topic Re: Time on PDA UTC in LabVIEW

Time on PDA UTC

P E G — Thu, 10 Feb 2005 10:21:00 GMT

Problem with my palm Date management (Zire or T3)

It seems that if i write the "double value" (writen as a number, not translated in a string date format)
of current UTC date/time on my PDA it's 1h (3600 sec) older than my PC one's !!

And this even if the définition of Time UTC is, according to documentation, the same on PDA and on PC (i.e. Number of seconds since the 01/01/1904 12:00:00 a.m.

As someone an answer to give me ?

Re: Time on PDA UTC

tst — Thu, 10 Feb 2005 12:31:13 GMT

Just a guess, but this is probably due to time zone settings. Somewhere in the time zone calculations something appears to go wrong. Is the time zone in the palm the same as the one in the PC?

Re: Time on PDA UTC

P E G — Thu, 10 Feb 2005 13:12:17 GMT

Hi thank's for your interest,

In fact, it really seems to be a timezone problem ...

You can find here a VERY simple example that gives me the problem. Notice that both my PC and my Palm are set as Paris TimeZone.

If you compile and download the “testHUTC.vi” on a palm (Zire or T3), you’ll see strangely that time UTC doesn’t seem to e the same between Palm and PC (for us the time seems to be the Paris one and not the UTC one as said in the documentation of the “PDA Get Date Time in Seconds.vi” vi.

Am I write ?
If yes, how can I know the universal time on PDA ????

Re: Time on PDA UTC

tst — Thu, 10 Feb 2005 13:40:45 GMT

Unfortunately, I don't have a palm at all and my PocketPC is not available at the moment, so I can't check how this works. Is it possible that your computer has daylight savings time and your palm doesn't?
I believe the time starts from 01/01/1904 00:00 GMT, so try wiring a 0 or 3600 into a date\time display and see what comes out in the PC and in the palm and you'll be able to see if they're really off, or if the problem is with the PDA get date\time VI.

Re: Time on PDA UTC

P E G — Fri, 11 Feb 2005 07:52:02 GMT

I can give you the results of the VERY simple testHUTC.vi on both PC and Palm. the same vi is compile on PC and palm and the result is, if i run them at the same time:

PDA: 3190956154
PC : 3190952597

the difference is +3557 for the PALM. So 3600 at the time synchronisation difference of my PC and my palm (about one minute).

Notice, if you look at the diagram of the VERY simple vi, that at this point i never did any date format translation i just got the number of second since "01/01/1904 12:00:00 GMT" according to the documentation of the vi. I mean this number SHOULD be the number of second passed since "01/01/1904 12:00:00 GMT" on both machine.

Last, notice that in france daylight saving time is +1 but just in Summer ! So at the moment we haven't got this +1.

Re: Time on PDA UTC

tst — Fri, 11 Feb 2005 10:45:35 GMT

First, like you said - the VI takes the number of seconds that passed, so 3600 is an hour and not a minute.
This fits perfectly - either there is a bug (which, with the PDA module's track record, isn't impossible but it is less likely) or it's something with the settings. Try checking all your time zone settings and do what I suggested on my previous post (wire 0 into the conversion VI) - that way you'll be able to see which is off.

Re: Time on PDA UTC

P E G — Thu, 17 Feb 2005 11:04:49 GMT

Hi! Excuse me for this late answer i was out of this job for a while ...

Ok thank's for "hour" definition ;=)

I've done the tests you suggested ... and results are really bad for me ...

In fact in my application i have to save the date/time in a file in a GMT number of elapsed seconds since GMT zero (I can't assumle anything about the timezone of the palms)!

So to show the problem : look at the last vi i sent with this post you don't need to use it ! i give you the results here after used on PC and on PDA. You'll see that the number of seconds given by the Labview "Get date / time in second" is really time zone dependant on PDA! (according to the documentation it should not) so my problem become ... how can i know the timezone on my PDA !! to correct the number of seconds to the GMT one ?

On line is results given by PDA and PC simultaneously !
The second line is about 1'20" after the first

TimeZone PCNbElapsedSec PDANbElabsedSec PCS1SecTimeFormated PDAS1SecTimeFormated
Adelaide 3191482658 3191520414 01/01/1904 10:30:01 1/01/1904 0:00:01 AM
Paris 3191482749 3191486307 01/01/1904 01:00:01 1/01/1904 0:00:01 AM

Notice taht on PDA if you link zero to the date formater you get the current date so i linked 1 second !

