Handle sample format bitmap field in DAQmx scaler metadata

[adamreeve]

DAQmx scalers have a "sample format bitmap" field. The purpose of this isn't documented anywhere that I can find though, and it has always been set to zero in the DAQmx files I've seen. I've also tested writing TDMS files and setting this to non-zero values and then reading files with LabVIEW, but haven't been able to find any effect on the data values that LabVIEW reads.

At the moment npTDMS ignores this field, but I'm concerned there may be cases where this value is important to handle correctly.