INSTALLATION

MOUNTING

MTL-Relcom Redundant Fieldbus Power Systems (FPS) are designed for

mounting on 35mm DIN rail. For maximum cooling, the DIN rail should

be mounted horizontally so that air can flow vertically between the

power modules.

INPUT POWER SUPPLY CONNECTIONS

For redundant operation, two separate DC power supplies should be

connected to each FPS. Four pairs of terminals are provided on each

FPS for this purpose; two pairs for each input power supply. The extra

pair of terminals for each input power supply are intended to be used

for connection to another FPS installed immediately adjacent to the first.

Prefabricated jumper assemblies are included with each FPS-I for this

purpose. When multiple Fieldbus Power Systems are wired together

using jumper assemblies, redundant connections should be made to the

two input power supplies using the terminal pairs located at each end of

the row of systems.

Each power module provides galvanic isolation of 250V ac between

the fieldbus segment and the input power supplies. Each FPS-I supplies

350mA at 25V dc to the fieldbus segment. This output is maintained

even if only one power module is installed. This level of output power

allows for construction of very long fieldbus segments with a large

number of bus-powered transmitters. Each FPS provides both power

conditioning and input power supply redundancy to each fieldbus

segment.

LED indicators on each power module and near each of the two input

power supply connections give clear visual indication that components

are functioning properly. To minimize system downtime, an alarm circuit

provides notification if any of the power supply components fail. This

allows failed components to be replaced so that power system integrity

is maintained.

The alarm circuitry is galvanically isolated from the fieldbus segments

and input power supplies. The two power modules plug into a DIN rail

mounted backplane (Redundant Coupler or RCT) that contains one

segment terminator and provides connections to the two input power

supplies, H1 host system, fieldbus trunk cable, and alarm circuitry.

A bus configuration is used for the input power and alarm connections

so that up to eight fieldbus power systems can be easily wired together

to share input power supplies and provide a common alarm circuit.

Pictured above is a Redundant Fieldbus Power Supply with connections

to the Fieldbus H1 host shown at the top of the picture.

Segments that do not require the high availability provided by

redundant power conditioning may be operated with only a single

FPS-IPM. To prevent an unwanted alarm condition due to the second

FPS-IPM not being fitted, a blanking module should be installed in the

blank slot. These are supplied in a pack of 10 as part number FPS-BLK10.

• Redundant power conditioner for high availability applications

• Replace power modules without resetting the fieldbus

• High power output

• Two levels of power redundancy

• Component failure alarm

• Integrated fieldbus terminator

• Simplified power wiring

The MTL-Relcom redundant fieldbus power system (FPS-I range)

provides redundant power conditioning for fieldbus  network segments

and facilitates the connection of redundant bulk DC supplies. The system

is fully ‘hot-swappable’ meaning that individual power conditioning

modules and input power supplies can be replaced without interrupting

power or communication on the fieldbus segment. An alarm circuit

provides warning in case of a power conditioning module or input power

supply failure. The system is designed so that power for several fieldbus

segments can be provided from a single cabinet with minimal wiring.

One fieldbus segment terminator is built into each power system.

Each FPS includes two plug-in power modules. These modules function

as power conditioners, providing impedance between the input DC

power supply and the fieldbus. This impedance is necessary to prevent

the input DC power supply from degrading the digital fieldbus signal.

The 9372-FB Redundant Fieldbus Barrier is based on MTL’s revolutionary

9370-FB Series products, which are supplied as complete, factory-assembled

enclosure systems that do not require additional wiring, customised housings or

complex ancillary components. Electrical and mechanical aspects of the design are

integrated, providing the industry’s first complete, ergonomic solution for ‘High

Energy Trunk’ applications in hazardous areas.

Uniquely, the key modular components of the system (Fieldbus Barrier, Terminator

and Surge Protectors) may be ‘hot-plugged’ by design and without gas-clearance

procedures or separate isolating switches. This virtually eliminates the risk associated

with hazardous area maintenance activities, speeds module replacement and avoids the

need for specialist operator training.

Optional features include pluggable surge protection components for the fieldbus

trunk and individual spurs. Connection facilities with generous room for cable

management are provided within the Fieldbus Barrier enclosure for the trunk and

spur wiring.

For added flexibility, a redundant-capable enclosure can be specified part-populated

with one 6-spur module (model no. 9375-FB). This permits future upgrading from

simplex to redundant mode simply by plugging in an additional Fieldbus Barrier

module and optional alarm module.

The 9372-FB Fieldbus Barrier is bus powered and requires no additional power

supply in the field. When used with a fieldbus host control system, power for the trunk

may be provided by redundant MTL-Relcom power supplies.

Each enclosure system uses duplicated Fieldbus Barrier modules in a redundant

configuration to achieve significantly higher system availability than equivalent

‘simplex’ units. The 9372-FB 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.

In common with conventional Fieldbus Barriers, each intrinsically safe spur is

capable of supporting a FISCO or ‘Entity’ certified fieldbus device located in a Zone 0 or 1

hazardous area. The short-circuit protected spurs are galvanically isolated from the trunk

and require no protective ground connection in the field.