Foxboro GW30 Gateway Processor 30

Termination Assemblies and Cables

Field I/O signals connect to the FBM subsystem via DIN rail mounted termination

assemblies (TAs). Multiple types of TAs are available with FBM217 to provide input

signal connections, signal conditioning, optical isolation from signal surges and

external power connections for field devices. Since these features are built into the

termination assemblies (where required), in most applications there is no need for

additional termination equipment for field circuit functions such as circuit protection or

signal conditioning (including fusing and power distribution).

The termination assembly can be used with a single FBM217 or with a redundant pair

(two FBM217s).

The DIN rail mounted termination assemblies connect to the FBM subsystem

baseplate by means of removable termination cables. When used with a redundant

module pair, the termination assembly is connected to the baseplate using a

redundant adapter (RH926ZY).

The cables are available in a variety of lengths, up to 30 meters (98 feet), allowing the

termination assemblies to be mounted in either the enclosure or in an adjacent

enclosure. See Functional Specifications- Termination Assemblies, page 14 for

termination cable part numbers and specifications.

Migration Use of Termination Assemblies

WhenanFBM217isusedto replace 100 Series FBMs, its associated termination

assembly is determined based on which 100 Series FBM is being replaced. Typically,

the 100 Series FBM being replaced was a main FBM and may have been used in

conjunction with an expansion FBM.

Asingle FBM217 provides the I/O communications for both the 100 Series equivalent

main and expansion TAs. To provide enough terminals for the field input wiring, two

termination assemblies are used with the FBM217- one for the field input wiring for

the replaced main FBM, and one for the field input wiring for the replaced expansion

FBM.

The “expansion” termination assembly is daisy-chained to the “main” termination

assembly via the expansion cables listed in Table 3. page 20.

See Functional Specifications- Termination Assemblies, page 14 for a list of the

termination assemblies needed to replace both the 100 Series main FBMs and the

expansion FBMs.

Alternatively, the FBM217 can accept field wiring through a Termination Assembly

Adapter (TAA) instead of the termination assemblies when upgrading 100 Series

FBMs. This is discussed in Termination Assembly Adapter Modules for 100 Series

Upgrade (PSS 41H-2W4)

Discrete Inputs

Various termination assemblies are available to support the interfacing of field signals

to the low level FBM input circuits. Active termination assemblies support input signal

conditioning for the FBM as well as channel isolation.

Be aware that for configurations which use main and expansion TAs, the I/O signal

conditioning circuits are designed to emulate the 100 Series FBM I/O subsystem. This

provides for functional I/O equivalence during upgrades from 100 Series to 200 Series

hardware.

The signal conditioning circuits are located on daughter boards that are mounted

under the component covers of the termination assemblies. To condition signals,

these termination assemblies provide optical isolation, current limiting, voltage

attenuation and optional terminal blocks to connect externally supplied excitation

voltage