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2.3.1 Remote Sensor Mounting – Option RS
Under some circumstances, it is impractical to mount the electronics close to the lens body. Extending the fiber
optic cable is not possible, due to losses that would occur in a longer fiber. However, it is possible to mount the
electronics housing farther from the lens body by mounting the fiber optic adapter (Figure 5) at the end of the
10 feet (3 meters) fiber optic cable, and extending the sensor wires back to the remotely mounted electronics
housing, as shown in Figure 6.
The following considerations should be observed when remotely mounting the fiber optic adapter:
The fiber optic adapter must be mounted in a location with an ambient temperature of 0
F to +185
F
(-18
C to +85
C).
The recommended maximum extension is 25 feet (7.6 meters).
Install twisted cable pair between the fiber optic adapter and the electronics housing. The twisted pair
MUST be run through metallic conduit. Note that F-range models use two twisted pairs (4 wires total).
Other models use a single twisted pair.
Do not install other wires in the same conduit with the sensor wires.
Conduit should be appropriate for the area classification. Seals should be installed near the electronics
housing, in accordance with governing code.
The loop wiring conduit connection on Model HIR is ¾” NPT. Unless the ‘RS’ (remote sensor) option is specified,
the fiber optic adapter is normally factory installed in the ½” NPT opening in the housing.
Wire the electronics module in accordance with local governing code.
A green external earthing screw is located near the threaded conduit entry. An internal green earthing screw is
also provided inside the housing. To connect to the internal earthing screw, you must first move the electronics
module by removing the two screws holding the module down. Replace the module and hold-down screws after
connecting the earth ground conductor.
Note:
If, for any reason, the fiber optic adapter must be unscrewed from the
electronics housing, first make sure the fiber optic adapter sensor wires are
disconnected from the electronics module terminals.
Model HIR
Electronics
Housing
Conduit Seal*
* Provided by user
Conduit Outlet Body
½” NPT
ex Conduit*
Fiber Optic Adapter
½” NPT
Fiber Optic Cable
Figure 6 Typical Installation of Remote Fiber Optic Adapter
