FBM214B/216B RH924JH HART Communication Input Module

The FBM214b HART Communication Input Module contains eight 4 to 20 mA
individually isolated analog input channels. It supports any mix of standard 4-20 mA
devices and HART devices.
The FBM214b can serve as a HARTcommunications field device host, enabling
Foxboro™ DCS to request and receive two digital messages per second from the field
device. The message pass-through capability can be used to support HART universal,
common practice, and device-specific commands, but it cannot support the burst
communication mode. These commands are implemented using the Foxboro DCS
Field Device Expert for HART. For details, see Field Device Expert for HART Devices
Control and I/O (PSS 41S-10FDMHRT).
The FBM214b provides individually isolated power supplies to power each of the eight
channels.
Optionally, the input channels can be powered by an external power supply. However,
when a common external power supply is used with two or more channels, a Cable
Balun module is required to help prevent HARTcommunication channel crosstalk.

FBM214B P0927AH

8 analog input channels, each accepting one of the following inputs:
◦ Standard 4 to 20 mA analog sensor signal
◦ Digital HART Frequency Shift Keying (FSK) signal superimposed on a 4 to 20
mA analog input signal
• FSK modem dedicated to each input channel for bi-directional digital
communications with a HART field device
• Analog to digital conversion of each of the 4 to 20 mA input signals from the
HART devices
• Support for the HART universal commands necessary to interface the field device
with the Foxboro DCS database
• Per channel galvanic isolation of each of the 8 input channels from each other,
ground and module logic
• Rugged design suitable for enclosure in Class G3 (harsh) environments
• High accuracy achieved by sigma-delta data conversions for each channel
• Termination Assembly (TA) for locally or remotely connecting field wiring to the
FBM214b
• TA for per channel internally and/or externally loop powered transmitters