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2
Chapter
Local Panel User Interface
Relay Front Panel
The figure below shows, as an example, the front panel of the Allen-
Bradley 857 relay and the location of the user interface elements
used for local control.
Figure 2.1 – Front Panel of Allen-Bradley 857 Relay
1. LCD dot matrix display
2. Keypad
3. LED indicators
4. RS-232 serial communication port for PC
Display
The relay is provided with a backlit 128x64 LCD dot matrix
display. The display enables showing 21 characters in one row
and eight rows at the same time. The display has two different
purposes: one is to show the single line diagram of the relay with
the object status, measurement values, identification etc. (Figure
2.2). The other purpose is to show the configuration and
parameterization values of the relay (Figure 2.3).
Figure 2.2 – Sections of the LCD Matrix Display
857-UM001A-EN-P – July 2009
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