graph.  Even if I am using the waveform chart  for recording the time dependent value of quantity how can I adjust the time interval. Please kindly reply

[GerdW]

Hi perumpadapu,

how can I stores the two measured quantities with respect to time

Get the timestamp and create a file with three columns: timestamp, first measurement value, 2nd measurement value…

how can I adjust the time interval.

- You already have a wait function in the loop.

- Maybe your DAQ device allows setting a fixed/accurate samplerate…