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Entellisys Low-Voltage Switchgear
Section 6. EntelliGuard Messenger
The EntelliGuard Messenger (see Figure 6.1) is
located above each circuit breaker cubicle and
provides the interface between the CPUs and the
EntelliGuard circuit breaker. The Messenger provides
analog-to-digital conversion of the current signals
taken from the breaker cubicle-mounted current
sensors and of the voltage signals taken from
voltage transformers connected to the switchgear
bus. Any close, open, trip, or lockout commands
issued to the circuit breaker by the CPU are trans-
lated by the Messenger and result in signals to the
appropriate coils on the circuit breaker. Feedback
from the circuit breaker, confirming any operation,
is sent back through the Messenger to the CPU.
An EntelliGuard Messenger is configured at the
factory with the appropriate breaker frame rating,
current sensor rating, and overcurrent trip charac-
teristics for each circuit breaker cubicle in the
switchgear line-up. The front panel of the Messenger
has two rotary switches for setting the trip rating of
the breaker installed in the associated cubicle. One
switch selects the current setting of the cubicle based
on the installed current sensors. This is similar to the
selection of a rating plug for a traditional breaker
trip unit. The other switch selects the long time
(overload) pick-up setting for the circuit (50-110%
of the current setting). Table 6.1 lists the available
current sensor values and associated current settings.
The Messenger has the following user-interface,
programming, and protection features.
Indicator LEDs
Front panel LEDs show the location and operating
status of the circuit breaker and the health of the
system electronics, and they aid in programming
the system.
Figure 6.1
EntelliGuard Messenger
• Locator LED . Positioned at the left end of the LED
array, the blue Locator LED is used for programming
the system and breaker control functions. When
preparing to set any of the breaker protective
functions, the Locator LED is set to flash for either
10 or 30 seconds and provides visual verification,
from the front of the switchgear, that the intended
circuit is being correctly addressed. The Locator
LED can also be used in the same manner prior to
executing a breaker CLOSE, OPEN, or TRIP command
from the HMI. Entellisys also provides preventative
maintenance information for each circuit breaker
based on the fault duty of the breaker. The
Locator LED can be used to correctly identify a
circuit breaker when using the preventative
maintenance screens on the HMI.
• Communication LED . Two green LEDs (labeled
Com 1 and Com 2) provide status indication of
the two communication channels to each
Messenger. An illuminated LED indicates the
communication wiring between the Messenger
and the CPU is intact and information is being
transmitted and received.
• Power LED. Two redundant sources of 120v AC
power each Messenger. The green Power LED
indicates the Messenger is receiving proper 120v
AC control power.
• Breaker status LEDs . Two LEDs indicate circuit
breaker OPEN / CLOSE status. The green LED
indicates the breaker is open. The red LED indicates
the breaker is closed. The red LED also monitors the
breaker shunt trip coil and its control power source.
Test Port
The Messenger is provided with a DB-type 25-pin
connector, accessible from the front panel, for
connection to the Entellisys portable test kit. Seven
analog signals representing three-phase voltages
and currents plus neutral current are injected
25
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