4-14 B90 Low Impedance Bus Differential System GE Multilin4.3 FACEPLATE INTERFACE 4 HUMAN INTERFACES44.3.2 LED INDICATORSa) ENHANCED FACEPLATEThe enhanced front panel display provides five columns of LED indicators. The first column contains 14 status and eventcause LEDs, and the next four columns contain the 48 user-programmable LEDs.The RESET key is used to reset any latched LED indicator or target message, once the condition has been cleared (theselatched conditions can also be reset via the SETTINGS INPUT/OUTPUTS RESETTING menu). The RS232 port isintended for connection to a portable PC.The USER keys are not used in this unit.Figure 4–17: TYPICAL LED INDICATOR PANEL FOR ENHANCED FACEPLATEThe status indicators in the first column are described below.• IN SERVICE: This LED indicates that control power is applied, all monitored inputs, outputs, and internal systems areOK, and that the device has been programmed.• TROUBLE: This LED indicates that the relay has detected an internal problem.• TEST MODE: This LED indicates that the relay is in test mode.• TRIP: This LED indicates that the FlexLogic™ operand serving as a trip switch has operated. This indicator alwayslatches; as such, a reset command must be initiated to allow the latch to be reset.• ALARM: This LED indicates that the FlexLogic™ operand serving as an alarm switch has operated. This indicator isnever latched.• PICKUP: This LED indicates that an element is picked up. This indicator is never latched.The event cause indicators in the first column are described below.Events cause LEDs are turned on or off by protection elements that have their respective target setting selected as either“Enabled” or “Latched”. If a protection element target setting is “Enabled”, then the corresponding event cause LEDsremain on as long as operate operand associated with the element remains asserted. If a protection element target settingis “Latched”, then the corresponding event cause LEDs turn on when the operate operand associated with the element isasserted and remain on until the RESET button on the front panel is pressed after the operand is reset.All elements that are able to discriminate faulted phases can independently turn off or on the phase A, B or C LEDs. Thisincludes phase instantaneous overcurrent, phase undervoltage, etc. This means that the phase A, B, and C operate oper-ands for individual protection elements are ORed to turn on or off the phase A, B or C LEDs.• VOLTAGE: This LED indicates voltage was involved.• CURRENT: This LED indicates current was involved.• FREQUENCY: This LED indicates frequency was involved.• OTHER: This LED indicates a composite function was involved.• PHASE A: This LED indicates phase A was involved.• PHASE B: This LED indicates phase B was involved.• PHASE C: This LED indicates phase C was involved.842811A1.CDR
