FOXBORO Fieldbus Communications Module, FCM10Ef

I/ASeries® Hardware

Fieldbus Communications Module, FCM10Ef

The FCM10Ef Fieldbus Communications Module is a

fiber optic communications interface which allows the

DIN rail mounted Fieldbus Modules (FBMs) to

communicate with the I/A Series control station over

extended distances using fiber optic cabling. The

FCM10Ef modules provide expanded networking,

easy customization, and greater overall cabling

distances in a fiber optic network (see Figure1). This

configuration is ideally suited for sites in which groups

of FBMs are to be spread apart over greater

distances.

FCM10Ef modules are used with multiport fiber optic

converters (hubs), which connect to the I/ASeries

control station via the high-speed, optionally

redundant 10 Mbps Ethernet trunk Fieldbus.

Up to six groupings of baseplate-mounted FCM10Ef

modules and FBMs can be linked to each optionally

redundant multiport fiber optic converter (hub), for a

maximum of 120 FBMs per I/A Series control station

(depending on selected scan periods). To support

redundancy, a pair of FCM10Ef modules must be

used for each FBM grouping. In non-redundant

configurations, only a single FCM10Ef is required for

each grouping.

Signal transmission distances up to 2 km (1.24 mi)

are possible between the FCM10Ef modules and the

multi-port fiber optic converters (hubs), providing for

wide distribution of the FBM equipment groupings.

Extended transmission distances, using fiber optic

cabling, are also possible within the groupings, and

between the multiport fiber optic converter (hub) and

the I/A Series control station. (Refer to

PSS21H-2W1B3. for details.)

FIBER OPTIC CABLING

Unaffected by electrical noise (EMI, RFI, and

lightning), fiber optic cabling provides a versatile,

highly reliable means of extending signal

communications. It can be used in areas containing

rotating machinery, arc welders, and so forth, and can

be installed in cable trays containing high voltage

power lines, or in outdoor areas exposed to lightning

hazards. Its electrical isolation characteristics provide

protection from voltage differentials and ground loops.

Fiber optic cabling used in this configuration is

purchased by the customer. The recommended fiber

optic cable is a multimode, graded-index glass fiber

with a 62.5 micron core and 125 micron cladding with

0.275 NA (numerical aperture).

Maximum allowable signal loss is 1 dB per km at a

wavelength of 1300 nm, and 3.6 dB per km at a

wavelength of 850 nm. Cables with different

characteristics may not be used. Four fiber optic

cables are required for redundancy, two for transmit

and two for receive connections. For this reason, it is

recommended that the customer purchase duplex

cabling, which consists of two fibers intertwined in a

single cable. The cables must be terminated with

ST-type connectors and cable length may not exceed

that specified for the module.

Other cable requirements (such as flexibility, or

durability) depend on the particular application. Check

with your cable vendor/installer for a listing of

application-specific cable characteristics.