Last: Are you part of NI support (if not) do you know how can i make them get interest in my problem ?

Re: Time on PDA UTC

P E G — Thu, 17 Feb 2005 12:59:00 GMT

Ouups !
about the previous post,: It's not 1'20" after the first try but about 50 seconds after the first try !

Re: Time on PDA UTC

tst — Thu, 17 Feb 2005 15:45:32 GMT

1. I'm not from NI. Like most people on this site I'm a regular user looking to learn and to help other people. NI employees have blue boxes next to their names while regular users have yellow or orange boxes (some people with an overactive imagination might call it gold). You can reward these users by giving them a lot of flattery and a lot of 5 star ratings. NI support personnel monitor these forums and offer support like all other users, but if you want to be sure they get your request, click on support on the top of any page in the site and send them an email requesting help. In general, I think it's preferable to start by using the search engine to try find if someone hasn't already answered your question and to get more data. If that doesn't help, use the forums (where you can find experienced users who dealt with all inds of situations) and if that doesn't help, email NI.

2. I don't have access to LV 7.1 at the moment, so I can't look at your code, but if I understand your description and table correctly, you're actually getting what you wanted - you wire 1 into the PDA VI and you get 00:00:01 - that's GMT. I never worked with a palm but I think OS 4 and above should have a timezone setting in its preference settings screen.

3. Finally, it is possible that there is a bug and that the VI on the PC and on the PDA are not acting the same - one outputs time in local time and the other in GMT. I just don't have the means to check at the moment and I don't think I'll have time for it soon. Try emailing NI and include a link to this page (just copy the url from your browser).

Re: Time on PDA UTC

P E G — Thu, 17 Feb 2005 17:37:14 GMT

Thank you very much to have shown interest in my request.
I'll try to mail this to NI, because i still don't have the time Zone independant number of seconds elapsed since 01/01/1904 00:00:00.
I've got a 5.2.8 OS and i've got the time zone setting (that's what i did to give you Adélaide results).
The final problem is that timezone difference is directly added to Number of seconds that's why when i format a "get time date in seconds vi" result to a date text formater the result is timezone dependant OK. But the number of seconds elapsed still now stay timezone dependant !

Very Sad Again ...

P E G — Wed, 23 Feb 2005 08:11:21 GMT

I've one more time followed the right procedure to try to find an answer to my question, Looking at forum, posting in forum, then mail support and .... except some exchanges with "tst" (thank's very much) no answer !!

My question seems very simple it's to get this in Labview code:
- How to get the real GMT NB OF SECONDS SINCE 01:01/1904 00:00:00 on my PDA (PALM) ?
- Or for example how can i know the current timzone Nb second difference with GMT on a my PDA ?

Please help for a trick !

Re: Very Sad Again ...

tst — Wed, 23 Feb 2005 08:38:37 GMT

I see this is still troubling you, so I'll make a suggestion.
I don't have the means at the moment to check this, but if the the number of seconds output by the Get Date\Time VI is timezone dependant, I suggest you let your user determine the time zone and save this in a config file.

Re: Very Sad Again ...

P E G — Wed, 23 Feb 2005 09:43:08 GMT

Your right ... i should do that ...

But yu know my palm application is a bit complex with many existing parameters in a recorded saved file, for Data aquisition with bluetooth peripherals, for recording parameters, for displaying parameters, for an exchange protocol, for some learning behaviour with (simple) user interface (for electrician, i mean they are not computer scientist ... some of them could even don't know anything about GMT time, or won't think about configuring it according to the real Palm configuration !). In the full software solution, we've got also information comming from a linux box with specific hardware that make recording session also (for electricity surveying), and at the end many log files are joined for a spécific Pc client software and for specific server processing to make data analysis ...

That's why i'd prefer this kind of information not to be depending on a user action.

If you wan't to have a look to our works go on www.watteco.com.

But again thank you very much for you interest and solution proposition, maybe i'll finally do what you suggect !

Re: Time on PDA UTC

P E G — Wed, 09 Mar 2005 11:14:43 GMT

Hi all,

Mr Tillet from French National support answered me and explained me that I should make my own system call on PDA, then I read a bit about this subject and discovered that I could make my stub dll with LabWindows CVI (at the moment I’ve no other C dev platform on my PC), and finally I went on palm reference API to find the way to get the TimeZone difference !

So it’s Ok my problem is solved,

Thanks for all.