Allen-Bradley 1794-ACNR15 Redundant ControlNet Module

Overview – 1794-ACNR15 Redundant ControlNet Adapter

• 1794-ACNR15 is a redundant media ControlNet adapter from Allen‑Bradley.
• Part of the Flex I/O family for distributed I/O in industrial networks.
• Supports dual ControlNet trunks for automatic failover.
• Handles up to eight (8) Flex I/O modules in any combination.
• ControlNet protocol version 1.5, data rate 5 Mbps.

Key Technical Data

• Brand: Allen‑Bradley / Rockwell Automation
• Catalog No.: 1794-ACNR15
• Type: Redundant ControlNet Communication Adapter
• Ports: Two BNC (Comm A & Comm B)
• Speed: 5 Mbps
• Voltage: 24V DC (range 19.2…31.2V DC)
• Current Draw: 450 mA max
• Power Dissipation: 3.4 W @ 19.2V DC
• Thermal Dissipation: 15.7 BTU/hr
• Isolation Voltage: 850V DC
• Inrush Current: 23A for 2ms
• Flexbus Output: 640 mA max
• Mounting: DIN rail (torque 7 lb‑in)
• Dimensions: 87 x 94 x 69 mm
• Weight: 220 g (7.76 oz)

Environmental & Operating Limits

• Operating Temperature: -20…55 °C (-4…131 °F)
• Surrounding Air Temp: 55 °C (131 °F) max
• Humidity: 5…95 % non‑condensing
• Vibration (operating): 5 g @ 10…500 Hz (IEC 60068‑2‑6)
• Shock (operating): 30 g (IEC 60068‑2‑27)
• Non‑operating shock: 50 g
• Enclosure: Open‑style, IP20
• Temperature Code: T4

Wiring & Power Connections

• Wire size (solid/stranded): 0.33…2.5 mm² (22…12 AWG)
• Insulation rating: 75 °C (167 °F) or greater
• Max insulation thickness: 1.2 mm (3/64 in.)
• Double wire (stranded): 0.33…1.3 mm² (22…16 AWG)
• External 24V supply required (400 mA typical).

Diagnostics & Status LEDs

• Comm A (red/green) – ControlNet port A status
• Comm B (red/green) – ControlNet port B status
• I/O Status (red/green) – module and bus health
• LEDs provide real‑time fault and operation feedback.

Compatibility – Suitable For

• Flex I/O chassis (any mix of 8 I/O modules)
• ControlNet networks requiring redundant media
• Distributed I/O applications in process & factory automation
• Rockwell Logix controllers via ControlNet
• Upgrading existing 1794‑ACN or ACNR systems

Oiltech Controls’s Insight

• This adapter excels in high‑availability plants where network uptime is critical.
• Dual BNC ports enable seamless trunk switching without PLC program changes.
• Commonly used with 1794‑IB16, 1794‑OB16, 1794‑IE8, and 1794‑OW8 modules.
• We recommend pairing with Belden 1502‑type cables for optimal signal integrity.

Professional FAQ – 5 Expert Questions

Q1: Can I mix analog and digital Flex I/O modules behind this adapter?

Yes. The 1794‑ACNR15 supports any combination of up to eight Flex I/O modules, regardless of type. However, total Flexbus current (640 mA max) must be respected.

Q2: What is the real benefit of redundant media on ControlNet?

Redundant trunks eliminate a single point of failure. If the primary BNC trunk is damaged, the adapter auto‑switches to the secondary trunk. This is vital for critical processes like refinery or turbine control.

Q3: How do I choose between 1794‑ACN15 and 1794‑ACNR15?

Choose ACNR15 if you have or plan to install two ControlNet trunks. For single‑trunk networks, the ACN15 is sufficient. ACNR15 adds cost but provides redundancy – we often advise it for SIL‑related loops.

Q4: What is the maximum cable length for the BNC ports?

ControlNet BNC segments are limited to 1000 m (3280 ft) per trunk using RG‑6 quad‑shield cable. Use repeaters for longer distances.

Q5: Does this module support 1794‑FLEX I/O with twisted‑pair only?

Yes. The 1794‑ACNR15 uses standard BNC connectors. You can connect to both twinax and coax trunks. We recommend using Belden 1502A or equivalent.

Why Buy From Oiltech Controls?

• 15+ years supplying industrial automation spares
• Global logistics – FedEx, UPS, DHL with 24‑28h dispatch
• Pre‑shipment testing of surplus and refurbished units
• 12‑month warranty against defects
• Expert support for obsolete and legacy control systems

Contact: info@oiltechcontrols.com  |  +86 158 8020 0923 (WhatsApp)

Shipping: FedEx, UPS, DHL – worldwide express. Orders ship within 24‑28 hours.

Warranty: 12 months from shipment date. Covers manufacturing and performance issues.

Package includes: 1794‑ACNR15 module, two BNC connectors, DIN rail mounting hardware.

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