Product Overview of the Allen-Bradley 1794-ACNR

The Allen-Bradley 1794-ACNR belongs to the 1794 Flex I/O series. This device acts as a communication gateway for industrial controllers. It uses the ControlNet protocol for high-speed data transfer. The adapter supports a redundant media highway for network availability. You can mount this unit easily on a standard DIN rail. Its design ensures stable operation in harsh factory environments.

Technical Specifications

• Brand: Allen-Bradley
• Part Number: 1794-ACNR
• Product Type: Flex I/O Redundant ControlNet Adapter
• Communication Protocol: ControlNet V 1.25
• Data Transfer Speed: 5 Mbps
• Communication Ports: Two (2) ControlNet BNC ports
• Nominal Voltage: 24 Volts DC
• Input Voltage Range: 19.2 to 31.2 Volts DC
• Power Consumption: 400 mA maximum from external 24V supply
• Power Dissipation: 4.6W maximum at 19.2V dc
• Thermal Dissipation: 15.7 BTU/hr at 19.2V dc
• Flexbus Output Current: 640 mA maximum at 5 Volts DC
• Isolation Voltage: 850 Volts DC
• Inrush Current: 23A for 2 milliseconds
• Operating Temperature: -20 to 55 °C (-4 to 131 °F)
• Non-Operating Temperature: -40 to 85 °C
• Relative Humidity: 5 to 95% non-condensing
• Operating Vibration: 5 g at 10 to 500 Hz (IEC 60068-2-6)
• Operating Shock: 30 g (IEC 60068-2-27)
• Mounting Style: DIN Rail
• Indicators: Comm A (red/green), Comm B (red/green), I/O Status (red/green)

Installation and Mounting Guide

The Allen-Bradley 1794-ACNR requires a proper enclosure for installation. This module has an open-type enclosure for protection. You must mount it on a standard DIN rail. Ensure the surrounding air temperature stays below 55 °C. Use a Safety Extra Low Voltage (SELV) power supply for compliance. The power source must meet CE Low Voltage Directives (LVD). Connect the ControlNet cable using the dual BNC ports. Use Belden RG-6/U cable for proper signal transmission. The cable size should be 3.31 mm2 (12 AWG) stranded max. Keep the module away from excessive moisture or conductive contaminants.

System Integration and Capacity

This 1794-ACNR adapter supports up to eight Flex I/O modules. You can mix discrete input and output modules freely. Analog modules and specialty modules also work with this adapter. The Flexbus carries data and power to all connected modules. The adapter sends input data to the main controller. It also receives controller commands for output modules. This structure creates a complete Flex I/O system with eight slots. The dual ControlNet ports enable a high-availability network. Each port connects to a redundant trunk line for safety.

Package Contents

• One (1) Allen-Bradley 1794-ACNR ControlNet Adapter Module
• One (1) Product Installation Instructions Sheet

Common FAQs for the 1794-ACNR

1. What is the maximum number of modules for the 1794-ACNR?

The 1794-ACNR supports up to eight Flex I/O modules. You can attach any combination of eight terminal base units. Each unit holds a separate I/O module for your system.

2. Does this adapter work with a standard ControlNet cable?

Yes, the 1794-ACNR works with Belden RG-6/U ControlNet cable. The cable must have a maximum insulation of 1.2 mm (3/64 in). The data transfer speed reaches 5 Mbps through this cable type.

3. What do the LED indicators on the 1794-ACNR show?

The module has three LED indicators for status. Comm A and Comm B show each ControlNet port's health. The I/O status LED shows the Flexbus and module communication state. Red and green colors indicate normal or fault conditions.

4. Can I use the 1794-ACNR in a very cold environment?

Yes, the 1794-ACNR operates reliably from -20 to 55 °C. For storage, the unit tolerates -40 to 85 °C. This range makes it suitable for most industrial locations. Avoid exposing the module to rapid temperature changes.

5. What power supply type is recommended for the 1794-ACNR?

Use a power supply with SELV or PELV rating for the 1794-ACNR. The supply must provide 24V DC nominal voltage. The acceptable range is 19.2 to 31.2V DC. This setup meets the CE Low Voltage Directive requirements.