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4.13
Date Code 20171021
Instruction Manual
SEL-421 Relay
Front-Panel Operations
Front-Panel Operator Control Pushbuttons
The
IRIG LOCKED
target LED illuminates when the relay detects synchronization to
an external clock with less than 500 ns of jitter (Relay Word bit TIRIG is
asserted). See
Configuring Timekeeping on page 3.75 in the SEL-400 Series
Relays Instruction Manual
for complete details.
Front-Panel Operator Control Pushbuttons
The SEL-421 front panel features large operator control pushbuttons coupled
with amber annunciator LEDs for local control.
shows this region of
the relay front panel with factory-default configurable front-panel label text. The
SEL-421 provides either 8 or 12 pushbuttons depending on ordering option.
Factory-default programming associates specific relay functions with the eight
pushbuttons and LEDs, as listed in
. For a concise listing of the default
programming for the front-panel pushbuttons and LEDs, see
Figure 4.10
Operator Control Pushbuttons and LEDs (8 or 12 Pushbuttons)
Table 4.4
Operator Control Pushbuttons and LEDs—Factory Defaults
Label
Function
SPT ENABLED
Enable single-pole tripping
COMM SCHEME ENABLED
Enable communications scheme
ALT SETTINGS
Switch between setting group 1 and setting group 2
a
. The LED is
illuminated when group 1 is not the active setting group.
a
With factory settings, the
ALT SETTINGS
pushbutton must be pressed and held for three seconds
before the SEL-421 will change setting groups.
RELAY TEST MODE
Enter test mode
MANUAL CLOSE ENABLED
Enable manual closing
RECLOSE ENABLED
Enable automatic reclosing
AUX n
b
b
Available on 12-pushbutton models; n is the number of AUX buttons available depending on
ordering option.
Auxiliary
BREAKER CLOSED
c
c
Not available on models with auxiliary
TRIP/CLOSE
pushbuttons.
Close Circuit Breaker 1
BREAKER OPEN
Open Circuit Breaker 1
Operator
Control
Pushbutton
Annunciator LED
Summary of Contents for SEL-421-4
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