FOXBORO Compact FBM240. Redundant with Readback, Discrete

S71.04.

High Reliability

The redundancy of the module pair, coupled with the high coverage of detected faults,

provides a very high subsystem availability time.

The module performs signal conversion required to interface electrical input signals

from field sensors to the optionally redundant Fieldbus. It executes the Discrete I/O

program with the following configurable options: Input Filter Time, Fail-Safe

Configuration, and Sustained or Momentary Outputs. If the Momentary Output

configuration is selected, then Pulse Output Interval is also configurable.

Whenredundant, either module may be replaced without upsetting field input or

output signals to the good module. The module can be removed/replaced without

removing field device termination cabling, power, or communications cabling

Easy Removal/Replacement

The module mounts on a Compact 200 Series baseplate. Two screws on the FBM

help secure the module to the baseplate.

Redundant modules must be located in adjacent positions on the baseplate, with the

first module located in an odd-numbered position (for example, the positions labelled

“3” and “4”). To achieve redundancy, a redundant adapter module is placed on the two

adjacent baseplate termination cable connectors to provide termination for a single

cable (see Figure 1). A single termination cable connects from the redundant adapter

to the associated termination assembly (TA).

Whenredundant, either module may be replaced without upsetting field input signals

to the good module. Each module can be removed/replaced without removing field

termination cabling, power, or communications cabling.

Modular Baseplate Mounting

The Compact FBM240module mounts on a DINrail mounted Modular Baseplate,

which accommodates up to four or eight FBMs. The Modular Baseplate is either DIN

rail mounted or rack mounted, and includes signal connectors for the redundant

Module Fieldbus, redundant independent DC power, and termination cables.

Redundant modules must be located in odd and even adjacent positions on the

baseplate (positions 1 and 2. 3 and 4. 5 and 6. or 7 and 8). To achieve the

redundancy, a redundant adapter module is placed on the two adjacent baseplate

termination cable connectors to provide a single termination cable connection (See

Figure 1. page 3).

To system configurator applications and to other systems monitoring through SMON,

Foxboro DCS System Manager, and SMDH, redundant FBM240s appear to be

separate, nonredundant modules. The functional redundancy for these modules is

provided by their associated control blocks.

Redundant Modules in Foxboro DCS HMI

The redundant pair of modules appear as two independent modules to system

management software applications (such as Foxboro DCS System Manager and

Termination Assemblies

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

assemblies (TAs). The TAs used with the Compact FBM240 provide:

• Outputsignal connection points

• External power connection point

• 5Aunsealedrelay or a 10 Aunsealed relay for each output

• 15-60VDCswitch andvoltage monitor inputs

The relay TAs have a high voltage input circuit that monitors the voltage across the

contacts of each output relay. Monitor circuits are located on daughter card

assemblies mounted on the TAs. There are two daughter cards per TA, each with four

monitor circuits. The TAs are:

• RH917YF-80to125VDCat5Aor80to120VACat10A

• RH917HU-80to120VACat5A

• RH926SZ-15to30VDCat5A

• RH916AQ/RH916AR-15to60VDCvoltagemonitor and 2 Aswitch

NOTE: WhentheCompact FBM240output opens, the TA contacts still apply

current to the circuit due to the TA’s readback circuitry, as described in Table 2 and

Table 3.

The RH916AQ/ARpassive TA provides fused 2 A outputs and independent inputs for

use with 15-60 VDC.

The redundant adapter connects the redundant FBM’s baseplate connectors together.

The redundant adapter provides a single termination connection to a single TA.

The DIN rail mounted termination assemblies connect to the redundant adapter by

means of a removable termination cable. The cable is available in a variety of lengths,

up to 30 meters (98 feet), allowing the termination assemblies to be mounted as

needed by plant design.

Visual Indicators

Red andgreen light-emitting diodes (LEDs) incorporated into the front of the modules

provide visual status indications of FBM functions, as well as the discrete states of the

individual output points.