Allen-Bradley 1734-ACNR Replacement for POINT I/O ControlNet

Product Overview

Allen-Bradley 1734-ACNR Replacement for POINT I/O ControlNet: Seamless Migration & Smooth Transition

When your legacy ControlNet infrastructure reaches end-of-life or a critical 1734-ACNR adapter fails in the field, every hour of unplanned downtime translates directly into production loss. The Allen-Bradley 1734-ACNR is a POINT I/O ControlNet redundant media network adapter designed for Rockwell Automation ControlNet architectures. It provides dual-port redundant coaxial media connectivity, enabling fault-tolerant communication between the ControlNet network and distributed POINT I/O modules mounted on a 1734 series mounting base.

At TOPNLMS, we stock verified 1734-ACNR units sourced from authorized supply chains, pre-tested before dispatch, and backed by a 12-month replacement warranty. Whether you are executing a planned upgrade, responding to an emergency failure, or building a retrofit bill of materials for a modernization project, this page provides the technical and procurement information you need to move forward with confidence.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful 1734-ACNR migration rarely involves a single component. In practice, field engineers replacing a failed or end-of-life ControlNet adapter must also audit the surrounding system to ensure every layer of the architecture supports the transition without introducing new failure points.

The 1734-ACNR mounts on a 1734-TB or 1734-TBS terminal base, which provides the mechanical locking and backplane power connection. If the terminal base shows signs of wear, discoloration, or damaged locking tabs after years of service, replacing it alongside the adapter eliminates a common source of intermittent backplane faults. The POINT I/O digital and analog modules — such as the 1734-IB8 8-channel DC input module and the 1734-OB8 8-channel DC output module — remain fully compatible with the 1734-ACNR and do not require re-wiring when the adapter is swapped on the same mounting base assembly.

On the ControlNet network side, the 1734-ACNR connects via BNC coaxial cable to the ControlNet trunk. If your plant is running a 1786-RPA/B ControlNet repeater or a 1786-RPCD coaxial tap at the drop point, verify that the tap impedance and cable segment length remain within ControlNet specification after the adapter replacement. For systems where the upstream controller is a 1756-CNB or 1756-CNBR ControlNet bridge module installed in a ControlLogix 1756 chassis, the scheduled connection parameters configured in RSNetWorx for ControlNet must be re-verified and re-downloaded after the node is replaced, even if the node address rotary switch is set identically to the previous unit.

Plants that are simultaneously modernizing their HMI layer often pair this adapter replacement with a PanelView Plus 7 terminal upgrade, moving away from older PanelView 550 or PanelView 900 units that communicated over ControlNet. In such cases, the 1734-ACNR continues to serve the I/O layer while the HMI migrates to EtherNet/IP, a common hybrid architecture during phased modernization programs. Similarly, if the project scope includes replacing an aging SLC 5/05 or PLC-5/20C controller with a ControlLogix L7x platform, the existing POINT I/O drops connected via 1734-ACNR adapters can be retained during the transition period, reducing the scope and risk of the cutover.

For sites where power supply reliability is a concern, the 1734-EP24DC POINT I/O power supply expander can be added to the mounting base assembly to extend backplane power capacity when the I/O count grows beyond the base adapter’s power budget. Pairing this with a 1606-XLP power supply on the 24 VDC rail ensures stable field-side power during and after the retrofit.

Retrofit Guidance FAQ

Q: Can I replace the 1734-ACNR without re-wiring the I/O modules?
A: Yes. The 1734-ACNR mounts on the terminal base and connects to the backplane. The field wiring terminates on the individual I/O module terminal bases, not on the adapter itself. Replacing the adapter does not require disturbing any field wiring on the I/O modules downstream.

Q: Do I need to re-schedule the ControlNet network after replacing the adapter?
A: Yes. ControlNet is a scheduled network. After replacing the 1734-ACNR, you must open RSNetWorx for ControlNet, verify the node appears at the correct address, and download the schedule to the network. Failure to do so will result in the controller reporting a connection fault for the I/O drop.

Q: Is the 1734-ACNR physically interchangeable with the 1734-ACNR15?
A: The 1734-ACNR and 1734-ACNR15 share the same 1734 mounting base footprint and BNC coaxial media connections. Verify the firmware revision compatibility with your RSNetWorx version before installation. In most cases, the replacement is direct.

Q: What is the maximum number of I/O modules supported per 1734-ACNR adapter?
A: The 1734-ACNR supports up to 63 POINT I/O modules per adapter node, subject to backplane power budget constraints. Use the 1734-EP24DC power expander if the module count approaches the power limit.

Q: Can the 1734-ACNR coexist with EtherNet/IP adapters (1734-AENT) in the same control cabinet?
A: Yes. Different POINT I/O drops in the same cabinet can use different network adapters. The 1734-ACNR and 1734-AENT are independent nodes on their respective networks and do not interfere with each other physically or electrically when mounted in separate base assemblies.

Q: What programming software is required to configure the 1734-ACNR?
A: RSLogix 5000 (or Studio 5000 Logix Designer) is used to configure the I/O tree and connection parameters. RSNetWorx for ControlNet is required to schedule the ControlNet network. No additional firmware tools are required for standard replacement.

Warranty Assurance

Every 1734-ACNR unit shipped by TOPNLMS is covered by a 12-month replacement warranty from the date of delivery. Before dispatch, each unit undergoes a functional verification check including backplane communication test and BNC port integrity inspection. If a unit is found to be defective on arrival or fails within the warranty period under normal operating conditions, we will arrange a replacement shipment at no additional cost.

Our after-sales response target is within 24 hours on business days. For urgent plant-down situations, please contact us directly by phone to expedite processing. We maintain buffer stock of high-demand POINT I/O components to support emergency replacement orders with same-day or next-day dispatch from our Xiamen warehouse.

Procurement documentation including test reports, packing lists, and commercial invoices is provided with every order to support your incoming inspection and asset management processes. We accept purchase orders from industrial end-users, system integrators, and MRO procurement teams.