Foxboro FBM217 Discrete Input Module

Foxboro FBM217 Discrete Input Module

Description

The Compact FBM217 Discrete Input Interface Module provides 32 input channels, each accepting a 2-wire input from a dc voltage source. Associated termination assemblies (TAs) provide for discrete inputs of under 60 VAC, 120 VAC/125 VDC or 240 VAC. The module performs signal conversion required to interface the electrical input signals from the field sensors to the FCP or ZCP. It is part of the Compact 200 Series I/O subsystem described in Compact 200 Series I/O Subsystem Overview (PSS 41H-2COV).

Depending on the type of I/O signal required, the TAs contain current limiting devices, high voltage attenuation circuits, optical isolation and external power source connections.

The module can be used as a single unit, or as a redundant pair. When used as a redundant pair, the modules combine to provide redundancy at the Foxboro DCS Fieldbus Module (FBM) level, with field input signals received from one common termination assembly though a redundant adapter affixed to the FBMs' baseplate. The field input current for redundant modules is doubled. A redundant digital input block in the control software validates each input in conjunction with information to/from the module, and selects the input with the higher quality for processing in the control strategy.

In a redundant configuration, contact sense power from each module is diode OR'd together in the redundant adapter to verify redundant power.

A redundant contact input function block, CINR, is used for each pair of inputs. The CINR block handles input reads and initialization logic for the redundant channels. On each execution cycle of the CINR block, identical reads are queried from each module, fully exercising the fieldbus and the logic circuitry of each module.

Features

• 32 discrete inputs
• Supports discrete input signals at voltages of:

    15 to 60 VDC

    120 VAC/125 VDC

    240 VAC

• Single or redundant modules
• Compact, rugged design suitable for enclosure in Class G3 (harsh) environments
• Executes the programs for Discrete Input, Ladder Logic, Pulse Count, and Sequence of Events, with the configurable options: Input Filter Time and FailSafe Configuration
• Various Termination Assemblies (TAs) that contain:

    High voltage attenuation and optical isolation for inputs

    External power connection for device excitation

    Main/expansion TA functionality

Technical Specifications