Eaton 9372-FB-P Series User manual

9372-FB-Px-xx
5-spur redundant fieldbus barrier
November 2016
INM 9370-RD Rev 5
Instruction manual
MTL fieldbus networks

INM 9370-RD Rev 5
ii
DECLARATION OF CONFORMITY
A printed version of the Declaration of Conformity has been provided separately within the original shipment of goods.
However, you can find a copy of the latest version at http://www.mtl-inst.com/certificates

INM 9370-RD Rev 5 1
CONTENTS
DECLARATION OF CONFORMITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II
GENERAL SAFETY INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
1 OVERVIEW ........................................................................3
2 DESCRIPTION ......................................................................4
2.1 General ................................................................................4
2.2 Configuration options ....................................................................4
2.3 Trunk Terminal Assembly ..................................................................5
3 MECHANICAL INSTALLATION.........................................................5
3.1 Mounting overview ......................................................................5
3.2 Preparation .............................................................................7
3.3 Mounting...............................................................................7
4 INITIAL ELECTRICAL INSTALLATION ...................................................8
4.1 Overview ...............................................................................8
4.2 Grounding ..............................................................................8
4.3 Trunk connections ......................................................................11
4.4 Trunk Terminator module 9378-FT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
4.5 Trunk Surge module 9376-SP .............................................................13
4.6 Spur connections .......................................................................13
4.7 Blanking Plugs .........................................................................14
4.8 Final Checks ...........................................................................15
5 MAINTENANCE ...................................................................15
5.1 General ...............................................................................15
5.2 Fieldbus Barrier maintenance procedures ...................................................15
5.3 Terminator and Trunk Surge Protection modules .............................................17
5.4 Spur connections .......................................................................18
5.5 Trunk connections ......................................................................19
5.6 Regular Maintenance checks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
6 TROUBLESHOOTING ...............................................................20
7 ALARM MODULE - OPERATION & CONFIGURATION .....................................22
7.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
7.2 Device details ..........................................................................22
7.3 Alarm module fitting or replacement.......................................................24
8 ATEX INFORMATION ...............................................................25
8.1 General ...............................................................................25
8.2 Installation ............................................................................25
8.3 Inspection and maintenance .............................................................25
8.4 Repair ................................................................................26
8.5 Marking ...............................................................................26
9 APPENDIX 1 - ENCLOSURE WIRING DIAGRAM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

INM 9370-RD Rev 5
2
GENERAL SAFETY INFORMATION
Safety instructions for installation and operating personnel
The operating instructions provided here contain essential safety instructions for installation personnel
and those engaged in the operation, maintenance and servicing of the equipment.
WARNING!
Failure to comply with these instructions can endanger the lives or health of
personnel and risk damage to the plant and the environment.
WARNING!
The responsibility for planning, installation, commissioning, operation and
maintenance, particularly with respect to applications in explosion-hazard areas,
lies with the plant operator.
Before commencing installation or commissioning:
• Read and understand the contents of this manual
• Ensure installation and operating personnel have received adequate training for this task
• Ensure that any operating instructions are fully understood by the personnel responsible.
• Observe national and local installation and mounting regulations (e.g. IEC 60079-14).
WARNING!
These assemblies may not be used in explosion-hazard area applications if they
have been used previously in general electrical installations.
During operation:
• Make the relevant instructions available at all times to the operating personnel.
• Observe safety instructions.
• Observe national safety and accident prevention regulations.
• Operate the equipment within its published specification.
• Servicing, maintenance work or repairs not described in this manual must not be performed without
prior agreement with the manufacturer.
• Any damage to this equipment may render its explosion protection null and void.
• No changes to any of the components that might impair their explosion protection are permitted.
If any information provided here is not clear:
• Contact Eaton’s MTL product line or one of its representatives.
Note: Improper installation and operation of the enclosure can result in the invalidation of the guarantee.
CAUTION
Earlier models of the Fieldbus Barrier Module (9377-FB) that do not have the “-R” at the
end of the model number cannot be used in the produbts described here.
A mechanical interlock prevents their being fitted to the carriers. Do not attempt to fit
these models as damage to the carrier may result.

