Schweitzer Engineering Laboratories SEL-311C - Figure 5.17 Seal-In of Breaker Failure Occurrence for Message Display

5.34
SEL-311C Relay Instruction Manual Date Code 20060320
Trip and Target Logic
Front-Panel Target LEDs
DP3_1 = BREAKER FAILURE
DP3_0 =
(blank)
Figure 5.17 Seal-in of Breaker Failure Occurrence for Message Display
If a breaker failure trip has occurred, the momentary assertion of SV7T
(breaker failure trip) will cause SV8 in Figure 5.17 to seal in. Asserted SV8 in
turn asserts DP3, causing the message:
to display in the rotating default display.
This message can be removed from the display rotation by pushing the
{TARGET RESET} pushbutton (Relay Word bit TRGTR pulses to logical 1,
unlatching SV8 and in turn deasserting DP3). Thus, front-panel rotating
default displays can be easily reset along with the front-panel targets by
pushing the {TARGET RESET} pushbutton.
SV7T
Breaker Failure Trip
(= logical 1)
(= logical 0)
Target Reset
TRGTR
SV8
DP3 = SV8
DP3_1 = BREAKER FAILURE
DP3_0 = (blank)
BREAKER FAILURE