ZENN
iO
AVANCE Y TECNOLOGÍA
vwww.zennio.com
25
25
In addition, it is important to keep in mind that the timer for periodic sendings is reset at the end of
the time unit immediately larger than the one used for defining the sending periods.
Example III
:
Exactly at midnight, the daily values corresponding to the previous day will always be calculated
and sent (concretely, those daily values that had been enabled under ETS). If a security sending
of the last daily values has been parameterized for every four hours, the hour counter will be
reset every midnight.
That’s why the first security sending of those values will happen at 4:00h
am, no matter if a parameter download (and the consequent time set) had taken place at 10:50h
pm.
Example IV
:
Exactly every Sunday at midnight (i.e., in the exact moment the day changes into Monday) the
weekly values corresponding to the previous week will always be calculated and sent
(concretely, those weekly values that had been enabled under ETS). If a security sending of the
last weekly values has been parameterized for every four days, the day counter will be reset with
this week change. This way, the next security re-sending will happen at the end of next
Thursday, that is, four day changes after the values were calculated. Considering that the
number of days in a week (7) is not a multiple of 4, this behaviour allows that the security
sendings take place the same days every week (in our case, when switching from Thursday to
Friday, apart from the ordinary sending at the end of Sunday), instead of spreading a certain
delay from week to week.
On the other hand, it must also be remarked that bus failures will also reset the timing for the
periodical sendings, which is anyway conditioned to the behaviour described in the two previous
examples.
Example V
:
A security sending is parameterized for every six hours and a parameter download takes place at
9:25h am, after which the internal clock is set to current time. When it’s 3:00h pm, the first
periodical sending happens. After that, at 5:15h pm, a bus failure takes place (or, alternatively,
the device is turned off for a few minutes). At 5:25h pm the voltage is recovered and the internal
clock is set again to current time (otherwise, it would assume that it is still 5:15h pm). Since the
voltage failure has caused a timing reset of the periodical sendings, the next security sending will
happen at 11:00h pm, even if the previous one had taken place at 3:00h pm.
