FBM218 FOXBOROFEATURES
Key features of the Compact FBM218 module are:
Eight channel-isolated output channels, each
providing one of the following outputs:
• Standard 4 to 20 mA analog output signal
• Digital HART Frequency Shift Keying (FSK)
signal superimposed on a 4 to 20 mA analog
output signal.
Module pair offers redundancy at the FBM level
FSK modem dedicated to each output channel
for bi-directional digital communications with a
HART field device
Support for HART universal commands
necessary to interface the field device with the
Foxboro Evo™ system
Galvanic isolation of all output channels from
each other, from ground, and from module logic
Compact, rugged design suitable for enclosure in
Class G3 (harsh) environments
Termination Assemblies (TAs) for locally or
remotely connecting field wiring to the Compact
FBM218.
OVERVIEW
The Compact HART Communication Redundant
Output Interface Module (FBM218) contains eight
channel-isolated output channels. The Compact
FBM218 supports any mix of standard 4 to 20 mA
devices and HART devices, and is part of the
Compact 200 Series I/O subsystem described in
Compact 200 Series I/O Subsystem Overview
(Reference 1). (See Table 3, “Reference Documents,”
on page 12 at the end of this document.)
A pair of the modules combines to provide
redundancy at the Fieldbus Module (FBM) level, with
field output signals wired to one common termination
assembly (see Figure 1). In this configuration, one
Compact FBM218 is the Master, and the other is the
Tracker.
The Compact FBM218 serves as a HART
communications field device host, enabling the
Foxboro Evo system to request and receive two
digital messages per second from each field device.
The Compact FBM218’s design is narrower than the
standard 200 Series FBMs. It has a rugged
acrylonitrile butadiene styrene (ABS) 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.
The Compact FBM218 module offers redundant modules for eight output channels, each providing a 4 to
20 mA output signal or a digital HART® signal superimposed on a 4 to 20 mA analog output signal.
