Product Overview
The Allen-Bradley 1734-MB is the standard mounting base (carrier) for Rockwell Automation’s 1734 POINT I/O™ series, serving as the fundamental mechanical and electrical foundation upon which all 1734 I/O modules, adapters, and specialty modules are installed. Although the Allen-Bradley 1734-MB has been designated as a legacy product and is officially superseded by the 1734-MB2, it remains widely used in existing installed bases and is fully functional with the entire 1734 family when paired with the appropriate removable terminal block (RTB). The base provides the POINTBus™ backplane communication pathway and distributes both I/O power and logic power from the terminal block to the mounted module, ensuring deterministic data exchange between the field device and the EtherNet/IP, DeviceNet, or ControlNet adapter residing on the same POINT I/O rack.Each Allen-Bradley 1734-MB features an integrated five-position orange mechanical keying mechanism that can be set to match the specific I/O type being installed, preventing incorrect module substitution during maintenance—a critical safeguard in high-availability systems. Bases are designed to interlock laterally, allowing multiple Allen-Bradley 1734-MB units to be snapped together side-by-side on a standard 35 mm DIN rail, forming a compact, scalable distributed I/O node that can be panel- or machine-mounted close to sensors and actuators. The base itself carries no active electronics but is essential for establishing the module’s physical seating, electrical continuity, and wiring access via the pluggable 1734-RTB (screw-clamp) or 1734-RTBS (spring-clamp) terminal blocks.Constructed from flame-retardant thermoplastic rated to UL 94 V-0 and suitable for IP20 environments, the Allen-Bradley 1734-MB delivers a low-cost, reliable infrastructure component for building flexible POINT I/O assemblies in both new machinery designs and retrofit projects where the original footprint must be preserved.
Technical Specifications
Product Model | 1734-MBManufacturer | Rockwell Automation / Allen-BradleyProduct Type | POINT I/O Standard Mounting Base (Carrier)Series | Allen-Bradley 1734 POINT I/OCompatible Modules | All 1734 POINT I/O modules (digital, analog, temperature, specialty, adapters)Required Accessory | Removable Terminal Block: 1734-RTB (screw) or 1734-RTBS (spring)Backplane Bus | POINTBus (proprietary serial backplane via gold-finger connector)Mechanical Keying | 5-position adjustable orange keying pins (module-specific)Mounting Method | 35 mm × 7.5 mm / 15 mm DIN rail (EN 60715), snap-fitEnclosure Rating | IP20 (when installed in appropriate enclosure)Operating Temperature | -20 °C to +60 °C (-4 °F to +140 °F)Storage Temperature | -40 °C to +85 °CHumidity (non-condensing) | 5 % to 95 % RHDimensions (H × W × D) | approx. 91 mm × 30 mm × 94 mm (3.58″ × 1.18″ × 3.70″)Weight | approx. 0.06 kg (0.13 lb)Material | Flame-retardant thermoplastic, UL 94 V-0Agency Approvals | CE, UL Listed, cULus, KC, ATEX (system dependent)Legacy Status | Discontinued – functional replacement is 1734-MB2
Main Features and Advantages
The Allen-Bradley 1734-MB provides the essential carrier infrastructure that makes the 1734 POINT I/O system one of the most flexible distributed I/O platforms in the industry. Its side-interlocking design allows an unlimited number of Allen-Bradley 1734-MB bases to be joined mechanically, creating a continuous I/O bank that can be cut to length on the DIN rail without special end plates or termination bars. This modularity lets panel builders right-size each I/O node—adding only as many slots as needed—then close the system with a terminal base or end cap.A standout protective feature is the five-position mechanical keying system built into every Allen-Bradley 1734-MB. By setting the orange keys to match the key code of the intended I/O module, technicians are physically prevented from inserting an incompatible module type (e.g., a 120 V AC input in place of a 24 V DC input). This simple but effective safeguard reduces human error during field replacements and helps maintain system integrity in regulated industries.The Allen-Bradley 1734-MB also supports hot-module insertion when used with a properly powered adapter and RTB—meaning a module can be replaced while the remainder of the POINT I/O rack continues scanning, minimizing downtime. Because the base has no active circuitry, it is immune to firmware obsolescence concerns; existing Allen-Bradley 1734-MB units remain viable indefinitely provided they are mechanically sound. Where new procurement is required, the electrically and mechanically interchangeable 1734-MB2 is the drop-in successor offering identical footprint and function.Compact width (30 mm per base) maximizes DIN-rail real estate in crowded panels, and the ability to mix screw-type and spring-clamp terminal blocks on different slots in the same rack accommodates installer preference or wire-type requirements. Overall, the Allen-Bradley 1734-MB delivers dependable, low-profile, and cost-effective mounting for mission-critical I/O in machine control, process skids, and building automation applications.
Application Field
The Allen-Bradley 1734-MB is used wherever Rockwell Automation 1734 POINT I/O is deployed—which spans virtually every sector that utilizes ControlLogix®, CompactLogix™, or Micro800® controllers. In discrete manufacturing, the Allen-Bradley 1734-MB forms the backbone of distributed I/O drops on packaging lines, assembly cells, and material handling conveyors, allowing sensors and actuators to be wired locally at the machine rather than back to a central cabinet, thereby reducing wiring cost and troubleshooting time.In process and hybrid industries, the Allen-Bradley 1734-MB hosts analog input modules reading 4–20 mA transmitter loops from tank level or flow meters, and analog output modules driving control valves—all communicating back to the control room via an EtherNet/IP adapter on the same POINT I/O rail. OEMs of custom machinery (compressors, injectors, test stands) specify the Allen-Bradley 1734-MB because it lets them offer customers a compact, brand-recognized I/O architecture that integrates seamlessly into enterprise-level Rockwell control networks.Even in retrofit scenarios where an older panel originally contained the Allen-Bradley 1734-MB, spare bases or complete racks can be sourced to maintain continuity without rewiring the entire enclosure. For any application requiring a small-footprint, modular, and keyed I/O carrier compatible with the world’s most widely adopted industrial Ethernet I/O platform, the Allen-Bradley 1734-MB—or its 1734-MB2 equivalent—remains the correct foundational component.
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