U.5.6
SEL-421/SEL-421-1 Relay
User’s Guide
Date Code 20020501
Front-Panel Operations
Front-Panel Layout
The active display points are the first screens in the ROTATING DISPLAY
(see
). Each display points screen shows as many as four
enabled display points. (With 32 display points, the SEL-421 Relay can
present a maximum of eight display points screens.) If a display point does not
have text to display, the screen space for that display point is maintained.
Autoscrolling Mode
Autoscrolling mode shows each screen for five seconds. When you first apply
power to the relay, the LCD shows the autoscrolling ROTATING DISPLAY.
The autoscrolling ROTATING DISPLAY also appears after a front-panel
inactivity time out (see
Front-Panel Inactivity Time Out on page 5.3
). The
relay retrieves data prior to displaying each new screen. The relay does not
update screen information during the five-second display interval. At any time
during autoscrolling mode, pressing
{ENT}
takes you to the MAIN MENU.
Pressing any of the four navigation pushbuttons switches the display to
manual-scrolling mode.
Manual-Scrolling Mode
In the manual-scrolling mode you can use the directional navigation arrow
pushbuttons to select the next or previous screen. Pressing the
{Down}
or
{Right}
pushbuttons switches the display to the next screen; pressing the
{Up}
or
{Left}
pushbuttons switches the display to the previous screen. In manual-
scrolling mode, the display shows arrows at the top and bottom of the vertical
scroll bar. The screen arrows indicate that you can navigate between the
different screens at will. The relay retrieves data prior to displaying each new
screen. Unlike the autoscrolling mode, the relay continues to update screen
information while you view it in the manual-scrolling mode. To return to
autoscrolling mode, press
{ESC}
or wait for a front-panel time out.
Display Points
You can display messages on the SEL-421 Relay front-panel LCD that
indicate conditions in the power system. The relay uses display points to place
these messages on the LCD.
shows a sample display points screen.
The relay has 32 possible display points;
lists the
display points settings. The relay updates the display points data once per
second if you are viewing the display points in manual-scrolling mode; in
autoscrolling mode, the relay updates the display points information each time
the screen appears in the ROTATING DISPLAY sequence.
Figure 5.5
Sample Display Points Screen.
To enable a display point, enter the display point settings listed in
The format for entering the display point data is the following comma-
delimited string:
Relay Word bit,display point name,alias for set state,alias for clear state
Circuit Breaker 1
--Closed--
ROTATING DISPLAY
Press For Menu
Circuit BK1 SF6 Gas
--Alarm--
Circuit Breaker 2
--Closed--
Summary of Contents for SEL-421
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