Demux a Signal in Labview after DAQ acquisition - Unbundle ???

[Loures]

Hello,

I am trying to demux a signal that has been digitally converted by the DAQ 6363. The bus signal (input analog signal) is formed with a  sequential sample that is related from its respective channel. Number of channels can dinamically change according to the experiment, as consequence, the number of columns from my output might need to follow it.

I would like in my output an array or variable that has the number of column as equal as the number of channels. I have seen in prevoius posts that the function "unbundle"  might do the job, but with a fixed number of columns.

Please, comments and suggestions are most than welcome

Best,

Joao S.

[Dennis_Knutson]

When you use the DAQmx Read set for nchan, you can return the data as a 1D waveform array where each element in the array represents a single channel. You can optionally return a 2D dbl array but this has no timing information. Please don't use the DAQ Assistant that returns dynamic data.

[Loures]

Ok, tks.

But, for example, if I do have a 1D array with 1000 samples (output of the DAQ assistent) and then I want to create a array with 4 columns where each column will have the following samples order

     column 1: samples 1, 4, 9 and so on...

     column 2: samples 2, 6, 10 and so on...

     column 3: samples 3, 7, 11 and so on...

     column 4: samples 4, 8, 12 and so on...

Would you have any idea to work it out?

Best

Joao S

[Dennis_Knutson]

Why would you want a 1D array? Are you taking a single sample per channel?

[Loures]

The output of the DAQ is a single discrete signal that I want to demux info up to 4 different columns.

[Dennis_Knutson]

A single discrete signal cannot be demuxed into different columns. A single discrete signal represents a single sample for a single channel. That is not the 1D array you were talking about. A DAQmx Read set for nchan 1samp returns a 1D array instead of a scalar and each element is a channel. Repeatedly smoking, you would build each acquisition (the 1D array) into a 2D array with s column for each channel.