1746-c7_interconnect_cable

Description

Technical Specifications

Main Features and Advantages

Short-format design for compact enclosures: The Allen-Bradley 1746-C7​ at 6 inches is optimally sized for SLC 500 chassis mounted side-by-side on the same DIN rail or panel section, minimizing excess cable loop and simplifying wire management inside control cabinets where space is at a premium.Polarized, keyed connectors prevent mis-mating: Each end of the Allen-Bradley 1746-C7​ features a uniquely keyed 50-pin male header—one oriented for the right-side expansion port of the upstream chassis and one for the left-side port of the downstream chassis. This physical keying eliminates the risk of reversing the cable or inserting it upside-down, which would cause backplane communication failure or potential damage.Factory-terminated for signal integrity and reliability: The Allen-Bradley 1746-C7​ is manufactured to Rockwell Automation’s original SLC 500 backplane specifications with properly crimped/shielded IDC terminations and controlled conductor pairing. Using the genuine Allen-Bradley 1746-C7​ avoids the common pitfalls of user-made or generic substitute cables—such as crosstalk-induced I/O dropouts, improper shielding, or mismatched pin assignments—particularly important given the high-speed parallel backplane signaling of the SLC 500 architecture.Full backplane extension—data, addressing, and power: Unlike serial or network extension methods, the Allen-Bradley 1746-C7​ transparently extends the entire SLC 500 backplane, allowing the processor to scan expansion-rack I/O modules exactly as if they were in the base chassis. No additional configuration, addressing, or communication modules are required—simply install the cable, power up, and the I/O slots in the expansion rack become directly addressable in the controller’s I/O configuration.System scalability within SLC 500 limits: Up to three chassis total (one processor chassis + two expansion chassis) can typically be linked using the Allen-Bradley 1746-C7​ and/or longer 1746-C9 / 1746-C16 cables (depending on processor model and backplane current loading). This lets system designers scale from 4-slot to 30-slot equivalent I/O capacity using the same processor and programming environment.

Application Field

The Allen-Bradley 1746-C7​ is deployed wherever an SLC 500 modular system requires more I/O points than a single chassis can accommodate and where the additional chassis can be mounted in close physical proximity—typically within the same control enclosure or adjacent sub-panel. In discrete manufacturing cells such as packaging lines, bottling plants, and stamping presses, engineers use the Allen-Bradley 1746-C7​ to connect a second or third 1746-A7 or 1746-A10 I/O rack beside the processor rack, expanding from 16/32 I/O points to as many as 192–240 distributed I/O points under a single SLC 5/04 or 5/05 processor’s direct scan.System integrators retrofitting legacy SLC 500 panels frequently specify the Allen-Bradley 1746-C7​ when adding new digital or analog modules (1746-IB, -OW, -NIO4V, etc.) to an existing installation that has exhausted its base chassis slot count. Because the cable carries both data and backplane power, no separate I/O adapter module or external power wiring to the expansion chassis logic section is needed—only the main chassis power supply (e.g., 1746-P2, -P4) must have sufficient backplane current capacity for the added modules.In process skids and batch blending systems that still rely on SLC 500 hardware for long-term continuity, the Allen-Bradley 1746-C7​ enables compact multi-rack configurations that keep analog input modules (temperature, flow, pressure) and discrete outputs (valve drivers, pump permissives) logically unified under one controller program. For installations where racks are spaced further apart, the Allen-Bradley 1746-C7​ would be substituted by a 1746-C9 (36 in.) or 1746-C16 (50 in.), but for the majority of side-by-side rack builds the Allen-Bradley 1746-C7​ remains the standard, cost-effective choice.