INM 9370-RD Rev 5 3
1 OVERVIEW
This manual explains the installation and maintenance procedures for the
9372-FB-xx-yy Redundant Fieldbus Barrier enclosures and must be read in association
with the product datasheets that contain the electrical data.
The 9372-FB-xx-yy Redundant Fieldbus Barriers are field-mounted wiring hubs that create
five (or six*) intrinsically safe spur connections from a high-energy trunk, for connection
to suitably certified Foundation™ fieldbus H1 instruments.They may be installed in
Zone 1 (gas) or Zone 21 (dust) hazardous areas, with the trunk wiring implemented using
suitably protected cable and increased safety (Ex e) connection facilities.
Each enclosure system uses a pair of Fieldbus Barrier modules in a “redundant spur“
configuration to achieve significantly higher system availability than equivalent ‘simplex’
units.The 9372-FB-xx-yy may therefore be selected for critical process applications where
failure of the Fieldbus Barrier would otherwise result in unacceptable downtime or lost
production. It is also ideal for use in Fieldbus Safety Instrumented Function (SIF) networks
in which nuisance trips cannot be tolerated. Failure annunciation to the host control
system is provided by means of an integrated Foundation™ fieldbus device with Digital
Input Function Block capability.
The enclosure options are: electrochemically polished 316 stainless steel or glass-reinforced
plastic (GRP) and either may be installed in a Zone 1 or Zone 2 hazardous area.
The following enclosure types are available by ordering the appropriate model number.
9372-FB-Px-yy 5-spur Redundant Fieldbus Barrier enclosure
9375-FB-Px-yy 6-spur Redundant-ready Fieldbus Barrier enclosure
Where Px = PS (pluggable screw terminal connectors) or
PC (pluggable spring clamp connectors)
and yy = SS (316L stainless steel enclosure) or
PP (GRP enclosure- black)
* See section 2.2
937X-FB-Px-yy Redundant Fieldbus Barrier
5-spur enclosures
Figure 1.1 - Example of model 9372-FB-XX-SS

INM 9370-RD Rev 5
4
2 DESCRIPTION
2.1 General
The standard models comprise a stainless steel or GRP, increased safety, Ex e
enclosure, containing a trunk-wiring terminal assembly (TTA), two carrier-mounted
fieldbus barriers and a fieldbus alarm module.
Each barrier module can convert a single, non-intrinsically safe fieldbus trunk into
six, galvanically isolated, intrinsically safe (IS) spur connections for connection to
Foundation™ fieldbus H1 fieldbus instruments. However, only six spurs are available
at any one time because they are configured as “redundant pairs”. On power-up the
spurs in one barrier are configured to be in “active” mode, while the spurs in the
other barrier remain in “standby”. In the event of a spur circuit failure in the “active”
barrier module, an automatic switchover ensures that the external spur field circuit
continues to be supported by the corresponding spur in the “standby” module.
Figure 2.1 illustrates an example where Module A - on the left- is the active barrier
and Module B the standby. Spurs 1,2, 4, 5 and 6 of Module A are shown as active
(‘A’) but spur 3 has failed (and effectively gone into standby) so module B has
automatically taken control of spur 3 (‘A’) to maintain full service to the affected field
circuit.
++++++

Spur Electronics Spur Electronics
= Active
S= Standby
0V 0V







     

SS SSS
AlarmAlarm
S



Figure 2.1 - Redundant spurs block diagram + optional alarm module
The spurs are galvanically isolated from the trunk allowing the user to choose the
type of grounding scheme most suitable to their system.
Spur short-circuit protection is provided by the barrier and surge protection can
also be added on individual outgoing spurs by the use of individual Spur Surge
protection modules (part no. FS32).
2.2 Configuration options
There are six spur outputs from each barrier and, as described above, these can
operate in a redundant fashion, supporting each other to maintain continuous
availability for field spur devices. However, if a spur “fails-over” to the other barrier,
the situation might go undetected without frequent inspection of the status of the
barrier LEDs. For this reason, a “failure-reporting” configuration is provided, where
Spur 6 is assigned to an internally located Alarm Module (model 9379-ALM) -
see Figure 2.1.

