5-18 Control Logic Date Code 20010731
SEL-352-1, -2 Instruction Manual
LED TARGETING LOGIC
The target LEDs on the front panel illuminate based on various relay conditions. Under normal
operating conditions, the EN LED should be lit. Whenever another LED is illuminated, it
indicates that the relay has detected a particular condition since the last time the Target Reset
button was pushed, the TAR R command was issued, or power was cycled. View these targets
remotely by issuing the TAR n command to one of the serial ports, where n is a number
representing the row of the Relay Word to be displayed. Row 0 and Row 1 of the Relay Word
represent the 16 LEDs.
Front-panel targets are processed every 1/8 cycle and illuminate for the conditions shown in
Table 5.7. All target LEDs latch except EN, 52A, and MOD. TRIP and CLOSE will reset one
another. Targets are reset when power is cycled. Refer to Figure 5.8 through Figure 5.20 for
logic diagrams for each target LED.
Table 5.7: Target LED Illumination Conditions
Target LED Conditions for Illumination Latched
Row 0
(top row)
EN Normal Operation No
PF Breaker Pending Failure Detected Yes
86BFT Lockout Relay Trip Yes
86RS Lockout Relay Reset Yes
TRIP Breaker Trip Received Yes*
CLOSE Breaker Close Received Yes*
52A 52A Status Input Assertion No
MOD MOD Status Input Assertion No
Row 1
(bottom row)
A A-Phase Breaker Failure Yes
B B-Phase Breaker Failure Yes
C C-Phase Breaker Failure Yes
FAULT Fault Current Protection Operated Yes
LOAD Load Current Protection Operated Yes
UBAL Current Unbalance Protection Operated Yes
FLASH Flashover Protection Operated Yes
THERM Thermal Failure Protection Operated Yes
*TRIP and CLOSE Target LEDs reset one another.
EN Target LED
The enable (EN) target LED is illuminated for all normal operating conditions. Any condition
that temporarily or permanently disables the relay protection and control capabilities
extinguishes the EN target LED.
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