Det-Tronics EA2100CG Eagle 2000 Communication Gateway - Manual (Page 7)

sive calibration. Unlike the communication module, the
DCU allows the operator to view three status indicating
LEDs through a viewing window on the enclosure cover.
The DCU is available in three different models to allow
use with a variety of sensing devices.
Refer to Section III of this manual for a complete
description of DCU operation.
NETWORK EXTENDER – EA2400NE
The EA2400NE Network Extender expands the capabilities
of the Eagle system by allowing additional nodes as well
as additional wiring to be added to the communication
loop. Without a network extender, the communication net-
work is limited to 60 nodes on a 2000 meter loop. Each
network extender, however, increases the capacity of the
loop by up to 60 nodes and 2000 meters of wiring, up to a
maximum of 250 nodes and 10,000 meters of wiring.
The electronic circuitry is mounted inside an explosion-
proof metal housing for installation in hazardous loca-
tions.
Refer to Section V of this manual for a complete
description of network extender operation.
RELAY MODULE – EA2500RM
The Eagle Relay Module monitors a selected group of
detection nodes on the digital communication loop. The
relay module is furnished with a sealed SPDT relay and
generates an output when the selected criteria for out-
put actuation are met.
The specific status conditions to which the relay module
will respond are selected at the time of configuration.
These can include one or more of a variety of fault,
alarm or calibration events.
The relay module must be configured to operate in either
the common alarm mode or the voting mode. When
configured to operate as a common alarm, the relay is
actuated when an event specified for output actuation
occurs at any of the nodes within the specified block of
addresses on the loop. Alternatively, the relay module
can perform a voting function, monitoring up to 8 detec-
tion nodes in a zone and actuating its relay when an
event specified for output actuation occurs at a minimum
number of nodes within the zone (selectable from 1 to 8).
All electronic circuitry is contained inside a watertight,
explosion-proof aluminum enclosure that is designed for
installation in hazardous locations.
Refer to Section VI of this manual for a complete
description of relay module operation.
NETWORK OPERATION
DURING A FAULT CONDITION
The Eagle system utilizes a unique method for detecting
an open or short in the communication network wiring.
This state-of-the-art feature minimizes the possibility of a
communication breakdown in the event of a wiring fault
in the communication loop and can also serve as an aid
in troubleshooting.
The communication network is constructed as a loop
that starts and ends at a pair of ports on the main gate-
way. The nodes communicate with the main gateway
over the digital highway (Figure 2). Communication
between the gateway and the communication modules
normally occurs through the first gateway port.
Each communication module contains both the hardware
and software necessary to isolate it in the event of a wiring
fault. If a short occurs somewhere in the network wiring,
the gateway annunciates the fault, while the fault isolation
circuitry in the communication modules isolates the section
of the network where the fault has occurred. Normal com-
munication continues over the network utilizing the second
network communication port of the gateway (Figure 3).
A single open or short on the digital highway will not affect
normal system communication between the communication
modules and the main gateway, since communication is re-
established with the gateway from the other direction utiliz-
ing the second network communication port. Normal sys-
tem communication will continue until the wiring problem
can be repaired. However, two exceptions must be noted:
1. Multiple wiring faults
2. Communication involving devices other than
communication modules.
3 95-8424
A1644
NODE 1 NODE 8
NODE 3 NODE 6
NODE 2 NODE 7
NODE 4 NODE 5
MAIN
GATEWAY
Figure 2—Normal Communication over the Digital Highway
A1645
MAIN
GATEWAY
NODE 1 NODE 8
NODE 3 NODE 6
NODE 2 NODE 7
NODE 4 NODE 5
PATH A PATH B
WIRING FAULT
Figure 3—Communication with a Single Wiring Fault on the Network