Windows MAX and IRIG

[faustina]

The timestamp I get in MAX using my 6682 differs from the indicator on my IRIG-B generator.  I understanding about displaying the UTC in LabVIEW http://digital.ni.com/public.nsf/allkb/3B5A19E2C4966D688625752E006C7C65, but my data must be timestamped with UTC independent of time zone or in/out of daylight savings.  Can this only be done by setting the Windows system time using LabVIEW and the kernal32.dll? https://decibel.ni.com/content/docs/DOC-25393  This could be a problem since neither I (a developer) or my users can change Windows system time.  We do not have sys admin priviledges.

[faustina]

My sys admin has modified Windows so I am able to change the system time using kernal32.dll.  However, MAX test panel is still showing incorrect time according to my IRIG generator.  I've checked the GMT and my IRIG generator is displaying the correct UTC.

[lcgse88]

Hi Faustina,

what is the diference of time between the two timestamps? From where did you take the IRIG-B generator?. I just found some information about this, please check it: 

http://digital.ni.com/public.nsf/allkb/C5BBF6AC7036CDAA8625733000668351?OpenDocument

[faustina]

exactly 1 hour.  I'm think daylight savings time is playing into this but I'm not sure how.  IRIG is based on GMT/UTC which doesn't have daylight savings time.  The IRIG time I receive from the card must be recorded to the data file as GMT/UTC.

[Sam_Sharp]

What are you actually doing with the data? All of the functions that convert a LabVIEW timestamp to a string / display support returning the data in UTC and the timestamp itself is timezone independent (it's the number of seconds since 1904).

Here's an example:

[faustina]

I am not displaying the time.  After getting the time using niSync Get Time VI, I write it to a TDMS file.  MAX, debug probes, and the TDMS file show the time as being 1 hour off from the IRIG generator.

[Sam_Sharp]

Which one is showing the correct time for your timezone? To be honest, I have no idea what an IRIG generator is - but it seems to be something for generating the current time?

MAX, debug probes and TDMS files will store the time in UTC, but display the time in your local timezone, as configured on your computer. If you want to change how they are displayed, you need to change the timezone, not the time on your computer to be UTC (coordinated universal time).

[faustina]

I have no trouble reading the timestamp from niSync Get Time.vi and displaying as UTC in LabVIEW.  How do I insure that the timestamp is saved in the TDMS file as UTC so that when DIAdem reads the file it is displayed as UTC?