Foxboro DCS FBM206Pulse Input Module
Overview

Features
Measurement of a machine's rotational speed is often accomplished using a device
that transmits high speed pulses. The FBM206 provides the means to accept up to
eight of these pulse signals (up to 25kHz) and provide the values to the Foxboro™
DCS. The FBM206baccepts up to four pulse inputs and provides up to four 0 to 20
mAoutputs for associated controls.
The FBM206contains eight pulse input channels, and the FBM206b provides four
pulse input channels and four 0 to 20 mA analog output channels. Each input channel
accepts a 2-wire, pulse input signal from a sensor. Input devices include vortex and
turbine meters, solid state or electromechanical contacts, and other sensors with
similar pulse outputs.
The modules perform the signal conversion required to interface the electrical input
signals from the field sensors to the redundant fieldbus.
• FortheFBM206.eight 7 to 27 VDC, configurable, pulse input channels
• FortheFBM206b,four 7 to 27 VDC,configurable, pulse input channels and four
0 to 20 mAanalog output channels
• Eachinput channel accepts a pulse input with a maximum rate of 25 kHz
• Eachchannel is galvanically isolated from the other channels and ground
• Ruggeddesignsuitable for enclosure in Class G3 (harsh) environments
• Execution of the pulse input application program with configurable options for
Pulse Rate Totalization and Resolution (on a per module basis) and Meter
Scaling Factor
• Termination Assemblies (TAs) for locally or remotely connecting field wiring to the
FBM206/206b
• TAsforperchannel internally and/or externally loop powered devices
Standard Design
The FBM206/206b module has a rugged extruded aluminum exterior for physical
protection of the circuits. Enclosures specially designed for mounting the Fieldbus
Modules (FBMs) provide various levels of environmental protection, up to harsh
environments, per ISA Standard S71.04.
Visual Indicators
Light-emitting diodes (LEDs) incorporated into the front of the module provide visual
status indications of FBM functions.
Easy Removal/Replacement
The modules can be removed/replaced without removing field device termination
cabling, power or communication cabling
Fieldbus Communication
AFieldbus Communication Module or a Control Processor interfaces the 2 Mbps
module Fieldbus used by the FBMs. FBM206 accepts communication from either path
(A or B) of the redundant 2 Mbps Module Fieldbus. If one path is unsuccessful or is
switched at the system level, the module continues communication over the active
path.
Modular Module Mounting
The modules mount on a 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 redundant fieldbus, redundant independent DC power,
and termination cables.
Termination Assemblies
Field I/O signals connect to the FBM subsystem via DIN rail mounted TAs. The TAs
used with FBM206 are described in Functional Specifications- Termination
Assemblies, page 12.


Termination Assemblies and Cables
Field input signals connect to the FBM subsystem via DIN rail mounted Termination
Assemblies, which are electrically passive. TAs for the FBM206 are available in the
following forms:
• Compression screw type using Polyamide (PA) material
• Ringlug type using Polyamide (PA) material
See Functional Specifications- Termination Assemblies, page 12 for a list of TAs used
with the FBM206.
Aremovable termination cable connects the DIN rail mounted TA to the FBM via a
field connector on the baseplate in which the FBM is installed. Termination cables are
available in the following materials:
• Polyurethane
• LowSmokeZeroHalogen(LSZH)
Termination cables are available in a variety of lengths, up to 30 meters (98 feet),
allowing the Termination Assembly to be mounted in either the enclosure or in an
adjacent enclosure. See Table 2 for a list of termination cables used with the TAs for
the FBM206 and FBM206b.

Use of Termination Assemblies in 100 Series Upgrade
Subsystem
WhenanFBM206bisusedto replace the 100 Series FBM06. it may use any of the
appropriate termination assemblies listed above for the FBM06’s field I/O wiring.
Alternatively, the FBM206b can accept this field wiring through a Termination
Assembly Adapter (TAA) instead of a termination assembly. This is discussed in
Termination Assembly Adapter Modules for 100 Series Upgrade (PSS 41H-2W4).
