Date Code 20010731 Control Logic 5-19
SEL-352-1, -2 Instruction Manual
Self-test failures, no power supplied to the relay, setting group changes in progress, and settings
being saved all extinguish the EN target LED for as long as the condition exists. Figure 5.8
shows the EN target LED logic.
Figure 5.8: EN Target LED Logic
PF Target LED
The pending failure (PF) target LED is illuminated and latched whenever a failure is pending,
based on various pending failure logic elements in the relay. The relay can detect a pending
failure for the following conditions:
Load current (LPF)
Trip resistor thermal condition (26TP)
Close resistor thermal condition (26CP)
Flashover (FOPF)
Current unbalance (UBPF)
Loss of Dielectric (LODPF)
If any one of the logic pending failure bits asserts, the PF target LED latches until the condition
goes away and either the Target Reset button is pushed or the TAR R command is issued to one
of the serial ports. Figure 5.9 shows the PF target LED logic.
Figure 5.9: PF Target LED Logic
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