INM 9370-RD Rev 5 5
Consequently, if a spur ‘fail-over’ occurs, an alarm is signalled quickly to the host,
via the fieldbus connection, to facilitate any necessary remedial action.The five
remaining spurs are available to the user for connection to field devices.
Note: A redundant-capable version of the 9372-FB-Px-yy can also be supplied,
part-populated with a single 6-spur module (order as model number 9375-FB-Px-
yy).This permits a future upgrading from the simplex mode to a redundant mode
simply by plugging in an additional Fieldbus Barrier module- and the optional alarm
module, if required.
2.3 Trunk Terminal Assembly
The incoming trunk wiring is terminated inside a separate compartment, called the
TrunkTerminal Assembly (TTA), that contains increased safety (Ex e) trunk wiring
terminals.This assembly has a protective cover to deter interference, and carries a
warning to the user about working on trunk wiring without first isolating the power.
A fieldbusTerminator module (part no. 9378-FT) is supplied pre-fitted on theTTA.This
is to remain installed if the enclosure is at the end of the segment. If the incoming
fieldbus trunk will be onward linked to a further node on the segment the terminator
can be removed. See Section 4.4 on page 13 for additional information.
An optionalTrunk Surge module (part no. 9376-SP) can be plugged into theTTA to
protect the fieldbus barrier against damaging voltage and current surges on the
incoming trunk wiring.
Either enclosure may be installed in a Zone 1 or Zone 2 hazardous area; in which
case, the trunk wiring must be implemented using suitably protected cable.The
enclosures provide excellent chemical and moisture resistance and are suitable for
use in a wide range of corrosive environments.
The 9372-FB-Px-yy and 9375-FB-Px-yy Fieldbus Barrier 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 918x range of redundant power supplies.The
enclosures are supplied pre–drilled for all trunk and spur cable entries and fitted
with Ex e certified 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 IP65 or IP66 (to EN60529)
depending on the manufacturing date. The mounting location should be chosen
to comply with the rating of the enclosure.
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 individual enclosures, including two barrier modules,
but excluding any surge protection modules (trunk or spur) is:
Model type Nominal weight
Stainless steel enclosure 8.0 kg
GRP enclosure 7.8 kg
e) Adequate security should be provided against unauthorised interference.

INM 9370-RD Rev 5
6
Figure 3.1 - External dimensions and mounting hole positions for the stainless steel enclosure
Figure 3.2 - External dimensions and mounting hole positions for the GRP enclosure

INM 9370-RD Rev 5 7
a) All the necessary gland holes have been prepared in the enclosure. One has
a breather fitted and the others are fitted with appropriate blanking plugs.
Where the blanking plugs are replaced by cable gland, the fitted glands must
be Ex e certified and have an ingress protection (IP) rating that maintains the
overall rating of the enclosure.
b) All cable gland holes must be fitted with either a suitable cable gland or
blanking plug.
CAUTION
It is not permitted to create additional holes in the enclosure as this would violate
the certification.
3.2 Preparation
a) Remove any temporary protection or packing materials.
b) The enclosure can be mounted on any suitable structure using the
enclosure’s integral mounting brackets.
c) The fixing bolts must be suitable for the mounting surface and the
environmental conditions.
d) Prepare holes in the mounting surface, on the centres shown in Figure 3.1 or
3.2, to accept suitable screws/bolts for mounting.
e) It is advisable before mounting, to do any necessary replacement of the
cable entry blanking plugs with a suitable gland. For further details see
Section 3.1 f) & g).
3.3 Mounting
WARNING!
To minimise the risk of ignition by electrical apparatus in hazardous
areas, efficient installation, inspection and maintenance of apparatus
and systems is essential, and the work should be carried out by suitably
trained personnel in accordance with the prevailing code of practice.
The certification documents specify “Conditions for safe use” that
must be adhered to and the copy certificate supplied should be
studied and understood. Additionally it is recommend that a working
knowledge of IEC EN 60079 -14 be attained, as this standard provides
guidance in respect to the installation of electrical equipment in
hazardous areas.
3.3.1 The SS enclosure
It is suggested that the upper two fixing bolts have washers fitted before
screwing them into prepared holes to a depth that will allow the enclosure to be
safely hung on them.The enclosure can then be supported on these top bolts
while the lower fixings are put in place. Finally, all fixings can be tightened to
the torque level recommended by their manufacturer.
3.3.2 The GRP enclosure
It is recommended that a washer, not exceeding the 12mm diameter specified in
Figures 3.1 and 3.2, is placed under the head of each of the bolts used to fix the
enclosure to its mounting surface.
NOTE!
It is important to recognise that the hole centres for the middle fixings on the GRP
enclosure are NOT aligned with the holes for the end fixings.
Study Figure 3.2 for full details.
It is suggested that the lower fixings should be put in place first, so that the
enclosure can be supported by them while the upper fixings are put in place.

