4 HUMAN INTERFACES
a) LED PANEL 1
This panel provides several LED indicators, several keys, and a communications port. The RESET key is used to reset any
latched LED indicator or target message, once the condition has been cleared (these latched conditions can also be reset
RS232 port is intended for connection to a portable PC.
IN SERVICE: Indicates that control power is applied; all monitored inputs/outputs and internal systems are OK; the
relay has been programmed.
TROUBLE: Indicates that the relay has detected an internal problem.
TEST MODE: Indicates that the relay is in test mode.
TRIP: Indicates that the selected FlexLogic™ operand serving as a Trip switch has operated. This indicator always
latches; the RESET command must be initiated to allow the latch to be reset.
ALARM: Indicates that the selected FlexLogic™ operand serving as an Alarm switch has operated. This indicator is
PICKUP: Indicates that an element is picked up. This indicator is never latched.
EVENT CAUSE INDICATORS:
These indicate the input type that was involved in a condition detected by an element that is operated or has a latched flag
waiting to be reset.
VOLTAGE: Indicates voltage was involved.
CURRENT: Indicates current was involved.
FREQUENCY: Indicates frequency was involved.
OTHER: Indicates a composite function was involved.
PHASE A: Indicates Phase A was involved.
PHASE B: Indicates Phase B was involved.
PHASE C: Indicates Phase C was involved.
NEUTRAL/GROUND: Indicates neutral or ground was involved.
menu). The USER keys are used by the Breaker Control feature. The
Figure 4–4: LED PANEL 1
L90 Line Differential Relay
4.2 FACEPLATE INTERFACE
4.2.2 LED INDICATORS