Allen-Bradley 1771-0A 120 Volt Industrial Input Module

The Allen-Bradley 1771-0A 120V Industrial Input Module is an industrial control I/O device designed to capture external 120-volt signals and deliver them to a compatible Allen-Bradley controller. Used in automation and process-control environments, it serves as the interface for reading field-device inputs on a control panel or machine, translating high-voltage signals into digital inputs the controller can process. The key specification is its 120V input rating, which defines the voltage level considered active by the module. This makes it suitable for applications where 120V signaling is standard, such as monitoring relays, contact closures, or other 120V sensor outputs connected to the controller’s input channels. As a part of Allen-Bradley’s legacy I/O lineup, the 1771-0A module is intended for use with compatible controllers that support this input architecture, providing a straightforward plug-in option to expand input capability in industrial automation systems.