DAQmx Read - 2D DBL or 1D Waveform?

[AlfredoT]

Hello,

I am new to using DAQmx vi's and need some clarification with identifying the proper DAQmx Read settings. I need to record the voltage output from two photodetectors (floating point sources) and at the same time plot them on the front panel of my vi. The following is a snapshot of the part of my code responsible for this:

 

I know that the setting for the DAQmx Read vi should be Analog -> Multiple Channels (for the two photodetectors) and think that the next choice should be Multiple Samples. However, what do 2D DBL and 1D Waveform mean?

Thank you.

[Cory_K]

They are just two different forms which you can receive your data.

1D waveform would be a 1D array of waveforms.

Each element in the array, would be a waveform from a certain channel.

The 2D array would be .... just that.

Example:

Voltage   Current  Amplitude

10              15           5

11              16           2

15              12           7

... etc

Either one will work for you.

You can pass either directly to a 'waveform graph'.

[Dennis_Knutson]

A dbl array is just that - nothing more than a bunch of numbers (i.e. the Y information). A waveform adds the timestamp when the acquisition was begun and the time between samples. If you need to recreate the waveform, you can use dbl array as long as you write the sample rate information to the file.