INM 9370-RD Rev 5
8
After mounting the enclosure
Check that:
• it has not suffered any damage,
• the IP rating is not affected; for example, by distortion of the enclosure,
• the mounting bolts/nuts are all tightened as recommended above.
4 INITIAL ELECTRICAL INSTALLATION
WARNING!
Before starting any electrical installation work, ensure that the
incoming trunk connection is isolated from any source of power.
CAUTION
The temperature inside the enclosure could rise to 75°C. Ensure that all cables and
cable glands fitted are rated to withstand these temperatures.
4.1 Overview
Captive screws are used to secure the lid. Loosen these screws to obtain entry.
CAUTION
The lid of the stainless steel enclosure is connected to the enclosure body with a
protective grounding cable.
DO NOT leave the lid hanging by this link cable while work is carried out!
• The enclosure receives power from the incoming trunk cable and requires no
further source of power.
• The equipment shall only be powered from supplies conforming to IEC 61158.
• Type ‘A’ fieldbus cable is recommended for fieldbus trunk connections.
• The terminal blocks for the trunk fieldbus cables have either screw terminal
connectors or cage clamp connectors according to the enclosure model
specified, but both are suitable for cables from 0.5mm2/AWG 20 up to 2.5mm2/
AWG 14.
On completion of installation, check all blanking plugs and cable glands are tightened
to ensure IP rating of the enclosure is maintained.
Details of the internal wiring for the two enclosure types is provided in Appendix 1.
4.2 Grounding
Two distinct ground concepts should be recognised before wiring of the enclosure
begins:
a) Protective local ground- mandatory
b) Cable shield ground
These two concepts and their implementation are explained below.
4.2.1 Protective local ground
This ground connection is required to ensure that any exposed metalwork in, or
on, the enclosure does not present a hazard to personnel; it also provides a low
impedance earth grounding circuit for any surge protection items used in the
enclosure. An external M10 earth-grounding stud is provided on the side wall of the
enclosure to enable a connection to be made to the local ground.
Use a ring terminal to make a good quality, plant safety-earth connection (4mm2
cross-sectional area or better) to this bolt and tighten it to a recommended torque of
5Nm.
Note: It is important to prevent this connection from loosening and also to protect it
from corrosion against the stainless steel grounding stud.
4.2.2 Cable shield ground
The enclosures can be configured by the user to either of two grounding methods.The
user should adopt the one that conforms to their system’s normal grounding method.

INM 9370-RD Rev 5 9
NOTE:
Whichevermethodisused,itisimportanttoconnectthescreen/shieldtoground
at one end of the cable only.
The cable shield is normally electrically isolated from the protective earth
ground, although the two may be deliberately interconnected in some
grounding arrangements.The cable shield wiring of the trunk and spur cables
should be connected to the local terminals marked with an ‘S’.
The following options are available to the user.
WARNING!
The following may involve changes to wiring in the Trunk Terminal
Assembly. No part of the Trunk Terminal Assembly may be worked
while the enclosure is powered, unless the environment is known to
be non-hazardous.
4.2.2.1 Single point of grounding at host; trunk & spur shields interconnected








 


  








