Allen-Bradley 1734-IR2 Replacement for POINT I/O Series

Product Overview

Allen-Bradley 1734-IR2 Replacement for POINT I/O Series: Seamless Transition from Legacy RTD Systems

The Allen-Bradley 1734-IR2 is a 2-channel RTD/Resistance Input Module designed for the POINT I/O 1734 series platform — one of the most widely deployed distributed I/O architectures in process and discrete manufacturing environments. Whether your facility is migrating from an aging SLC 500 or PLC-5 control system, retiring a legacy 1771 I/O rack, or simply replacing a failed module in an existing ControlLogix or CompactLogix application, the 1734-IR2 delivers a direct, field-proven upgrade path with minimal engineering overhead.

At TOPNLMS, we maintain ready stock of the 1734-IR2 to support urgent replacement scenarios. Each unit is sourced from authorized supply chains, individually inspected prior to dispatch, and backed by a 12-month warranty. Orders placed before cut-off ship the same business day from our Xiamen warehouse, with DHL Express and FedEx International Priority options available for time-critical plant shutdowns.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful migration from a legacy RTD measurement system to the 1734-IR2 rarely involves a single module swap. In practice, the upgrade touches several interconnected components across the control cabinet and network architecture. Understanding the full bill of materials helps procurement teams plan accurately and avoid costly mid-project delays.

The 1734-IR2 operates as a slice within the POINT I/O system and requires a compatible adapter to communicate with the controller. The 1734-AENTR (dual-port EtherNet/IP adapter with Device Level Ring support) is the preferred choice for new installations requiring network redundancy, while the single-port 1734-AENT remains a cost-effective option for standard topologies. Both adapters connect the POINT I/O node to a ControlLogix or CompactLogix controller over standard EtherNet/IP, eliminating the need for proprietary backplane cabling used in older 1771 or 1746 racks.

On the power side, the POINT I/O rail requires a dedicated field-side power supply. The 1734-EP24DC provides 24 VDC field power to I/O modules on the rail and is typically installed at the beginning of each power group. For larger nodes with mixed digital and analog slices — such as combining the 1734-IR2 with 1734-IE2C current input modules or 1734-OE2C analog output modules — additional power supplies may be required depending on total current draw calculations.

Wiring the 1734-IR2 is straightforward using the removable terminal block (RTB) supplied with the module. Engineers migrating from 3-wire PT100 sensors previously wired to a 1746-NR4 will find the terminal assignments familiar, though the compact form factor of the POINT I/O slice reduces panel space requirements significantly. Signal isolation between channels is maintained internally, making the 1734-IR2 suitable for applications where sensor ground loops were previously a concern with older analog input cards.

For facilities running mixed I/O architectures — for example, retaining some legacy 1746-IB16 digital input cards while modernizing the analog measurement layer — the POINT I/O platform integrates cleanly alongside existing CompactLogix local I/O. The controller’s I/O tree in Studio 5000 Logix Designer accommodates both local and remote POINT I/O nodes simultaneously, and the 1734-IR2’s Add-On Profile (AOP) simplifies tag configuration and channel scaling without manual data table mapping.

Communication protocol compatibility is a key advantage of this migration path. Unlike legacy serial-based I/O networks (DH+, Remote I/O), the EtherNet/IP backbone used by the POINT I/O system supports standard TCP/IP infrastructure, enabling integration with SCADA systems, historian platforms, and MES layers without additional protocol converters. If the existing plant network uses managed switches, the 1734-AENTR‘s DLR capability provides fault-tolerant ring topology without additional hardware.

For temperature measurement applications requiring higher channel density, the 1734-IR2 can be deployed alongside 1734-IT2I thermocouple input modules on the same POINT I/O rail, sharing the same adapter and power infrastructure. This mixed-sensor approach is common in boiler control, HVAC, and food processing upgrade projects where both RTD and thermocouple sensors coexist in the same control zone.

Retrofit Guidance FAQ

Q: Can I reuse existing 3-wire PT100 sensor wiring from my 1746-NR4 installation?
A: Yes. The 1734-IR2 supports 2-wire, 3-wire, and 4-wire RTD configurations. Existing 3-wire PT100 field wiring can be connected directly to the 1734-IR2 RTB without re-pulling cables, provided wire gauge is within the module’s terminal specification (0.2–1.5 mm²).

Q: Do I need to rewrite my existing ladder logic program?
A: Partial revision is required. The 1734-IR2 uses EtherNet/IP implicit messaging and presents data as produced/consumed tags in Studio 5000. Legacy RSLogix 500 programs using N7/F8 file-based addressing must be remapped to controller-scoped tags. The AOP automates most of the tag structure, significantly reducing engineering time compared to manual I/O mapping.

Q: Is the 1734-IR2 compatible with my existing ControlLogix L7x controller?
A: Yes. The 1734-IR2 is fully compatible with all ControlLogix L6x and L7x series controllers, as well as CompactLogix L3x and L4x platforms, when accessed via a 1734-AENT or 1734-AENTR adapter. Firmware revision of the adapter should be verified against the controller’s Studio 5000 version for AOP compatibility.

Q: How much DIN rail space does the 1734-IR2 require compared to a 1746-NR4 rack card?
A: The 1734-IR2 occupies approximately 12 mm of DIN rail width as a single POINT I/O slice, compared to a full rack slot (typically 25–35 mm card width plus rack overhead) for the 1746-NR4. For multi-channel RTD applications, the space savings are substantial — a 4-channel RTD system using two 1734-IR2 modules requires less than 30 mm of rail space.

Q: What communication protocol does the 1734-IR2 use, and is it compatible with third-party SCADA systems?
A: The 1734-IR2 communicates via EtherNet/IP through its POINT I/O adapter. EtherNet/IP is an open standard (ODVA) supported by most modern SCADA, DCS, and historian platforms including Wonderware, iFIX, Ignition, and OSIsoft PI. No proprietary drivers or protocol converters are required.

Q: Can the 1734-IR2 replace a 1771-IRT module in a PLC-5 system?
A: Not as a direct rack-mount replacement — the 1771-IRT is a 1771 backplane card and the 1734-IR2 is a POINT I/O slice. However, the 1734-IR2 is the recommended functional replacement when migrating the entire PLC-5 / 1771 I/O system to a ControlLogix or CompactLogix platform. The migration typically involves replacing the 1771 rack with a POINT I/O node and updating the control program in Studio 5000.

Warranty Assurance

Every Allen-Bradley 1734-IR2 shipped by TOPNLMS is covered by a 12-month warranty from the date of delivery. Our pre-shipment inspection process includes visual examination, label and date code verification, and functional continuity checks. Units that do not meet our quality standards are quarantined and never dispatched.

In the event of a warranty claim, our after-sales team responds within 24 business hours. Verified defective units are replaced or credited at no additional cost to the buyer. We maintain buffer stock of high-velocity POINT I/O modules specifically to support rapid warranty replacements without extended lead times.

For procurement teams managing plant maintenance budgets, TOPNLMS offers blanket order arrangements and consignment stock programs for critical spare parts including the 1734-IR2 and related POINT I/O components. Contact our technical sales team to discuss volume pricing, lead time guarantees, and approved vendor documentation requirements.

All orders include a packing list, certificate of conformance upon request, and full traceability documentation. Export compliance is handled in accordance with applicable trade regulations, with EAR99 classification applicable to standard catalog modules.

© 2026 TOPNLMS. All rights reserved.
Original Source: https://topnlms.com
Contact: [email protected] | +86 18359293191