6
9440300990 Rev J
Controls and Indicators
DECS-250
Table 1. Front Panel Control and Indicators Descriptions
Locator
Description
A
Display.
The liquid crystal display (LCD) serves as a local source of information
provided by the DECS-250. The LCD displays operating setpoints, loop gains,
metering, protection functions, system parameters, and general settings. The 128 by
64 dot pixel, backlit LCD displays white characters on a blue background.
B
Pre-Position Indicator.
This red light emitting diode (LED) lights when the active mode
setpoint is at any of the three pre-position (predefined) settings.
C
Limit Indicators.
Two red LEDs indicate when the active mode setpoint reaches the
minimum or maximum value.
D
Scrolling Pushbuttons.
These four buttons are used to scroll up, down, left, and right
through the menus displayed on the LCD (locator A). During an editing session, the left
and right scrolling pushbuttons select the variable to be changed and the up and down
scrolling pushbuttons change the value of the variable.
E
Reset Pushbutton.
This button cancels editing sessions, resets alarm annunciations
and latched alarm relays, and can be used for quick access to the metering screen.
F
Communication Port.
This type B USB jack connects the DECS-250 with a PC
operating BESTCOMS
Plus
®
for local communication. BESTCOMS
Plus
is supplied
with the DECS-250.
Caution
In accordance with the guidelines defined in USB standards, the USB
port on this device is not isolated. To prevent damage to a connected
PC or laptop, the DECS-250 must be properly tied to ground.
G
Edit Pushbutton.
Pressing this button starts an editing session and enables changes to
DECS-250 settings. At the conclusion of the editing session, the Edit pushbutton is
pressed to save the settings changes.
H
Null Balance Indicator.
This green LED lights when the setpoint of the inactive
operating modes (AVR, FCR, FVR, var, and PF) match the setpoint of the active
mode.
I
PSS Active Indicator.
This red LED lights when the integrated power system stabilizer
is enabled and can generate a stabilizing signal in response to a power system
disturbance.
J
Internal Tracking Indicator.
This red LED lights when any inactive mode (AVR, FCR,
FVR, Var, or Power Factor) is tracking the setpoint of the active mode to achieve a
“bumpless” transfer when changing active modes.
Menu Navigation
The DECS-250 provides local access to DECS-250 settings and metering values through a menu
structure displayed on the front panel LCD. An overview of the menu structure is illustrated in Figure 3.
Movement through the menu structure is achieved by pressing the four scrolling pushbuttons.
Summary of Contents for DECS-250
Page 2: ......
Page 6: ...iv 9440300990 Rev J Revision History DECS 250 ...
Page 16: ...xiv 9440300990 Rev J Contents DECS 250 ...
Page 20: ...4 9440300990 Rev J Introduction DECS 250 ...
Page 28: ...12 9440300990 Rev J Power Stage DECS 250 ...
Page 32: ...16 9440300990 Rev J Voltage and Current Sensing DECS 250 ...
Page 40: ...24 9440300990 Rev J Synchronizer DECS 250 ...
Page 52: ...36 9440300990 Rev J Auxiliary Control DECS 250 ...
Page 56: ...40 9440300990 Rev J Contact Inputs and Outputs DECS 250 ...
Page 84: ...68 9440300990 Rev J Limiters DECS 250 ...
Page 114: ...98 9440300990 Rev J Power System Stabilizer DECS 250 Figure 96 PSS Parameter Settings ...
Page 124: ...108 9440300990 Rev J Stability Tuning DECS 250 ...
Page 126: ...110 9440300990 Rev J Mounting DECS 250 Figure 103 Overall and Projection Mounting Dimensions ...
Page 127: ...9440300990 Rev J 111 DECS 250 Mounting Figure 104 DECS 250 Escutcheon Plate Dimensions ...
Page 198: ...182 9440300990 Rev J Timekeeping DECS 250 ...
Page 210: ...194 9440300990 Rev J CAN Communication DECS 250 ...
Page 304: ...288 9440300990 Rev J Maintenance DECS 250 ...
Page 316: ...300 9440300990 Rev J Specifications DECS 250 ...
Page 334: ...318 9440300990 Rev J Analog Expansion Module DECS 250 ...
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