Figure 4.1 - Option 1
In many installations, the preferred method of grounding is to ground the
fieldbus cable shields at one point only, normally at the fieldbus power supply.
In this case, the trunk and spur cable shields are connected to each other at
the Fieldbus Barrier and are not connected to ground in the field. For this
arrangement, connect the carrier shield ground wire (marked A) intoTerminal 2.
Note: this is the default grounding method for factory-supplied 937x-FB enclosures.
IMPORTANT NOTE
937x-FB enclosures are factory-supplied with Option 1 grounding. If power is
applied locally, for example during commissioning, when the trunk cable shield
is NOT providing a ground connection, the spur cable shields must be grounded
according to Option 2.
When the trunk cable shield ground has been fully instated (or restored), the
grounding method should be returned to Option 1.
4.2.2.2 Trunk shield grounded at host; spur cable shields grounded at barrier












  






 
Figure 4.2 - Option 2
With this arrangement, the fieldbus trunk shield is separated from the spur cable
shields. It should be adopted if plant or local regulations require that the spur
cable shields be grounded at the Fieldbus Barrier. For this arrangement, connect the
carrier shield ground wire (marked A) intoTerminal 3.

INM 9370-RD Rev 5
10
T
Host
Control
System
Fieldbus
Power
Supply
9372-FB
5/6-spur enclosure
9377-FB-R Fieldbus Barrier
module
(5/6-spur)
123
Fieldbus instruments
Non-
intrinsically
safe trunk
T
9377-FB-R Fieldbus Barrier
module
(5/6-spur)
Alarm module
6
Alarm module
6
Alarm module
6
Intrinsically
safe spur
45
T
Host
Control
System
Fieldbus
Power
Supply
9377-FB-R Fieldbus Barrier
module
(5/6-spur)
123
Fieldbus instruments
Non-
intrinsically
safe trunk
9377-FB-R Fieldbus Barrier
module
(5/6-spur)
Intrinsically
safe spur 45
9377-FB-R Fieldbus Barrier
module
(5/6-spur)
123
Fieldbus instruments
9377-FB-R Fieldbus Barrier
module
(5/6-spur)
Intrinsically
safe spur
45
9372-FB
5/6-spur enclosure
9372-FB
5/6-spur enclosure
T
Figure 4.3 - Trunk Connection Options

INM 9370-RD Rev 5 11
Note: After configuring the required grounding option, tighten all screw terminals to
a recommended torque of 0.6 Nm.
4.2.3 Permitted enclosure combinations
The maximum number of redundant intrinsically safe spurs that can be supported
on a trunk segment is 12.The permitted enclosure combinations are shown in Figure
4.3.
Note that a fieldbus trunk terminator (9378-FT) must be fitted (see Section 4.4) to the
last/furthest enclosure on the segment. See also Figure 4.6.
4.3 Trunk connections
Each enclosure is provided with two access holes for trunk glands; one for the
incoming trunk and another for onward linking to an additional enclosure, if
necessary.
WARNING!
No part of the Trunk Terminal Assembly may be worked while the
enclosure is powered, unless the environment is known to be non-
hazardous.
4.3.1 Trunk Terminal Assembly
Inside the enclosure, the trunk cables are terminated in aTrunkTerminal Assembly
(TTA). This is a sub-enclosure with a protective lid, secured with a single screw.This
assembly, together with its warning label, is intended to deter a user from working
on the trunk connections without isolating trunk power. See Figure 4.4.
Trunk cables enter via glands, through the enclosure wall shown at the bottom of
the diagram, and the grounding stud is accessible on the lower left side.The trunk
terminal connectors are in the middle of the assembly to receive the trunk wiring.
Terminals are provided to allow a variety of wiring arrangements, according to the
particular requirements of the installation:
– “Trunk In” cable only
– “Trunk In” and “Trunk Out” cables
– Active and spare “Trunk In” cables
– Active and spare “Trunk In” cables with overall cable shield
– Active and spare “Trunk In” cables and “Trunk Out” cable
CAUTION
The ‘+’ and ‘–’ wires of a ‘spare’ trunk in cable must be connected only to terminals
marked ‘NC’. This ensures that the spare cable is not electrically connected in parallel
with the ‘active’ trunk in or trunk out cables. The cable shield of the spare cable
should be connected to an ‘S’ terminal.
All ‘spare’ trunk-in connections (‘+’, ‘–’ and shield) must be firmly grounded at the
host.
4.3.2 Trunk cable wiring
Cable ferrules should be fitted to all multi-stranded cables being terminated in the
TTA.
Connect the trunk cable(s) in the following way.
a) Loosen the captive screw of the transparent protective cover on theTTA. Slide
out the cover and move it to one side to obtain access.
b) Prepare the trunk cable(s) in accordance with the gland manufacturer’s
instructions and feed the cable(s) through the gland(s).
c) Connect the prepared ends of the fieldbus trunk cable(s) into the appropriate ‘+’
, ‘–‘ and ‘S’ terminals, shown in Figure 4.5, and tighten the screw terminals to a
recommended torque of 0.6 Nm.

