I am having an issue when reading a TDMS file and displaying it on a waveform chart in LabVIEW. My waveform chart will always display the time stamp with a negative offset of 18,000 samples.
To make that easy, let's say I am sampling at 1000 samples per second and I log my data to TDMS. When I read that TDMS and display my waveform chart data, the chart displays the data read from the TDMS 18 seconds earlier than the recorded wf_start_time stated within the TDMS. If my wf_start_time is 08:00:20.000 AM 12/02/2014, then my waveform chart displays a start time of 08:00:02.000 AM 12/02/2014. Likewise if I sample at 4000 samples per second, my start time is off by starting 4.5 seconds earlier.
I am setting my Xscale.offset = wf_start_time and it reads back correctly, but the start time on the waveform chart is still wrong.
Because I am dealing with larger TDMS files (500mb+), I sometimes decimate the data to view it due to memory issues. Here, this issue occurs again. If I decimate the data to only display 1 out of every 10 data points, that offset is further shifting by a factor of 10x; going from 18 seconds to 180 seconds.
Is this some kind of UTC/system clock time stamp discrepancy or something else?