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U.5.10
SEL-421 Relay
User’s Guide
Date Code 20090715
Front-Panel Operations
Front-Panel Layout
Display Points
You can display messages on the SEL-421 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. Display points can show
the status of Relay Word bits or display the value of analog quantities. The
relay has 96 possible display points;
list 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 5.11
Sample Display Points Screen
To enable a display point, enter the display point settings listed in
. All display points occupy one, and only one, line on the display at
all times. The height of the line is determined by the “Text Size” setting
parameter. Display points of single-line height span one screen in total width.
Display points of double-line height span two screens in total width. You can
use multiple display points to simulate multiple lines.
Use the following syntax to display the given Relay Word bit exactly as seen
in the navigational menu (name and value).
DPxx :=
Name
Use the following syntax to display the given Relay Word bit as seen in the
navigational menu, replacing the name of the value with the given alias string.
The text size determines if the display will be in single font or double font. If
the text size is empty, the display will be in single font.
DPxx :=
Name, “Alias”, “Text Size”
Use the following syntax to display the given Relay Word bit with the given
alias. If the Relay Word bit is asserted (logical 1), the LCD displays the set
string in the place of the value. If the Relay Word bit is deasserted (logical 0),
the LCD displays the clear string in the place of the value. One or all of Alias,
Set String, or Clear String can be empty. If Alias is empty, then the LCD
displays only the Set or Clear Strings. If either Set String or Clear String is
empty, then an empty line is displayed when the bit matches that state. The
text size determines if the display will be in single font or double font. If the
text size is empty, the display will be in single font.
DPxx :=
Name, “Alias”, “Set String”, “Clear String”, “Text Size”
Use the following syntax to display the given analog quantity with the given
text and formatting. Formatting must be in the form {Width.Decimal,Scale}
with the value of Name, scaled by “Scale,” formatted with total width “Width”
and “Decimal” decimal places. The width value includes the decimal point
and sign character, if applicable. The “Scale” value is optional; if omitted, the
scale factor is processed as 1. If the numeric value is smaller than the field size
requested, the field is padded with spaces to the left of the number. If the
Circuit Breaker 1
--Closed--
DISPLAY POINTS
Circuit BK1 SF6 Gas
--Alarm--
Circuit Breaker 2
A PH= 119.6 A pri
SF6 ALARM
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