INM 9370-RD Rev 5
12
Cover
retaining
screw
Position of
Trunk Surge
module
(optional)
Terminator
module
Slide
protective
cover in this
direction
to remove Trunk
wiring
terminals
Trunk
cable entry
area
Protective
ground
stud
Enclosure
wall
Figure 4.4 - Trunk Termination Assembly (TTA)
  
Active
Spare
    
  
Overall
shield
Trunk in
(with Active + Spare cable pairs)

  


    
  



Figure 4.6 - Active & Spare ‘Trunk In’ cables plus
‘Trunk Out’ cable
Figure 4.5 - ‘Trunk In’ with Active & Spare cable
pairs

INM 9370-RD Rev 5 13
Note: Figure 4.5 shows the screw-terminal ‘-PS’ enclosure option, but the ‘-PC’
cage-clamp terminal arrangement is similar.
Check Section 4.2.2 on page 8 to confirm that the chosen fieldbus-ground option
is correctly wired, and adjust if necessary.
a) Tighten the gland securing nut(s), ensuring that any cables are not strained.
b) Replace the transparent protective cover over the terminal block and secure it
with the retaining screw to a recommended torque of 0.6 Nm.
4.4 Trunk Terminator module 9378-FT
If the enclosure provides the last (or only) spur connections on the segment, the
trunk must be terminated correctly to ensure that the optimum signal quality is
maintained.The TrunkTermination Assembly (TTA) has provision for an 9378-FT
Terminator module to be fitted when required.
NOTE
A terminator should be used only at the end points of the trunk wiring.
Connecting a terminator at any other point on the trunk will degrade the
signal.
The 9378-FT is a two-pin module that plugs into the upper end face of theTrunk
Terminator Assembly. See Section 5.3 on page 17 for fitting and removal details.
4.5 Trunk Surge module 9376-SP
The 9376-SPTrunk Surge module can be fitted to theTTA to prevent damage to the
equipment from voltage and current surges that could occur on the trunk wiring.
The 9376-SP is a four pin module that plugs into the upper end face of theTrunk
Terminator Assembly. See Section 5.3 on page 17 for fitting and removal details.
4.6 Spur connections
Refer to Figure 4.7 for additional details.
The spur cables can be connected directly onto the fieldbus barrier carrier or
through a Spur Surge module (FS32). If Spur Surge modules are not used, Section
4.6.2 on page 14 can be ignored.
4.6.1 Connecting the spur cables
Prepare the spur cables in accordance with the gland manufacturer’s instructions
and secure the cables in the glands.
IMPORTANT
• When fitting the cable in the gland allow 20 – 30mm of available cable length
outside the enclosure to allow for cable adjustment if a Spur Surge module
is taken out of circuit inside the enclosure. See Section 5.4.1 on page 19 for
further details
• Cable ferrules must be fitted to any stranded cable or screen wiring that is
being used.
Connect the prepared ends of the fieldbus spur cables into the ‘+’, ‘S’ and ‘–’
terminals on the carrier (or surge module, if fitted), making sure that the same
polarity is observed for all spurs.

