Binary file format

[Antti Ryhänen]

Hello!

What is the binary file format for files created by Labview's example High
Speed Data Logger? The header information comes first, but how is the actual
logged data written in the file? I have logged two channels.
Thanks in advance for advice.

Best regards,
Antti Ryhänen

[Dennis_Knutson]

It's I16 - the VI that does the saving is called Write File+ [I16].vi and this information is also part of the High Speed Datalogger documentation. If you have context help turned on, just move your mouse cursor over the VI's icon to display this. To read files created by the VI, use High Speed Data Reader.vi.

[BLOODLEE1]

Then how is this integer been casted into float point value?

[mikeporter]

Check out the diagram of the "High Speed Data Reader.vi", it's not cast, it's simply scaled.

Mike...

[BLOODLEE1]

I'm working on a programing using VC or VB to read the binary file generated by high speed data logger. I'd like to know how they scale the int16s into reals:
divide by # bits of A/D, multiply by range of input, multiply by EU conversion, add offset
Is that it? Is the input setting should be obtained from group channel setting recorded in the file header?
One more question how is the data arranged in rows or columns if I have multichannel inputs?

Thanks

[mikeporter]

The LV code first converts the I16s to U16s and casts it as single-precision floats. It them multiplies the result by a scaling factor that's stored in the data header and adds an offset that's found in the same place.

Mike...