FOXBORO FBM207B

Description

Discrete inputs can be sensed across all the usual voltage levels found in industrial facilities. The
FBM207/b/c uses one of the several termination assemblies to match to the externally powered voltage level.
In cases where the inputs are critical to the plant’s control scheme, the FBM 207/b/c may be installed as a
redundant pair with standard control blocks used to manage the redundancy.
OVERVIEW
The FBM207/b/c Voltage Monitor/Contact Sense
Input Module functions as a 16-channel DC voltage
monitor or 16-channel contact sensor. Each channel
accepts a 2-wire input from a DC voltage source
(FBM207) or pair of contacts or solid state switches
(FBM207b/ FBM207c). Associated termination
assemblies (TAs) support discrete input signals at
voltages of 60 V DC, 120 V AC/125 V DC, or 240 V
AC. For voltages higher than 60 V DC, the TAs have
additional signal conditioning hardware that provides
voltage attenuation and optical isolation.

The module is available in three distinct types, and
each type with its associated TA supports discrete
inputs as shown below:
Each discrete input is galvanically isolated from other
channels and ground. Group isolated when used
with external excitation.
The module performs signal conversion required to
interface electrical input signals from field sensors to
the redundant module Fieldbus. In addition, it
executes programs for Discrete Input, Ladder Logic,
Pulse Count, and Sequence of Events, with
configurable options of Input Filter Time.
The module can be used as a single unit, or as a
redundant pair (two FBM207s). When used as a
redundant pair, the modules combine to provide
redundancy at the Fieldbus Module (FBM) level, with
field input signals received from one common
termination assembly though a redundant adapter
affixed to the FBMs’ baseplate. The input current for
redundant modules is doubled. A redundant digital
input block in the Foxboro Evo™ Control Software
validates each input in conjunction with information
to/from the module, and selects the input with the
highest quality for processing in the control strategy.
In a redundant configuration, contact sense power
from each module is diode OR’d together in the
redundant adapter to assure redundant power.
A redundant contact input function block, CINR, is
used for each redundant pair of inputs. The CINR
block handles input reads and initialization logic for
the redundant channels. On each execution cycle of
the CINR block, identical reads are sent to both
modules, fully exercising the fieldbus and the logic
circuitry of each module.
FEATURES
Key features of the FBM207/b/c modules are:
 Sixteen discrete inputs
 Supports discrete input signals at voltages of:
• 15 to 60 V DC – contact sense
• 120 V ac/125 V DC – voltage monitoring or
switch inputs
• 240 V ac – voltage monitoring or switch
inputs
 Each input is galvanically isolated. Group isolated
with external excitation
 Single or redundant modules
 Rugged design suitable for enclosures in Class
G3 (harsh) environments
 Executes programs for Discrete Input, Ladder
Logic, Pulse Count, and Sequence of Events with
configurable Input Filter Time option
 Termination Assemblies (TAs) for locally or
remotely connecting field wiring to the FBM207
 Termination Assemblies for per channel internally
and/or externally loop powered devices
 Various Termination Assemblies (TAs) have
additional signal conditioning hardware that
provides voltage attenuation and optical isolation.