Allen-Bradley 1756-A4 ControlLogix PLC Chassis

The Allen-Bradley 1756-A4 ControlLogix chassis is a four-slot backplane enclosure in the ControlLogix family designed to host 1756-series I/O and control modules. It provides four slots for mounting modules and relies on a separate ControlLogix power supply to feed the backplane; the chassis itself does not include a power supply. An electronic keying option is available to ensure module compatibility. External dimensions are approximately 20 in by 20 in by 8 in, enabling compact installation in standard control panels or equipment enclosures. As part of Rockwell Automation's ControlLogix ecosystem, this chassis supports a modular approach to automation, allowing digital I/O, analog I/O, and communications modules to share a common backplane and communicate with the ControlLogix CPU across the four slots.