Product Overview

The Allen-Bradley 1797-ACNR15 is a high-performance ControlNet communication adapter designed specifically for the FLEX™ Ex I/O system. This module functions as a critical gateway between a ControlNet network and intrinsically safe I/O modules, allowing for distributed control in Zone 1, Zone 2, and Class I, Division 1 hazardous environments. By integrating intrinsic safety (IS) protection directly into the communication architecture, the 1797-ACNR15 eliminates the need for expensive explosion-proof enclosures or external purges in many volatile industrial applications.

The "R" designation in the model number signifies its support for redundant media. Equipped with dual BNC coaxial connectors, the module maintains simultaneous communication across two independent cables. This dual-path architecture ensures that a single cable failure or signal interruption does not result in system downtime, making it indispensable for continuous process industries where operational continuity is vital for safety and productivity.

Intrinsically Safe Networking and Performance

The 1797-ACNR15 is engineered to meet the most rigorous global standards for hazardous area operation, including ATEX, IECEx, and UL certifications.

• Redundant Communication: Dual ControlNet ports provide automatic seamless switchover between Media A and Media B, ensuring high-availability data transmission.

• High-Speed Throughput: Supports a deterministic 5 Mbps communication rate, providing the rapid response times required for complex safety and process loops.

• Expansion Scalability: A single adapter acts as the bus head-end for up to eight FLEX Ex I/O modules, centralizing the interface for various analog and digital field signals.

• Integrated Diagnostics: Localized LED arrays provide real-time status for the module, power supply, and individual network channels, facilitating rapid fault isolation in the field.

• Simplified Integration: Communicates over standard ControlNet coax, allowing intrinsically safe I/O clusters to be integrated into broader plant-wide ControlLogix® or PLC-5® systems.

Technical Specifications

• Manufacturer: Allen-Bradley (Rockwell Automation)

• Model Number: 1797-ACNR15

• Module Type: FLEX Ex ControlNet Redundant Adapter

• Input Voltage: 24V DC (Intrinsically Safe Power)

• Network Protocol: ControlNet (Coax)

• Communication Rate: 5 Mbps

• I/O Module Capacity: Up to 8 modules per adapter

• Power Dissipation: 4.0 Watts

• Operating Temperature: -20°C to +70°C (-4°F to 158°F)

• Hazardous Area Rating: Class I Div 1; Zone 1 (Intrinsic Safety)

• Dimensions: 3.5 x 13.0 x 14.5 cm

• Weight: 0.9 kg (1.98 lbs)

Hazardous Area Application

The 1797-ACNR15 is the preferred solution for sectors where flammable gases, vapors, or liquids are present:

• Oil and Gas: Remote monitoring of wellhead sensors and valve control on offshore platforms.

• Chemical Processing: Data acquisition from distillation columns and reactor monitoring systems.

• Pharmaceutical: Precision control of volatile chemical mixing and batching processes.

• Paint and Coating: Managing automation in spray booths and solvent storage facilities.