Multi channel Wave Saving

[nicole99]

Hello,

Does anyone know and have done simultaneous saving of wave files for a number of channel coming from a DAQ card?
I have tried to use their "acquisition from muliple channel.vi" together with indexing of the tunnel that links the while loop but the playback sounds very high pitch.

Is there any way to make the "sav wave.vi" start for the various channel simultaneously?

Hope anyone can reply soon.

[Caroline Bright]

Hello,

You would want to use the Write Waveforms to File.vi. This vi creates a new file or appends to an existing file. Each record is an array of waveforms. This vi will allow you to save multiple waveforms at the same time. It can be found at All Functions -> Waveform -> Waveform File I/O.

Thanks,
Caroline
National Instruments

[X]

I have done the saving you speak of.

It really depends on how you are aquiring the data from the card. Sounds like you want to read 1 point at a time as a continous scan.

cycling between multiple channels via case struct in a while loop: 1 data point per channel while loop iteration: writing to ONLY 1 file

Open File before reading of channels occurs
In while loop create a case struct that cycles through each channel and writes the data point to the file. There should be one extra case at the end that checks if "Stop recording data" is pressed.
Things to consider:
Tab delimiting
last channel write to file case must have some type of return carriage
Data may appear as:

channel1[tab]channel2[tab]channel3....channeln
data1pt1[tab]data2pt1[tab]data3pt1 ...datanpt1
data1pt2[tab]data2pt2[tab]data3pt2 ...datanpt2
...
data1ptk[tab]data2ptk[tab]data3ptk ...datanptk

hope this points ya in some direction.
feel free to post more info on how you are reading the data - point by point, multiple arrays with n elements per scan(one per channel)
I may be able to help further if i know a little more. How about a sample VI from where ya stand?