FOXBORO Compact FCM2F2 Fieldbus Communication Module

OVERVIEW

Fieldbus Communication Modules (FCMs) are fibre optic communication extenders that allow 200 Series fieldbus modules to be remotely mounted near plant processes.

FCM2F2 (RH914YZ), FCM2F4 (RH917JA) and FCM2F10 (RH916TQ)

Three models are available with nominal maximum substrate-to-substrate fibre optic cabling distances: up to 2 km (1.24 mi), 4 km (2.48 mi) and 10 km (6.21 mi) respectively.

FCMs are mounted in pairs on standard baseboards for redundancy. Non-redundant configurations require only a single FCM.

Fibre optic cabling is unaffected by electrical noise (EMI, RFI and lightning) and is a versatile and highly reliable means of extending signal communications.

It can be used in areas containing equipment such as rotating machinery, arc welders, etc. It can also be installed in cable bridges containing high voltage power lines, or in outdoor areas exposed to lightning hazards.

or outdoor areas exposed to lightning hazards. Its electrical isolation features protect against voltage differences and ground loops.

FCM Design

The FCM has a rugged extruded aluminium enclosure that provides physical protection for the circuitry.

Enclosures specifically designed for the installation of FBMs and FCMs provide varying degrees of environmental protection for the FCM, up to harsh environments (Class G), in accordance with ISA Standard S71.04.

The FCM can be removed/replaced from the base plate without power failure. six light-emitting diodes (LEDs) on the front of the FCM.

Six light-emitting diodes (LEDs) on the front of the FCM are used to indicate the status of network activity with the modular fieldbus and fibre-optic link, as well as the operational status of the FCM.

Figure 1 shows an example of a redundant configuration where the baseboards (containing the FCM) are connected point-to-point via fibre optic cable.

The cabling configuration shows a single fibre optic segment connecting two substrates. However, up to three fibre segments can be used to connect four baseboards (maximum).

The maximum fibre cabling distance between any two base stations is 10 km (using FCM2F10s (RH916TQ)).

The total fibre optic cabling distance (all cable segments) between base stations does not exceed 20 km (10.42 miles).

Baseboard Module Mounting

The FCM is mounted on a standard baseboard. The baseboard includes signal connectors for fieldbus, power, and I/O cable connections.

A baseboard can support up to eight FBMs, or a combination of FBMs and FCMs.

When connecting two baseboards with fibre optic cables (redundant), one pair of FCMs per baseboard is required (four FCMs total).

For non-redundant configurations, only one FCM is required per baseboard.

Multiple baseboards in the same cabinet do not necessarily require FCMs and fibre optic cables.

Any baseboards within 60 metres (196.85 feet) can be connected together with standard twisted-pair cabling.

Fibre Optic Cabling

Fibre optic cables for fieldbus connections to these modules are purchased by the customer.

The fibre optic cable required for the FCM2F2 (RH914YZ) and FCM2F4 (RH917JA) connections is multimode, graded-indexed glass fibre.

The core is 62.5 micron, the cladding is 125 micron and the NA is 0.275 (numerical aperture).

125 micron cladding with 0.275 NA (numerical aperture). At a wavelength of 1300 nm

Maximum allowable signal loss is 1 dB per kilometre at 1300 nm and 3.6 dB per kilometre at 850 nm.

Cables must be terminated with ST-type connectors. Cables with different characteristics must not be used.

The cable required for the FCM2F10 (RH916TQ) connection is a standard single-mode fibre optic cable with ST-type connectors.

Other cable requirements (such as flexibility or durability) depend on the specific application.