Purchase now: Allen-Bradley 1756-A17 ControlLogix Chassis
Purchase now: Atlantechdrives provides you the 1756-A17, the absolute largest and most expansive industrial-grade chassis engineered by Rockwell Automation for the flagship ControlLogix 1756 programmable automation controller (PAC) platform. Measuring over 20 inches wide, this massive 17-slot chassis is designed for the most colossal, data-intensive, and highly centralized industrial control applications in the world. It provides the ultimate physical and electrical backbone for sprawling PlantPAx Distributed Control Systems (DCS), allowing engineers to house a top-tier L8 processor alongside up to 16 massive arrays of local analog I/O, digital I/O, or complex network routing bridges (such as EtherNet/IP, ControlNet, and legacy DH+) all within a single unified backplane. Constructed from rugged extruded aluminum, the 1756-A17 delivers the phenomenal structural rigidity and superior electromagnetic interference (EMI) shielding required to operate flawlessly in massive petrochemical refineries, automotive mega-factories, and continuous power generation plants.
Technical Specifications of the 1756-A17
The 1756-A17 features an incredible 17 usable module slots, numbered from 0 to 16. It operates on a high-speed multi-layer printed circuit board (PCB) that ensures microsecond data propagation from the far-right slot all the way to the processor, regardless of the immense physical width.
- Part Number: 1756-A17
- Platform: ControlLogix 1756 System
- Number of Available Slots: 17
- Mounting Type: Back-panel surface mount (horizontal orientation strictly required)
- Backplane Current Capacity (1.2V DC): 1.5 A
- Backplane Current Capacity (3.3V DC): 4 A
- Backplane Current Capacity (5.1V DC): 15 A
- Backplane Current Capacity (24V DC): 2.8 A
Expert Tips: The Limits of Centralized I/O Architecture
Deploying the massive 1756-A17 chassis indicates a design philosophy heavily favoring «Centralized I/O» rather than «Distributed I/O». Expert Tip: While having 17 slots in one location simplifies network topology, it creates a massive physical wiring bottleneck. If you completely fill a 17-slot chassis with 36-pin high-density I/O modules, you will have over 600 physical copper wires converging into a single location in your electrical cabinet. You must implement advanced wire management systems, utilizing deep wire ducts and multi-tier terminal blocks, to prevent the cabinet from becoming an unmaintainable «rat’s nest.» Furthermore, the total thermal load generated by 17 active industrial modules is immense. You must actively calculate the total BTU/hr heat dissipation of this fully loaded rack and ensure your enclosure is equipped with an adequately sized industrial air conditioning unit (like a Hoffman or Rittal enclosure cooler) to prevent catastrophic thermal failure of the entire PLC system.
Maintenance: Centralized Grounding and Slot Fillers
Because the 1756-A17 spans such a large physical distance, achieving a perfect, low-impedance chassis ground is more critical here than on any other rack. You must install a dedicated, heavy-gauge solid copper wire (minimum 8 AWG) from the specific grounding lug provided on the left side of the chassis directly to the central ground bus bar of the enclosure to prevent high-frequency EMI from corrupting backplane data. Additionally, if your massive rack has any empty slots, you must absolutely install 1756-N2 blank slot filler modules. In a rack this wide, leaving slots open completely destroys the internal thermal convection airflow, starving the active modules of cooling air while simultaneously exposing the sensitive gold-plated backplane pins to corrosive factory atmosphere.
Frequently Asked Questions (FAQs)
Q: What power supply is required to run a fully loaded 1756-A17 chassis?
A: Because of the massive potential power draw of 17 modules, it is almost universally required to use a high-capacity power supply, such as the 1756-PA75 (120V AC) or 1756-PB75 (24V DC). Standard capacity supplies will likely fail to boot a fully loaded 17-slot rack.
Q: Can I use this chassis to build a redundant ControlLogix system?
A: Yes, but with strict limitations. In a standard ControlLogix redundancy architecture, the primary and secondary chassis typically only contain the Power Supply, CPU, Redundancy Module, and Network Bridges. A massive 17-slot rack is rarely used for the redundant pair itself; it is more commonly deployed as the massive remote I/O rack that the redundant controllers talk to.
Do you need more references from this brand? Explore our full catalog of Allen-Bradley here.
As the largest available rack, the 1756-A17 supports high-density I/O configurations alongside a ControlLogix 5573 processor.
