Sel 751A, Instruction Manual

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4.112
SEL-751A Relay Instruction Manual Date Code 20100129
Protection and Logic Functions
Front-Panel Settings (SET F Command)
To optimize the time you spend on setting the device, only the number of
enabled display points and enabled local bits become available for use. Use
the front-panel LCD timeout setting FP_TO as a security measure. If the
display is within an Access Level 2 function when a timeout occurs, such as
the device setting entry, the function is automatically terminated (without
saving changes) after inactivity for this length of time. After terminating the
function, the front-panel display returns to the default display. If you prefer to
disable the front-panel timeout function during device testing, set the LCD
timeout equal to OFF. Use the front-panel LCD contrast setting FP_CONT to
adjust the contrast of the liquid crystal display. Use the front panel auto-
message setting FP_AUTO to define displaying of Trip/Warning message. Set
FP_AUTO either to Override or add to the Rotating display when the relay
triggers a Trip/Warning message. Set RSTLED := Y to reset the latched LEDs
automatically when the breaker or contactor closes.
Display Points
Use display points to view either the state of internal relay elements (Boolean
information) or analog information on the LCD display. Although the LCD
screen displays a maximum of 16 characters at a time, you can enter up to 60
valid characters. Valid characters are 0–9, A–Z, -, /, ", {, }, space. For text
exceeding 16 characters, the LCD displays the first 16 characters, then scrolls
through the remaining text not initially displayed on the screen.
Boolean Display Point Entry Composition
Boolean information is the status of Relay Word bits (see Appendix J: Relay
Word Bits ). In general, the legal syntax for Boolean display points consists of
the following four fields or strings, separated by commas:
Relay Word Bit Name, “Alias,” “Set String,” “Clear String.”
Any or all of Alias, Set String, or Clear String can be empty. Although the
relay accepts an empty setting Name as valid, a display point with an empty
Name setting is always hidden (see below). Commas are significant in
identifying and separating the four strings. Use quotation marks only if the
Table 4.59 LCD Display Settings
Setting Setting Prompt Range Default
FP_TO LCD TIMEOUT OFF, 1–30; min 15
FP_CONT LCD CONTRAST 1–8 5
FP_AUTO FP AUTOMESSAGES OVERRIDE,
ROTATING
OVERRIDE
RSTLED CLOSE RESET LEDS Y, N Y
where:
Name = Relay Word bit name (IN101, for example). All binary
quantities occupy one line on the front-panel display (all
analog quantities occupy two lines).
Alias = A more descriptive name for the Relay Word bit (such as
TRANSFORMER 3), or the analog quantity (such as
TEMPERATURE).
Set String = State what should be displayed on the LCD when the
Relay Word bit is asserted (CLOSED, for example)
Clear String = State what should be displayed on the LCD when the
Relay Word bit is deasserted (OPEN, for example)