Det-Tronics EA2100CG Eagle 2000 Communication Gateway - Manual (Page 8)

Multiple Wiring Faults
In the event of multiple wiring faults, the nodes between the
faults will continue to function, but the faults will prevent
them from communicating with the main gateway (Figure 4).
In this example, nodes 1 to 4 communicate using one gate-
way port (path A) and nodes 7 and 8 use the other gateway
port (path B). Nodes 5 and 6 are unable to report to the
gateway because they are isolated by the two wiring faults.
Communication with Relay Modules or
Auxiliary Gateways
It is important to note that data will not “pass through”
the main gateway. This means that when a network
wiring fault condition exists, devices communicating on
one side of the main gateway cannot communicate with
devices on the other side of the gateway (Figure 5). In
this example, devices communicating along path A can-
not communicate with devices using path B.
In the event of a single wiring fault, normal communica-
tion will continue between all communication modules
and the main gateway. However, if the system uses a
relay module (Figure 5) and it is configured to monitor
nodes on the other side of the fault, those devices will be
unable to report to the relay module. For example, only
nodes 4 to 6 (Figure 5) are able to communicate with the
relay module. The relay module cannot receive data
from nodes 1 to 3. In the same way, only nodes 1 to 3
will be able to communicate with the Auxiliary gateway.
IMPORTANT
Since it is impossible to predict where a network
fault might occur or exactly what effect it will have
on actual system operation, it is important to diag-
nose and repair any fault as soon as possible after
it is detected to ensure reliable system operation.
Section II
EA2300CM
Communication Module
APPLICATION
The Eagle Communication Module provides communi-
cation capability for a sensing or control device capable
of generating a 4 to 20 ma signal. In addition to the 4 to
20 ma input, the communication module can also simul-
taneously accept two digital contact inputs. Designed
for use with the Eagle communication gateway, the com-
munication module provides a unique technique for
detecting and isolating opens or shorts in the field
wiring. This fault isolation method allows for communi-
cation integrity in the event of a single break or short on
the communication loop. The communication module
circuitry is mounted inside an explosion-proof metal
housing, which is typically mounted beside the associ-
ated sensing or control device.
The Eagle communication module is compatible with
most Det-Tronics flame detection, gas detection or envi-
ronmental monitoring devices.
FEATURES
• Field addressable
• Fault isolation
• Pass through communication circuitry on power loss
• 4 to 20 ma analog input
• Two digital contact inputs
• Non-volatile memory for logging of alarm and cali-
bration events
• Sealed 5 ampere SPDT relay
• 2 adjustable alarm setpoints
• 10 bit signal resolution
• EMI hardened
• Screw terminal connectors
SPECIFICATIONS
INPUT VOLTAGE—
18 to 32 vdc.
INPUTS—
4 to 20 ma analog signal, with an input impedance of
200 ohms in series with a protection diode. Two digital
inputs (for switch or relay contacts). One is dedicated
to either detector calibration or detector fault indication
(refer to the System Configuration Matrix, form 95-8453).
The other is available for general use, with either a nor-
mal or inverted input.
4
A1646
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 4—Communication with Multiple Wiring Faults on the Network
A1647
MAIN
GATEWAY
NODE 1
NODE 6
NODE 2 RELAY
MODULE
NODE 5
NODE 3 NODE 4
PATH A PATH B AUXILIARY
GATEWAY
WIRING FAULT
Figure 5—Network Wiring Fault Affects Communication
with Relay Module and Auxiliary Gateway