Description
The Allen-Bradley 1794-ACN15 is a ControlNet communication adapter module for the FLEX I/O platform. It functions as a gateway, interface, and power supply regulator between a ControlNet network and up to eight FLEX I/O modules on a single backplane. Operating at a nominal 24 V DC input, this module manages the deterministic transmission of critical real-time I/O data and explicit messaging across industrial automation networks.
Technical Specifications
| Parameter | Value / Specification |
| Model Number | 1794-ACN15 |
| Brand | Allen-Bradley / Rockwell Automation |
| Product Type | ControlNet Adapter Module |
| I/O Capacity | Supports up to 8 FLEX I/O modules |
| Input Voltage Range | 19.2 to 31.2 V DC (24 V DC Nominal) |
| ControlNet Communication Rate | 5 Mbps |
| FlexBus Output Current | 640 mA maximum @ 5 V DC |
| Inrush Current | 23 A for 2 ms |
| Power Dissipation | 4.6 W maximum @ 24 V DC |
| Network Media | RG-6 coax cable via BNC connectors |
| Isolation Voltage | 50 V (continuous), Basic Insulation Type, Network to System |
| Operating Temperature | −20 to +55°C (−4 to +131°F) |
| Storage Temperature | −40 to +85°C (−40 to +185°F) |
| Relative Humidity | 5 to 95% (Non-condensing) |
| Dimensions (H x W x D) | 87 x 69 x 69 mm (3.4 x 2.7 x 2.7 in.) |
| Standards Compliance | UL, CSA, CE, C-Tick, Ex (Zone 2) |
Commercial and Logistics Terms
- Condition: New Original (New Surplus) or Refurbished (tested) available
- Warranty: 12-Month Comprehensive Warranty
- Availability: In Stock
- Lead Time: Ships within 1 to 2 business days from order confirmation
- Pricing: Price subject to market conditions; contact us for a firm quote
Engineering Overview & Integration Notes
In legacy and hybrid modern industrial architectures, the 1794-ACN15 bridges physical I/O instrumentation with Logix5000 (ControlLogix, CompactLogix) or PLC-5/SLC 500 controllers via ControlNet.
Network Address Configuration
The node address for the 1794-ACN15 is set via two rotary switches located on the top of the module. Valid node addresses range from 01 to 99. The network configuration requires RSNetWorx for ControlNet to establish the Scheduled Bandwidth (NUT – Network Update Time) and save the configuration into the active keeper file.
Power Distribution and FlexBus Limits
The adapter provides up to 640 mA of current at 5 V DC to the internal FlexBus backplane. Engineers must perform a power budget calculation by summing the internal bus current draw of all eight connected I/O modules. Exceeding 640 mA will cause unstable behavior, communication dropouts, or an adapter shutdown.
Field Note: The 1794-ACN15 features dual BNC network connectors (Channel A and Channel B) to support redundant media configurations. If media redundancy is not implemented, connect the primary trunk line to Channel A. Do not leave Channel B unprotected in harsh environments; use a dust cap if it is unpopulated.
Frequently Asked Questions
What is the difference between the 1794-ACN15 and the 1794-ACNR15?
The 1794-ACN15 supports both non-redundant and true media redundant network Topologies via its dual BNC ports. However, the 1794-ACNR15 specifically designates specialized logic for automated medium-switching diagnostics. In practical applications, the 1794-ACN15 is often deployed as a direct drop-in replacement or alternative depending on your active RSNetWorx configuration file and keeper settings.
Can this adapter be swapped out while the system is powered on (RIUP)?
Yes, the 1794-ACN15 supports Removal and Insertion Under Power (RIUP) for the adapter module itself and the adjacent I/O modules, provided the area is known to be non-hazardous. However, disconnecting the active ControlNet BNC taps will break the token-passing network loop and may affect downstream nodes.
How do I troubleshoot a flashing red “STAT” LED?
A flashing red Status (STAT) LED generally indicates an incorrect or unconfigured node address, or a mismatch between the physical hardware layout and the I/O configuration compiled in RSLogix 5000 / Studio 5000. Verify that the rotary dials match the exact slot mapping in your controller’s I/O tree and re-schedule the network using RSNetWorx.
