DAQmx read

[AndreaD]

Hi,

I'm trying to get familarized with the DAQmx data acquisition functions, hoping to gather data using Analog. In using the DAQmx Read, I'm encountering inputs of DBL, Wfm, and unscaled data. Instead of re-hashing something which is probably already available, can someone direct me to a document which would explain each data type and what they mean in terms of the analog signal input? I've tried to start taking data from each, and I can't seem to make sense in what I'm reading. 

Thanks,

Andrea

[tbob]

You have to choose the polymorphic instance of DAQmx Read to match the data that you expect to read.  If you click on the down arrow in the box just below the Read function, you can choose the data type.  If you have one DAQ channel, you choose Analog - Single Channel.  If reading just one point, you then choose Single Sample.  The data will be DBL.  If you want to read several samples, choose Multiple Samples and the data can either be a 1D array of DBL, or a Waveform (Wfm).  So its up to you to choose the type of data you expect to read.  This picture shows how to read a waveform from a single channel with multiple samples:  A waveform is simply a collection of DBL data values (like a 1D array of DBL), with extra information like T0 (initial starting time) and dt (time between each sample).