Introduction
Industry has evolved from hardwired relay panels to smart distributed I/O, and network uptime now decides plant profitability. The Allen-Bradley 1794-ACNR15 Redundant ControlNet Adapter Module protects that uptime. As a Flex I/O communication adapter, it links a ControlNet network to as many as eight Flex I/O modules. Dual ControlNet BNC ports let you build a redundant data highway, so a single trunk failure does not stop production.
Why the 1794-ACNR15 Belongs in Your Upgrade Plan
This adapter is a direct replacement for aging Flex I/O ControlNet adapters. It keeps your existing chassis, wiring, and I/O modules in service while restoring network redundancy. You avoid a full platform migration, and you regain the fault tolerance that modern production demands.
Redundancy That Protects Output
Two ControlNet BNC ports connect to separate trunks. When one trunk fails, data automatically routes to the second trunk. The 1794-ACNR15 supports a 5 Mbps data transfer speed and ControlNet protocol V 1.25. Front-panel LEDs for Comm A, Comm B, and I/O status give technicians fast visual confirmation of network health.
Power and Electrical Profile
The module runs from an external 24V DC supply. The input voltage range is 19.2-31.2V DC, and power consumption is 400 mA maximum. Isolation voltage is 850V DC, and inrush current is 23A for 2ms. Flexbus output current reaches 640 mA maximum. Power dissipation is 3.4W maximum at 19.2V DC, with thermal dissipation of 15.7 BTU/hr at 19.2V DC.
Environmental Durability
The 1794-ACNR15 operates from -20 to 55 °C (-4 to 131 °F). It withstands 5 g vibration at 10-500 Hz and 30 g operating shock. The surrounding temperature limit is 55 °C (131 °F). These ratings suit control cabinets in manufacturing, process, and utility environments.
Technical Specifications
| Specification | Value |
|---|---|
| Product Description | Redundant ControlNet Adapter Module |
| Communication Port | Two (2) ControlNet BNC |
| Data Transfer Speed | 5 Mbps |
| ControlNet Protocol | V 1.25 |
| Input Voltage Range | 19.2-31.2V DC |
| Power Consumption | 400 mA maximum from external 24V supply |
| Flexbus Output Current | 640 mA max. |
| Isolation Voltage | 850V DC |
| Inrush Current | 23A for 2ms |
| Mounting | DIN Rail |
| Operating Temperature | -20…55 °C (-4…131 °F) |
| Vibration | 5 g @ 10…500 Hz |
| Operating Shock | 30 g |
| Indicators | Comm A: red/grn, Comm B: red/grn, I/O status: red/grn |
Installation and Commissioning
Mount the adapter on a DIN rail inside a protective enclosure. Connect the external 24V DC supply within the 19.2-31.2V DC range. Use ControlNet cable rated 3.31 mm² (12 AWG) stranded maximum with 1.2 mm (3/64 in.) maximum insulation. For power connections, use 0.33-2.5 mm² (22-12 AWG) solid or stranded copper wire with 75 °C (167 °F) or greater insulation rating. For double wire connections, use 0.33-1.3 mm² (22-16 AWG) wire that is not intermixed. Observe the 7 pound-inches torque requirement during mounting. Confirm LED behavior after power-up before enabling the network.
Compatibility and Integration
The 1794-ACNR15 works within the Flex I/O family and supports up to eight Flex I/O modules in any combination. It communicates over ControlNet at 5 Mbps using protocol V 1.25. If your system uses redundant ControlNet media, this adapter is the interface that connects the trunk to the I/O rack.
Maintenance and Reliability
Inspect the adapter periodically for loose connections, LED faults, and dust buildup. Keep the enclosure within the specified temperature range and avoid vibration beyond the rated 5 g at 10-500 Hz. Follow the manufacturer’s safety manual for all service work. Because the 1794-ACNR15 preserves your existing Flex I/O investment, it delivers strong return on investment compared with a full network replacement.
Buyer’s Checklist
Before ordering, verify your ControlNet trunk layout, supply voltage, and Flex I/O module count. Confirm that your enclosure meets the operating temperature and shock requirements. SpareTechPLC supplies the 1794-ACNR15 and can help you confirm compatibility with your existing Flex I/O system. Please verify current lifecycle status and availability with SpareTechPLC before ordering.
Frequently Asked Questions
Q: How many Flex I/O modules can the 1794-ACNR15 support?
A: It supports up to eight Flex I/O modules in any combination.
Q: What is the data transfer speed of this adapter?
A: The 1794-ACNR15 transfers data at 5 Mbps over ControlNet.
Q: What power supply does the 1794-ACNR15 require?
A: It requires an external 24V DC supply with an input voltage range of 19.2-31.2V DC and 400 mA maximum current.
Q: How does the redundant ControlNet feature work?
A: Two ControlNet BNC ports connect to separate trunks. If one trunk fails, data automatically routes to the second trunk.
Q: What are the operating temperature limits?
A: The module operates from -20 to 55 °C (-4 to 131 °F).
