Wire Relay Connection; Rs-485 Communication Network; Figure 19 - 4 Wire Relay Connection - GasTech F-Guard-IR3-H2 User Manual

4 Wire Relay Connection

This wiring option uses the fault and alarm relay and are connected to fire alarm panels. This
connection allows to connect several detectors on 4 wires in a single loop. On the last detector there
is a connected EOL resistor in the connection box. The value of the resistor depends on the control
panel specification.
The number of detectors in a single loop depends on the control panels power supply capacity and
length on wire width.
In fault condition, the fault relay will open the contact. The control panel will see an open loop and
will report a fault.
In alarm condition, the alarm relay will close the contact and short the loop. With this configuration,
the panel does know which detector in the loop caused the alarm or fault. See figure below.

RS-485 Communication Network

Using the RS-485 network capability of the detector and communicator software, it is possible
to connect up to 32 detectors in an addressable system with only 4 wires (2 for power and 2 for
communication). Using repeaters, the number of detectors can be much larger (32 detectors for
For more information & technical support:
F-Guard IR3-H2 User Manual
F 19 - 4 W R
IGURE IRE ELAY
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C
ONNECTION
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