D122.A
4 Manual
Page 16
4.3.2 Hysterese and time delay setting
Hysterese
A hysteretic curve prevents an
unwanted fast switching of the
alarm outputs.
The switching behavior of the low
alarm (min) shows figure 6. The
switching behavior of the high
alarm (max) shows figure 7.
on
off
alarm monitoring lower limit
measured value
lower limit
Figure 6: Hysteric curve low alarm
upper limit
hysteresis at upper limit
on
off
alarm monitoring upper limit
measured value
Figure 7: Hysteric curve high alarm
Time delay
The span of time ‘t
e
’ is the differ-
ence between the first exceeding
of the measurement above the
upper limit and the switching of
the high alarm (For the low alarm
exists an analogous ‘t
e
’).
on
off
time
moment of first exceeding
time delay t
measured value
alarm monitoring upper limit
time
upper limit
e
Figure 8: Time delay max respectively min
Note
If the measured current falls below the high limit during ‘t
e
’, the t
e
-
timer resets.
