LSI LASTEM E-Log, User Manual

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LSI LASTEM E-Log – User’s manual
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
The length of alarm or not alarm period.
The alarm condition is detected when, within the specified period that starts from the first
precipitation event, the maximum precipitation quantity is exceeded; from alarm condition
beginning or at the end of the first period, are managed new periods and for each of them the rain
totalization starts from zero; for each new period, if the rain fall quantity returns below the specified
minimum value, the system returns in no alarm condition.
5.5.5. Threshold value compare
The logic detects value overflow or underflow by one or more measures (both univocally and
simultaneously). To the threshold values can be applied a further hysteresis value; this can avoid
continuous alarm state changes in case the measure value moves nearly around the threshold value.
The comparison logics are the following:

Greater than : alarm in case the measure value if greater than the threshold value added to
the hysteresis; return to no alarm condition when the measure value in lesser than the
threshold value minus the hysteresis; i.e. threshold value=4.0 and hysteresis=0.2 (alarm in
shaded area):

Lesser than : alarm in case the measure value is lesser than the threshold value minus the
hysteresis; return to no alarm condition when the measure value is greater than the threshold
value added to the hysteresis; i.e. threshold value=4.0 and hysteresis=0.2 (alarm in shaded
areas):