Alarm Hysteresis - CD Automation Revo TC 2ph User Manual

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14.3.2 Alarm Hysteresis

The purpose of the hysteresis is to prevent, when the measurement is near the thresholdand there are
disturbances on the measure, the alarm state changes continuously from ON to OFF and vice versa.
To do this it's possible to define a "safety margin" so that the alarm goes ON when the measure reaches a
specified value (A) but does not go OFF before the measure reaches another value (B) more closely to the
optimal condition.
Value (A) Is used as the threshold and value (B) as the threshold more or less hysteresis;
The following example will clarify the foregoing.
Considering that we want to set a Low alarm process that goes ON at least 300 ° C (value A) and returns to
OFF only when the measure has risen to 360 ° C (B value).
In this case the setting of the threshold is 300 (° C)
In questo caso il valore di soglia da impostare è 300 (°C) while the hysteresis have to be set equal to 60(°C).
note. The hysteresis value is expressed on the instrument in % of full scale.
14.3.3 Alarm Out
Ge era y the state f a a ar is ade visib e t the user a d ca a s pr duce physica acti s the
syste
The status indication of an alarm can be:
1) Visual indication (a 2ED the fr t f the i stru e t pa e )
2) S ftware i dicati (state f a b ea variab e the seria c u icati )
3) State f a physica 'ut ( r a y a re ay)
( te6
a) These three i dicati s are prese t b th i dividua y tha si u ta e us y
b) At" State f a physica 'ut " are ass ciated a s physica acti the syste
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