Accuracy Of T; Accuracy Of The Timer (Weekly/Yearly Timer); Backup Of The Real-Time Clock - Siemens Logo! Manual

Accuracy of T

Because of slight tolerances in the characteristics of elec-
tronic components, the set time T may deviate. The LOGO!
has a maximum tolerance of " 0.02 %.
When 0.02 % of the time T is smaller than 0.02 seconds,
the maximum deviation is 0.02 seconds.
Example:
The maximum tolerance per hour (3600 seconds) is
" 0.02 %, which is proportional to " 0.72 seconds.
The maximum toloerance per minute (60 seconds) is
" 0.02 seconds.

Accuracy of the timer (weekly/yearly timer)

To prevent timing inaccuracy of the real-time clock in C ver-
sions caused by this deviation, the timer value is continu-
ously compared with a high-precision timebase and cor-
rected. The resultant maximum timing inaccuracy is $5
s/day.

4.3.3 Backup of the real-time clock

Because the internal real-time clock of a LOGO! is backed
up, it continues operation after a power failure. The ambi-
ent temperature influences the backup time. At an ambient
temperature of 25°C , the typical backup time is 80 hours.
If there is a power outage of a LOGO! for more than 80
hours, the internal clock responds, dependent on the equip-
ment series, as shown below:
LOGO! Manual
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LOGO! functions
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