FOXBORO AD198GV

Description

FOXBORO AD198GV
Redundant Analog Inputs
If a failure is detected in one of the modules, its output is driven to 0 mA and the
corresponding channel in the good module automatically continues supplying the
proper current to the output current loop.
Each output channel drives an external load and produces a 0 to 20 mA output.
Outputs are combined in series through the redundant adapter. The microprocessor of
each module executes the analog I/O application program, plus security routines that
validate the health of the FBM.
Configurable options in the modules for output security include Fail-Safe Action (Hold/
Fallback), Analog Output Fail-Safe Fallback Data (on a per channel basis), Fieldbus
Fail-Safe Enable, and Fieldbus Fail-Safe Delay Time. The Analog Output Fail-Safe
Fallback Data option must be set for 0 mA output. This removes one of the pair of
redundant output channels from service for detectable problems such as a module not
properly receiving output writes or not passing security tests on FBM microprocessor
writes to output registers. Setting of the Analog Output Fail-Safe Fallback Data option
for 0 mA output also minimizes the possibility of a “fail high” result.
Visual Indicators
Light-emitting diodes (LEDs) incorporated into the front of the module provide visual
indication of the module’s operational status, and communication activity of the
channels. Two additional LEDs provide the master or tracker status of the modules.
Easy Removal/Replacement
The module mounts on a Compact 200 Series baseplate which is either DIN rail
mounted or rack mounted horizontally, and includes signal connectors for redundant
fieldbus, redundant independent dc power, and termination cables. Two screws on the
FBM secure the module to the Compact 200 Series baseplate.
Redundant modules must be located in adjacent positions on the baseplate, with the
first module located in an odd-numbered position (for example, the positions labelled
“3” and “4”). To achieve redundancy, a redundant adapter module is placed on the two
adjacent baseplate termination cable connectors to provide termination for a single
cable (see Figure 1). A single termination cable connects from the redundant adapter
to the associated termination assembly (TA).
The module can be removed/replaced without removing field device termination
cabling, power, or communication cabling.
Fieldbus Communication
A Fieldbus Communication Module or a Control Processor interfaces the redundant 2
Mbps module Fieldbus used by the FBMs. The Compact FBM218 module accepts
communication from either path (A or B) of the redundant 2 Mbps fieldbus. If one path
is unsuccessful or is switched off at the system level, the module continues
communication over the active path.