ABB RED615 Technical Manual page 799

1YHT530004D05 D
615 series
Technical Manual
When the drop-off period is longer than the set Reset delay time, as described in
Figure 424, 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.
A070420 V1 EN
Figure 425: 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 425, 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
793