Redundant ControlNet Adapter for Operational Cost Savings
The Allen-Bradley 1794-ACNR15 is a Redundant Media ControlNet Adapter from the Flex I/O family, designed to minimize costly downtime in distributed control systems. By providing two ControlNet BNC ports, this module automatically routes data to a secondary trunk if the primary fails, ensuring continuous operation and reducing production losses.
Technical Specifications Breakdown
Key parameters for the 1794-ACNR15 are listed below for quick reference:
| Feature | Specification |
|---|---|
| Manufacturer | Rockwell Automation |
| Brand | Allen-Bradley |
| Product Type | Redundant Media ControlNet Adapter |
| Part Number | 1794-ACNR15 |
| Communication Ports | Two (2) ControlNet BNC |
| Data Transfer Speed | 5 Mbps |
| Input Voltage Range | 19.2-31.2V DC |
| Power Consumption | 400mA maximum from external 24V supply |
| Power Dissipation | 3.4W maximum @ 19.2V dc |
| Thermal Dissipation | 15.7 BTU/hr @ 19.2V dc |
| Flexbus Output Current | 640 mA max. |
| Isolation Voltage | 850V DC |
| Inrush Current | 23A for 2ms |
| Operating Temperature | -20…55 °C (-4…131 °F) |
| Vibration | IEC 60068-2-6: 5 g @ 10…500 Hz |
| Operating Shock | IEC 60068-2-27: 30 g |
| Mounting | DIN Rail |
Industry Applications
This adapter is well-suited for process industries where redundant communication is critical. For example, in oil and gas pipelines, the dual ControlNet ports ensure data integrity even if one trunk fails, avoiding expensive shutdowns. In water treatment plants, the module's 5 Mbps speed supports real-time monitoring of distributed I/O, reducing operational overhead. The 640 mA Flexbus output current allows powering multiple I/O modules without extra supplies, lowering installation costs.
Installation & Setup Guidance
Mount the 1794-ACNR15 on a DIN rail using the provided clips. Connect each ControlNet trunk to the BNC ports labeled Comm A and Comm B. Use stranded copper wire of 3.31 mm² (12 AWG) with insulation thickness up to 1.2 mm for network cables. For external 24V DC supply, ensure voltage is within 19.2-31.2V DC and current capacity is at least 400 mA. The module supports up to eight Flex I/O modules; distribute them to balance Flexbus current draw below 640 mA.
Maintenance & Reliability
Periodically inspect the LED indicators (Comm A, Comm B, I/O status) for red signals that may indicate communication faults. Operate within the -20…55 °C temperature range to avoid thermal stress. The module's 30 g shock rating ensures reliability in high-vibration environments. No internal adjustments are required; routine checks of cable connections and power supply voltage suffice.
Compatibility & Integration
The 1794-ACNR15 uses ControlNet protocol V 1.25 and is compatible with any ControlNet network. It integrates seamlessly with Allen-Bradley Flex I/O modules and controllers supporting redundant media. The dual BNC ports allow connection to two separate ControlNet trunks for redundancy without additional hardware.
Selection Guide & Purchasing Advice
When selecting this adapter, verify that your ControlNet network uses BNC connectors and that your system requires redundant media. At SpareTechPLC, we stock the 1794-ACNR15 to help you maintain uptime. Contact our team for lifecycle status and availability before ordering.
Troubleshooting & Common Issues
If the I/O status LED is red, check that the Flexbus current does not exceed 640 mA. If Comm A or Comm B LEDs are off, verify cable connections and ensure the ControlNet trunk is active. For power issues, confirm the external supply provides 19.2-31.2V DC and at least 400 mA. Use the module's LED indicators for quick diagnostics.
Frequently Asked Questions
Q: What is the maximum number of Flex I/O modules supported?
A: The 1794-ACNR15 supports up to eight Flex I/O modules of any combination.
Q: What is the data transfer speed of this adapter?
A: It supports ControlNet transmission speed of 5 Mbps.
Q: What is the input voltage range?
A: The acceptable input voltage range is 19.2-31.2V DC, with nominal 24V DC.
Q: Does the module require an external power supply?
A: Yes, it requires an external 24V DC supply with at least 400 mA current.
Q: How does the redundancy work?
A: The module has two ControlNet BNC ports. If one trunk fails, data automatically routes to the second trunk.
