Allen Bradley 1746-A4 SLC 500 4-Slot Modular Backplane Chassis

Product Overview

The Allen Bradley 1746-A4 functions as a rugged, 4-slot modular chassis for the legacy SLC 500 controller platform. This backplane assembly serves as the physical foundation and electrical backbone for a complete automation assembly, securely housing the primary SLC 5/0x processor, the system power supply, and standard digital, analog, or specialty I/O modules. It distributes local operational power and coordinates data signaling across the internal bus. We guarantee this unit arrives in 100% brand new, original factory-sealed condition.

Technical Specifications

Engineering Advantages

• High-Speed Bus Signal Integrity: The heavy-duty 1746 backplane traces deliver clean 5.1V DC and 24V DC power rails across all slots while maintaining stable cross-talk isolation. This high level of shielding prevents high-frequency data corruption when routing complex analog or communication signals adjacent to high-draw digital switching cards.

• Compact Footprint for Small Enclosures: The 4-slot frame configuration optimizes tight panel space. This compact size allows engineering teams to install dedicated remote I/O drops, localized pump control panels, or small skid systems without dedicating excess enclosure real estate to unused chassis slots.

• Rigid Multi-Chassis Expansion Path: The integrated side connection port supports standard 1746 chassis expansion cables. This port allows engineers to link up to 3 individual racks together horizontally or vertically, scaling the local I/O capacity up to meet growing machine requirements without swapping out the primary CPU.

• Direct Panel-Ground Structural Stability: The chassis framework features robust, integrated panel-mounting tabs that anchor the assembly directly to the metal enclosure backplate. This mechanical layout ensures an immediate, low-impedance grounding path, which significantly dampens the effects of industrial cabinet vibration and nearby electromagnetic noise.

FAQs

• Does this 1746-A4 chassis arrive in original Allen Bradley packaging?

  Yes. We ship this chassis rack as a 100% brand new, authentic factory item inside its original Rockwell Automation box. It includes the original cardboard supports, anti-static plastic barrier, and factory instruction sheets intact.

• Does the 4-slot count include the space for the power supply module?

  No. The dedicated power supply slot sits on the far left side of the chassis frame and utilizes its own mounting footprint. The 4 slots refer specifically to the standard module openings available to hold the CPU (Slot 0) and your chosen combination of I/O or communication modules.

• How many expansion racks can I chain to this primary 1746-A4 assembly?

  The 1746 backplane architecture allows you to link a maximum of 3 chassis together into a single local system. You must utilize official 1746-C7, 1746-C9, or 1746-C11 interconnect cables to run the backplane communications safely between the separate racks.

• What are the installation grounding requirements for this chassis?

  You must clear all non-conductive paint or coatings away from the enclosure backplate at the screw contact points. Fasten the 1746-A4 securely using star washers to ensure a solid, direct metal-to-metal panel ground connection for effective electrical noise dissipation.