Schweitzer Engineering Laboratories SEL-749M, Instruction Manual

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8.3
Date Code 20080918 Instruction Manual SEL-749M Relay
Front-Panel Operations
Human-Machine Interface
Front-Panel Security
Front-Panel Access Levels
The SEL-749M front panel typically operates at Access Level 1 and provides
viewing of relay measurements and settings. Some activities, such as editing
settings and controlling output contacts, are restricted to those operators who
know the Access Level 2 passwords or can disable these passwords from the
front panel.
Pressing the {Left Arrow} and {Right Arrow} pushbuttons for 10 seconds toggles
the PASSWORD DISABLE/ENABLE if passwords are set. When you disable
passwords, through use of the front-panel pushbuttons, the SALARM Relay
Word bit asserts for one second. Use caution when including the SALARM
Relay Word bit in the control logic.
In the figures that follow, restricted activities are indicated by the padlock
symbol shown in
Figure 8.2 .
Figure 8.2 Access Level Security Padlock Symbol
Before you can perform a front-panel menu activity that is marked with the
padlock symbol, you must enter the correct Access Level 2 passwords. After
you have correctly entered the password, you can perform other Access
Level 2 activities without reentering the password.
Access Level 2 Password Entry
When you try to perform an Access Level 2 activity, the relay determines
whether you have entered the correct Access Level 2 password since the front-
panel inactivity timer expired. If you have not, the relay displays the screen
shown in
Figure 8.3 for you to enter the password.
Figure 8.3 Password Entry Screen
Password=
Del Clr Accept
A B C D E F G H
I J K L M N O P
Q R S T U V W X
Y Z . . . . . .
a b c d e f g h
i j k l m n o p
q r s t u v w x
y z . . . . . .
0 1 2 3 4 5 6 7
8 9 . . . . . .
! " # $ % & ' (
) * + , - . / :
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] ^ _ ` { | } ~
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