FOXBORO FBM202 Thermocouple/mV Input Module
FOXBORO FBM202 Thermocouple/mV Input Module
The FBM202 Thermocouple/mV Input contains eight thermocouple input channels, and one isolated RTD
reference junction compensation channel.
OVERVIEW
The FBM202 Thermocouple/mV Input contains eight
thermocouple input channels, and one isolated RTD
reference junction compensation channel (for terminal
temperature sensing). Each thermocouple/mV
channel accepts standard thermocouples for various
temperature ranges, and each provides
thermocouple burnout detection (up-scale). The
inputs are galvanically isolated from other channels
and ground.
The module performs the signal conversion required
to interface the electrical input signals from the field
sensors to the optionally redundant Fieldbus. It
executes an Analog Input application program, which
provides integration time and Rate of Change Limits
configurable options
Two types of passive termination assemblies are
available for the FBM202:
DIN rail mounted TAs, similar to those used with
the other 200 Series FBMs
Baseplate-mounted TA, which mounts directly
onto the field I/O connectors of the 200 Seriesbaseplate. These TAs provide field I/O wiring
support for two FBM202s in paired slots (that is,
in positions 1 and 2. 3 and 4. 5 and 6. or 7 and
8), as shown in Figure 1
When connected to the appropriate TAs, the
FBM202 module provides functionality formerly
provided by the 100 Series FBM I/O subsystem. TAs
are available which support the functionality of the
100 Series FBM02.
FBM202
FEATURES
Key features of the FBM202 are:
Eight channels for input of thermocouple signals
One isolated RTD reference junction
compensation channel (for terminal temperature
sensing)
Each input channel is galvanically isolated
Rugged design suitable for enclosure in Class G3
(harsh) environments
Execution of an analog input application program
that provides conversion time and configurable
options for Rate of Change Limits
High accuracy achieved by sigma-delta data
conversions for each channel
Termination Assemblies (TAs) for locally or
remotely connecting field wiring to the FBM202
HIGH ACCURACY
FBM202
For high accuracy, the module incorporates Sigma
Delta data conversion on a per-channel basis, which
can provide new analog input readings every 25 ms,
and a configurable integration period to remove any
process noise and power line frequencies.
Each time period, the FBM converts each analog
input to a digital value, averages these values over
the time period and provides the averaged value to
the controller.
STANDARD DESIGN
FBM202 has a rugged extruded aluminum exterior
for physical protection of the circuits. Enclosures
specially designed for mounting the FBMs provide
various levels of environmental protection, up to
harsh environments, per ISA Standard S71.04.
VISUAL INDICATORS
Red and green light-emitting diodes (LEDs)
incorporated into the front of the module provide
visual status indications of the FBM operational
status.
EASY REMOVAL/REPLACEMENT
The module can be removed/replaced without
removing field device termination cabling, power, or
communications cabling.
FIELDBUS COMMUNICATION
A Fieldbus Communications Module or a Control
Processor interfaces to the redundant 2 Mbps
module Fieldbus used by the FBMs. The FBM
accepts communication from either path (A or B) of
the 2 Mbps Fieldbus — should one path fail or be
switched at the system level, the module continues
communication over the active path.
MODULAR BASEPLATE MOUNTING
The module mounts on a DIN rail mounted
baseplate, which accommodates up to four or eight
Fieldbus Modules. The Modular baseplate is either
DIN rail mounted or rack mounted, and includes
signal connectors for redundant Fieldbus, redundant
independent dc power, and termination cables.
TERMINATION ASSEMBLIES
Field I/O signals connect to the FBM subsystem via
a:
DIN rail mounted TA, or
Baseplate-mounted TA.
The TAs used with the FBM202 are described in
“FUNCTIONAL SPECIFICATIONS – TERMINATION
ASSEMBLIES” on page 8