INM 937x-FB2-Px-SS Rev 1
2
2
DESCRIPTION
The model numbers shown above comprise SS, increased safety, Ex e enclosures
containing either one (9371 models) or two (9373 models) carrier-mounted 9377-
FB-R fieldbus barrier modules. Each fieldbus barrier module converts a single, non-
intrinsically safe fieldbus trunk into six intrinsically safe (IS) spur connections for
connection to Foundation™ fieldbus H1 fieldbus instruments.
On passing through the enclosure wall, the incoming trunk wiring enters the Trunk
Terminal Area containing increased safety (Ex e) trunk wiring terminals. This assembly
is provided with a protective cover to deter interference, and carries a warning to the
user to isolate the power before working on any trunk wiring.
All enclosure models are supplied with a fieldbus Terminator module (part number F93-
XE) pre-installed in the Trunk Terminal area. This should remain installed if the enclosure
is at the end of the trunk segment. If the incoming fieldbus trunk will be onward linked
to a further node on the segment the terminator should be removed. Further details
are provided in Section 4 of this manual.
All spurs are galvanically isolated from the trunk allowing the user to choose the type
of grounding scheme most suitable to their system.
Short-circuit protection for each outgoing spur is built-in to the 9377-FB-R barrier
module, while surge protection is an option on individual spurs by installing Spur Surge
protection modules (part no. FS32).
A Trunk Surge Protection module (part no. 9376-SP) is another user option and this
can be plugged into a dedicated socket above the Trunk Terminal area to protect the
fieldbus barrier against damaging voltage and current surges on the incoming trunk
wiring.
The enclosures may be installed in a Zone 1 or Zone 2 hazardous area, in which case
the trunk wiring must consist of a suitably protected cable type together with the
appropriate environmental cable glands.
The Stainless Steel enclosure material provides excellent chemical and moisture
resistance and is suitable for use in a wide range of corrosive environments.
The enclosures are bus-powered and require no additional power supply in the field.
When used with a fieldbus host control system, power for the trunk must be provided
ONLY by a supply conforming to IEC 61158-2, e.g. MTL F800 or MTL 918x range of
redundant power supplies.
The enclosure is supplied pre-drilled for all trunk and spur cable entries and can be
supplied blank or fitted with Ex e certified nickel-plated brass blanking plugs and a
breather.
3
MECHANICAL INSTALLATION
See Figures 3.1 and 3.2 for the dimensions, fixing locations and cable gland positions
for both enclosure models.
3 .1 Mounting overview
Before mounting an enclosure, consider the following points.
a) The permitted ambient temperature range external to the enclosure (–40°C to
+70°C) must not be exceeded. Avoid radiant heat by locating the enclosure away
from direct sunlight or local sources of heat.
b) The enclosure has an ingress protection rating of IP66 (to EN60529) so the
mounting location should be chosen to comply with this rating.
c) The enclosure is designed for mounting on a vertical surface, with the cable entry at
the lowest point, as shown in the upper part of Figure 3.1 or Figure 3.2.
d) The nominal weight of the enclosures, excluding any surge protection modules
(trunk or spur) is:
