Allen-Bradley 1797-ACNR15 FLEX Ex ControlNet Ex Redundant Media Adapter Module

Description

The 1797-ACNR15 is an intrinsically safe communications adapter designed for the FLEX Ex distributed I/O platform. This module forms the intelligent link between a central programmable automation controller and localized FLEX Ex input/output architectures operating within classified hazardous boundaries. It manages high-speed serial data exchanges and provides a structural interface that passes communication and power down the local backplane via an integrated FlexBus connection without compromising the system energy constraints.

Equipped with dual coaxial ports, the device executes redundant media control routing to maintain consistent communication links even in the event of a physical trunk line failure. The 1797-ACNR15 operates natively on ControlNet networks, converting standard communication payloads into low-energy signals rated for explosive gas, vapor, or dust environments. It is extensively installed in off-shore oil rigs, chemical processing areas, tank monitoring systems, and pharmaceutical batch plants requiring localized control nodes directly within hazardous zones.

Features

• Dual ControlNet BNC ports providing native media redundancy for high-availability systems.
• Intrinsically safe circuitry enabling reliable operation directly within classified areas.
• Built-in galvanic isolation mechanisms separating field-side elements from main bus architectures.
• Node address configuration via accessible integrated front-panel switches.
• Comprehensive diagnostic light-emitting diodes displaying active network statuses and fault codes.

Applications

• Offshore production platforms utilizing continuous safety shutdown networks.
• Chemical refining facility zone-mounted remote I/O concentration points.
• Petroleum storage tank farms requiring high-uptime telemetry aggregation.
• Specialty grain processing silos with explosive atmospheric conditions.

Technical Specifications

Connections/Interfaces

Installation Guidelines

DIN Rail Mounting

Tilt the module at a slight angle and catch the rear mounting clip on the upper edge of a standard 35 mm x 7.5 mm DIN rail. Rotate the unit downward flush with the track until the integrated locking tab clicks into a fully engaged orientation.

Grounding Requirements

This hardware is grounded directly through the structural DIN rail to a dedicated intrinsic safety earth ground. Always utilize zinc-plated yellow-chromate steel DIN rails. Do not use poor conductor paths like aluminum or plastic rails which can degrade or break the safety ground path.

Communication Tap Connections

Remove the factory protective insulator boots from the BNC jacks before seating. Click the primary media drop line firmly into Channel A. Secure the backup cable to Channel B to achieve media redundancy. Torque terminal screw connections to 0.8 to 1 N-m (5 to 7 lb-in).

Power Constraints

Ensure this module is driven solely by an approved intrinsically safe external power supply block. Verify that voltage and current limits on the delivery side never exceed the specific technical boundary limits assigned to this unit.

FAQ

What protocol does this communications component utilize?

It communicates across industrial networks using the specialized ControlNet version 1.5 specification.

Does this hardware module provide automatic path switching if a wire breaks?

Yes, the dual BNC connection layout supports automatic control routing across the redundant line without stopping system logic.

Can this unit be mounted directly inside a Zone 1 explosion-prone environment?

Yes, the device is engineered with intrinsic safety protections allowing deployment within classified locations when housed in an appropriate metal enclosure.

What is the maximum number of extension units this adapter can control?

The module is capable of addressing and powering a maximum backplane stack of eight discrete FLEX Ex modules.

How is the network node identifier set on this assembly?

The node address is selected by manually clicking the integrated push switches found on the side or front of the housing enclosure.

Can a standard commercial power source be wired into this device?

No, it must receive operational potential exclusively from an approved intrinsically safe power network supply line.

What function do the color LED displays perform on the faceplate?

The light indicators provide real-time updates regarding communication line status, local module errors, and power rail parameters.

Is it safe to configure or disconnect lines while the terminal remains powered?

Do not touch or disconnect field cabling unless the surrounding environment is verified to be non-hazardous or power has been totally isolated.

What specific type of coaxial network cabling is recommended?

It is designed to connect to quad-shield RG-6/U type coaxial media runs such as the factory 1786-RG6 cables.

Does this device feature conformal coating protections?

Yes, the module boards receive a factory conformal coating layer to insulate components against airborne corrosive elements.