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Description
Application Scenarios:
A municipal water treatment plant had run the same SLC 5/04 on its filter backwash sequence for over nineteen years. The original 1746-A10 chassis was full — every slot populated — and a new set of valve position feedback points from a third filter train had nowhere to land. The plant faced a choice that is familiar to anyone maintaining installed SLC 500 base: rip out a working, validated control system and migrate to CompactLogix, or expand what was already there. A full migration meant re-validating the backwash sequence, re-commissioning, retraining operators, and absorbing a multi-week outage on a process that could not be taken offline during wet weather season.The expansion route won. A second 1746-A7 chassis was mounted in the same enclosure column, and a 1746-C9 linked it to the local chassis. Because the cable carries backplane data and DC power in one assembly, the expansion rack needed only its own 1746-P power supply — no additional communication module, no configuration in RSLogix 500 beyond what the SLC automatically recognizes, and no change to the existing ladder logic addressing for the original ten slots. The new valve feedback points simply appeared as additional I/O in the same logical image. The plant added capacity in a single shift instead of a multi-week migration, at a fraction of the cost, with the original validated program untouched.This is precisely the role the 1746-C9 plays across the installed base: it is the difference between a 300 expansion and a 50,000 migration. It matters most in water and wastewater, packaging machines, material handling, aggregate and cement plants, food and beverage lines, and older automotive sub-assembly cells — anywhere a SLC 500 has been running reliably for two decades and the requirement is to add I/O rather than replace the platform. It also serves as the critical spare: when a legacy panel loses its expansion rack to a damaged cable, the 1746-C9 is the part that restores production in minutes rather than days.
Parameter:
| Main Parameters | Value/Description |
|---|---|
| Product Model | 1746-C9 |
| Manufacturer | Allen-Bradley (Rockwell Automation) |
| Product Category | Chassis / Rack Interconnect Cable (SLC 500 backplane expansion accessory) |
| Cable Length | 914.4 mm (36 in. / 3 ft) — the mid-range option in the 1746-C series, suited to vertically stacked chassis in one enclosure |
| Compatible Chassis | 1746-A4 (4-slot), 1746-A7 (7-slot), 1746-A10 (10-slot), 1746-A13 (13-slot), in any combination |
| Connector Type | Multi-pin high-density ribbon bus connectors at both ends, 50-pin (2 × 25) class, with locking tabs and rigid shrink-wrap strain relief |
| Keying Design | Opposite key orientation at each end — key on the outside of the connector at one end, inside at the other — making reversed or cross insertion mechanically impossible |
| Signal Carried | Parallel backplane communication bus plus system DC power (logic and backplane supply) between local and expansion chassis |
| Backplane Current Rating | 110 mA at 5V DC; 85 mA at 24V DC — the budget consumed per slot when calculating expansion power headroom |
| Shielding | Fully shielded ribbon construction for EMI resistance in cabinets containing drives, contactors, and motor starters |
| Wiring Conductor | 22 AWG stranded copper, industrial PVC jacket resistant to oil and abrasion |
| Recommended Chassis Spacing | 152.4 mm (6 in.) to 914.4 mm (36 in.); maintain maximum 127 mm (5 in.) separation when stacking two 1746-A13 chassis |
| Clearance Requirement | Minimum 101.6 mm (4 in.) clearance at the side of the chassis to accommodate the required cable bend radius |
| Maximum System Expansion | Up to three chassis total (one local plus two expansion), requiring two interconnect cables |
| Operating Temperature | -20 °C to +60 °C (some documentation cites up to +75 °C; refer to the original manual for your installation) |
| Installation Orientation | Cable must exit the right-hand side of the chassis containing the CPU; reverse routing is an incorrect installation |
| Weight | Approx. 0.03–0.16 kg depending on packaging reference; Rockwell lists 0.352 kg shipping weight |
| Certifications | UL, CSA, CE — suitable for industrial control panels in North American and European markets |
| Connection Hardware | Uses 1746-RT32 connection hardware family |
| Installation Document | Rockwell publication 1746-IN029 (Rack Interconnect Cables, catalog numbers 1746-C7, 1746-C9, 1746-C16) |
| Lifecycle Status | Discontinued by Rockwell Automation as of December 31, 2022; no planned direct replacement — available through surplus, refurbished, and new-old-stock channels |
| Country of Origin | China; UPC 662073521624 |
