Write & Read Binary files in a MultiChannel Con't DAQ

[lcz]

Hi there,

I'm using NI-DSA 4472 and the lockin startupkit(DAQmx version) but I need to modify the program so that I can record the data. The data type are DBL.  I tried using 'Write to binary file.vi' and  'Read from binary file.vi'. They are working for my test vi which is a single channel DAQ, but for MultiChannel I guess I need to create a header for the file. I found an example "Cont Acq&Graph Voltage-To File(Binary).vi" and "Graph Acquired Binary Data.vi" but it seems they deal with unscaled data I32. 

Any suggestions or right directions you can point me to for writing a header for Multichannel DAQ with DBL data type and convert the binary file to a txt file when the data are read later by another 'Read binary file' vi.

Thanks!

MAE at Rutgers

Chen

[knapkerd]

You could try using the TDMS write and read VIs instead.  They provide a place to enter the group and channel names.  Also, if you use a waveform data type with the TDMS write, the channel names are already included.  I havent used the TDMS format with DBLs, but it has worked well with waveforms and it is a fast and compact file type.

Hope this helps.

--Robert

[lcz]

Thanks, Robert.

The reason I want to write to binary file is because it's fast. I know nothing about TDMS file, but I'll take a look at it.   

Chen