INM 9370-RD Rev 5
14
4.6.2 Fitting FS32 Spur Surge modules
Spur Surge modules are pluggable units that integrate easily with the standard
pluggable connector and which direct excessive spur surge currents to the protective
local ground.
Figure 4.7 - FS32 Spur Surge module on carrier
To fit an FS32:
1. Unscrew the two captive screws securing the standard pluggable connector
(supplied on the carrier) and remove it from its socket.
2. Insert the FS32 module into the now vacant socket on the carrier, tighten the two
side securing screws to a recommended torque of 0.4 Nm.
3. Ensure also that the central “protective ground” screw is engaged and tightened
to a recommended torque of 0.4 Nm to provide a low impedance path for surge
currents.
4. Fit the connector (removed at Step 1 above) into the socket on the FS32 and
tighten its two securing screws also to a recommended torque of 0.4 Nm.
Removal of a Spur Surge module is the reverse of the fitting process. See also Section
5.4.1 on page 18 for information on cable ‘adjustment’ if one of these modules is
taken out of use.
4.7 Blanking Plugs
Blanking plugs of factory-supplied Fieldbus Barriers are lightly tightened for ease of
removal. Any blanking plugs that are not removed from the fieldbus barrier must be
tightened to the required torque to meet the IP rating.
Two types of blanking plug are supplied with the Fieldbus Barrier as shown in figures 4.8
and 4.9 below and should be tightened to a torque rating as shown in the table below.
Type A 4.8Nm
Type B 12Nm
Figure 4.8 - Type A Blanking plug Figure 4.9 - Type B Blanking plug

INM 9370-RD Rev 5 15
4.8 Final Checks
Before replacing the lids on the enclosure, check:
• that all cable glands and any blanking plugs are tightened securely.
• that all cable glands are tightened to provide the required IP seal in accordance
with gland installation instructions.
• that the protective trunk wiring cover is in place on theTrunkTerminal Assembly.
• that no tools (e.g. screwdrivers) or loose items have been left in the enclosure.
• that there is no damage to any cover seal, otherwise it must be replaced with one
that has the same manufacturer’s part number.
• that if, and only if,the enclosure is the last one on the fieldbus segment, that a
9378-FTTerminator module is fitted into the socket on theTTA.
• that the required grounding link is securely connected between the enclosure lid
and the enclosure body.
Fit the enclosure lid and tighten all of its securing screws to a recommended torque
of 2.5 Nm.
5 MAINTENANCE
When the enclosure is installed in a hazardous area it is important for personnel to
understand what activities are permissible when fieldbus power is present and what are
not.
WARNING!
Read and understand what work is permitted inside the enclosure.
Failure to comply with these instructions can endanger the lives
or health of personnel and risk damage to the plant and the
environment.
5.1 General
The following items in the enclosure may be removed or disconnected while the
trunk is still powered.
• 9377-FB-R Fieldbus Barrier module(s)*
• 9378-FTTerminator module
• 9376-SPTrunk Surge module
• 9379-ALM Alarm module
• FS32 Spur Surge modules and any spur wiring
All other wiring in the enclosure requires the trunk power to be isolated, or a gas
clearance certificate to be obtained before any work is carried out.
* NOTE
The standard, non-redundant 9377-FB barrier cannot be fitted in place of the
9377-FB-R; it has built-in mechanical differences to prevent its substitution.
5.2 Fieldbus Barrier maintenance procedures
The 9377-FB Fieldbus Barrier is designed to tolerate the failure of one or more
spur circuits in either Fieldbus Barrier module. However, a failed module should
be replaced as quickly as possible to avoid any loss of power or communication
to the spurs from subsequent failures. If a barrier module has one or more LED
indicators showing solid red, meaning that the internal spur circuits have failed (see
“Troubleshooting”), then it should be replaced.

