Hi Matt87,
Reading data as I16 will return the unscaled, uncalibrated result of the 16-bit ADC.
If you want to write your own binary files, you'll want to include the device scaling coefficients--for X Series this is a 3rd order polynomial.
Here are a pair of examples that show how to write to a binary file and read the data back. In this example scaling coefficients are stored in the header of the file:
Continuous Acquire and Graph Voltage to File (Binary)
Graph Acquired Binary Data
Having said this, I would recommend that you look into the integrated TDMS logging feature that was introduced in DAQmx 9.0. The result is a binary .tdms file which is of a standard format that can be opened in LabVIEW or in several other programs with the correct plugin. See the following examples for how to use the feature:
Continuously Read Data and Log to TDMS File
Continuously Log Data to a TDMS File
The second example does not require you to read the data into LabVIEW memory and will utilize minimal CPU. The first example lets you see the data as it is being acquired.
Best Regards,
John Passiak