Timezone and DST

[BeanAnimal]

I know that timezones and DST can be frustrating to deal with.... And I know this has come up before, but I am frustrated with the way that P4 handles this.

It is Nov 1 - I have a tinezone mismatch warning on my P4. It happens 2x a year and bothers the snot out of me.

So it appears that it set my P4 clock back by exactly an hour already, even though DST ends on Nov 5
But what in the world does the 7 day setting do?

I assumed it adjusted the P4 clock gradually to remove 1 hour from real time.
So I guess I thought that starting 7 days out, the clock would slip by 8 minutes and 34 seconds per day difference, or some ~ 20 seconds per hour over the 7 days.
I don't see that happening though, just an hour difference, exactly between P4 and PC or Mobile.

In any case, twice a year my P4 time goes wonky and it frustrates me. Can anybody explain this? I would think that there has to be a cleaner solution, unless I am not understanding something. I did open a ticket to try to get an explanation.

 

[Reefer911]

If you figure it out please let us know. I didn’t even think about time changes and how they affect our dosing schedules. Although, in my case, I dont think it’s a big deal

 

[Reefer911]

I tried it but over 4 days. My time hasn’t changed yet.

 

[Vinny@GHLUSA]

The P4 Programming Guide explains how the clock and timezone works. See page 12.

The ProfiLux runs on two clocks; the display clock which shows the current time and the internal clock which controls the automatic processes such as timers and dosing times.

 

[BeanAnimal]

Hi Vinny, thanks for responding. But the manual is pretty vague.

Two clocks makes sense, but why is the display clock an hour off for a week or so twice a year (rhetorical), or at least the warning not suppressed? Also, I would think that there would be somewhere to see the internal vs display clock offset other than funky times on schedules tests like KH,

 

[Pod_01]

but why is the display clock an hour off for a week or so twice a year

Since on the topic of time, I always seem to have discrepancies between my device actual time and the P4 time in the app:

I can re-set it and after while it will drift again.
Anybody else gets the same feature?
Just curious….

 

[BeanAnimal]

MY P4 is setup to use NTP - but will sometimes be a minute or so off from the device. I assume that the RTC in the P4 has significant drift (most do) and without an NTP source will likely never match the device. I have no idea what the NTP update interval is. But - given time based dosing, etc. I would assume updating time can cause weird side effects.

 

[Reefer911]

What is NTP/RTC?

 

[BeanAnimal]

What is NTP/RTC?

NTP is Network Time Protocol
It is the protocol that devices use to get time from official time servers.

RTC is Real Time Clock
It is a time chip that attempts to keep real time on its own, be it in a computer or an alarm clock.

NTP can be used to automatically keep the RTC in sync with a real time source like a time server.

 

[Reefer911]

I’m not sure which setting my P4 is on but it will sometimes be a minute off. I’ve never seen it more than that. I just reset it. Maybe it’s a super slow drift and would eventually be further off.

Mobius used to be horrible, making any dosing schedule useless. Thankfully they fixed it

 

[KStatefan]

The programming guide is not clear.

"The first clock is a so-called real-time clock (RTC). It shows the actual ("our") time. This is also
the time normally seen on the display. In the event of a power failure, this clock runs on a
battery-backup."

What is "our" time?


Why did the time on my dashboard change?

 

[BeanAnimal]

@Vinny@GHLUSA was kind enough to fill in the gaps in a ticket.

The USA has wonky DST times. Europe (and likely other countries with DST on the metric system) all switch DST begining on the last Sunday in March and ending on the last Sunday in October.

The P4 has these dates hard coded. So if you have "Winter summer" time enabled on the P4, this is when it will switch.

Not idea, but it explains a lot.

DST can be a complex mess. I don't think the P4 implementation is clean, but I highly doubt that it will change.

Two simple solutions that I would urge them to look at (but will likely get no traction) would be to
either

A) allow the user to set the DST dates manually. However, this is as cumbersome as just dealing with it manually anyway.

or

B) they could setup an NTP server for the P4 with translation tables for the each timezone (disabling the hard coded DST and giving another option "NTP with DST for your local Timezone"). Yes there will be some oddballs that switch outside of their timezone, but I doubt many have P4s