INM 9370-RD Rev 5
16
5.2.1 Fitting and removal techniques
The individual 9377-FB-R Redundant Fieldbus Barrier module(s) may be fitted or
removed without isolating the trunk power.The trunk connections to the barrier
module on the carrier have spark suppression by design and cannot cause ignition
while they are being connected or disconnected.This section should be read to
understand the physical removal or installation of a barrier, but read 5.2.2 on
page 16 to understand the recommended procedure for replacing a barrier when
powered.
5.2.1.1 Removing a Fieldbus Barrier module (refer to Figure 5.1)
a) Loosen the three captive fixing screws (C & D) on the module to release it.The
screws are all spring-loaded and should retract when the thread has disengaged.
b) Slowly pull the 9377-FB-R Fieldbus Barrier module away from its connections on
the carrier until the safety retaining clip (B) stops further removal.
c) Press the clip (see bold black arrow) towards the module until the barrier is
released and can be removed completely.
5.2.1.2 Fitting a Fieldbus Barrier module (refer to Figure 5.1)
Note: Before fitting a 9377-FB-R Fieldbus Barrier module check the connection pins
on its underside to ensure that they have not been bent or damaged in any way.
Do not use, or attempt to repair, a barrier module that has any of its pins bent or
damaged, because this might affect its safety and will invalidate the certification.
a) Engage the locating guides (A) of the 9377-FB-R Fieldbus Barrier module into the
sockets provided on the carrier and push the module fully into place.
b) Tighten the three captive fixing screws (C & D) to a recommended torque of
0.9Nm to secure it.
A
B
D
C
C
Fail-over
button
AB
Figure 5.1 - Fieldbus Barrier module – fitting & removal
5.2.2 Use of Fail-over button when replacing a barrier
The following technique is recommended for the replacement of a barrier. Do
not remove the ‘active’ barrier of a redundant pair as this may cause loss of
communications to a fieldbus device.
Two fail-over button are provided to permit a manual transfer of control status from
Active to Standby e.g. A > B or B > A. By switching all spurs to a fully operative
barrier module, ‘active’ operation can be maintained during module replacement.
The following example illustrates a typical “hot-swap” procedure.

INM 9370-RD Rev 5 17
Key to symbols in the digram: Note: Only spur LEDs shown for clarity.
= Active, healthy (solid) = Standby, failed (pulse)
= Standby, healthy (pulse)
Step 1
1. Spur #3 on Barrier A has failed and shows pulsing red.
Control of this spur has transferred automatically to
Spur 3 of Barrier B, which has changed from a
flashing green to a solid green. Barrier A needs to be
replaced to restore redundant service.
Step 2
2. Press the A > B fail-over button, beside Barrier
A, to pass spur control to Barrier B. Barrier B LEDs
should all change to solid green and all LEDs on
Barrier A should pulse to indicate that Barrier A is
now in ‘standby’ mode and Barrier B has become the
‘active’ barrier.
3. Barrier A can now be removed from the carrier
(following the procedure in Section 5.2.1.1) and
replaced with a known good module. After replacement, Barrier A remains in
‘standby’.
4. To restore Barrier A to ‘active’ mode, press the B > A fail-over button located
beside Barrier B. Control of all spurs now returns to Barrier A while Barrier B returns
to ‘standby’ mode.
* NOTE
Operating the fail-over buttons will not allow active spurs to be transferred to a
missing, failed spur or failed barrier module.
5.3 Terminator and Trunk Surge Protection modules












Figure 5.3 - Module connectors and retaining clips

INM 9370-RD Rev 5
18
5.3.1 Fitting and removal
Both modules have connectors that are designed to prevent an ignition-
capable spark when the module is installed or removed.The modules are not
interchangeable but the method of installing and removal is the same.
Do not use, or attempt to repair, a module that has any of the pins on its underside
bent or damaged, because this might affect its safety and will invalidate the
certification.
5.3.1.1 Mounting a module
Refer to Figure 5.4.
Orientate the module so that the smaller front clip is facing the user, then:
• lower the module so that the safety retaining clip on theTTA housing fits into the
loop on the module
• locate the terminal pins into their contact sockets on theTTA housing and
• push the module home until front and rear retaining clips engage.
5.3.1.2 Removing a module
Refer to Figures 5.3 and 5.4 for further information.
Removal is a two-step process that first breaks the electrical connection, followed by
the physical removal of the module from theTTA.
• Press the clip at the rear of the module and tilt the module forward until the clip
disengages at the rear.
• Press the front clip and withdraw the module from its socket until it is stopped
by the safety retaining clip, then press down on the safety retaining clip enough
to release it and pull the module away from theTTA body without rotating or
twisting it.






Figure 5.4 - Mounting a module - e.g. Trunk Surge Protection module
5.4 Spur connections
All of the spur connections are intrinsically safe and therefore may be live-worked
in a hazardous area without ‘gas clearance’, while complying with normal ‘permit to
work’ procedures. If spur wiring is removed from a connecting plug, ensure that the
same polarity is observed when it is reconnected.
For addtional information refer to Section 4.6 on page 13.