How can I read a binary file stream with many data type, as with AcqKnowledge physio binary data file?

Question

I would like to read in and write physiological data files which were saved by BioPac�s AcqKnowledge 3.8.1 software, in conjunction with their MP150 acquisition system. To start with, I�d like to write a converter from different physiodata file format into the AcqKnowledge binary file format for version 3.5 � 3.7 (including 3.7.3). It will allow us to read different file format into an analysis package which can only read in file written by AcqKnowledge version 3.5 � 3.7 (including 3.7.3).
I attempted to write a reader following the Application Note AS156 entitled �AcqKnowledge File Format for PC with Windows� (see http://biopac.com/AppNotes/ app156Fi
leFormat/FileFormat.htm ). Note the link for the Mac File format is very instructive too - it is presented in a different style and might make sense to some people with C library like look (http://biopac.com/AppNotes/ app155macffmt/macff.htm).
I guess the problem I had was that I could not manage to read all the different byte data stream with File.vi. This is easy in C but I did not get very far in LabView 7.0. Also, I was a little unsure which LabView data types correspond to int, char , short, long, double, byte, RGB and Rect. And, since it is for PC I am also assuming the data to be written as �little endian� integer, and thus I also used byte swap vi.
Two samples *.acq binary files are attach to this post to the list. Demo.acq is for version 3.7-3.7.2, while SCR_EKGtest1b.acq was recorded and saved with AcqKnowledge 3.8.1, which version number is 41.
I would be grateful if you someone could explain how to handle such binary file stream with LabView and send an example to i
llustrate it.
Many thanks in advance for your help.
Donat-Pierre
Attachments:
Demo.acq ‏248 KB
SCR_EKG_test1b.acq ‏97 KB

Answer 1

The reading of double is also straight forward : just use a dble float wired to the type cast node, after inverting the string (indian conversion).
See the attached example.
The measure of skin thickness is based on OCT (optical coherent tomography = interferometry) : an optical fiber system send and received light emitted to/back from the skin at a few centimeter distance. A profile of skin structure is then computed from the optical signal.
CC
Chilly Charly    (aka CC)
         E-List Master - Kudos glutton - Press the yellow button on the left...        
Attachments:
Read_AK_time_info.vi.zip ‏9 KB