ABB RELION REX640 Technical Manual page 1661

1MRS759142 C
REX640
Technical Manual
When the drop-off period is longer than the set Reset delay time, as described in
851, the input signal for the definite timer (here: timer input) is active, provided that
the current is above the set Start value. The input signal is inactive when the current
is below the set Start value and the set hysteresis region. The timer input rises when
a fault current is detected. The definite timer activates the START output and the
operate timer starts elapsing. The reset (drop-off) timer starts when the timer input
falls, that is, the fault disappears. When the reset (drop-off) timer elapses, the operate
timer is reset. Since this happens before another start occurs, the OPERATE output is
not activated.
GUID-0BD4948C-4D50-4400-804D-0A26D74B0AC9 V1 EN
Figure 852: Drop-off period is shorter than the set Reset delay time
When the drop-off period is shorter than the set Reset delay time, as described in
Figure 852, the input signal for the definite timer (here: timer input) is active, provided
that the current is above the set Start value. The input signal is inactive when the
current is below the set Start value and the set hysteresis region. The timer input rises
when a fault current is detected. The definite timer activates the START output and the
operate timer starts elapsing. The Reset (drop-off) timer starts when the timer input
falls, that is, the fault disappears. Another fault situation occurs before the reset (drop-
off) timer has elapsed. This causes the activation of the OPERATE output, since the
operate timer already has elapsed.
General function block features
Section 11
Figure
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