gmt vs. labview daylight saving time XL

[Gérard]

I am manipulating XL sheets with time& dates. Everything works fine except that all XL times are in GMT (number of fractional days since 1900). No problem to jump to Mac 1904 reference, but a problem to get rid of the daylight saving time offset without changing my Windows setting. Is there a way to get dates and times in string readable format from my GMT number from the time of EXCEL? In other words, can I get the offset somewhere from windows to adjust the number of seconds since 1904 to eliminate this daylight offset? Not the offset of the current time, but well the offset of the past instant from my XL sheets.
I could do that via XL and activeX, but I suspect someone has a vi to do the trick.
I guess the time jumps for daylig
ht saving times lies somewhare in Windows.
Gérard

[JRA]

There is a VI called "Seconds to Date/Time." The output of this is "date time rec." If you wire this into an unbundle by name.vi, you can select the item "is DST." This will tell you whether or not Daylight Savings Time is being applied and you can configure your code accordingly. Hope this helps.

[Al_S]

It looks to me like the "is DST" output of Seconds to Date/Time always works on today's date, not a date/time record you pass to it. So, you can use it to tell if Daylight Savings Time is active now, but you can't use it to check if DST was active at a particular date and time, without changing the system time clock in the PC.

See the attached LV 6.1 VI.