Schneider Electric AS-B821-108 PLC Module

Schneider Electric's Modicon AS-B821-108 is an 8-point discrete input module for the 800 Series modular I/O of Schneider Electric PLC systems. It accepts DC input signals from 10 to 60 V and uses True High sensing, converting external digital signals into a logic-level input for the connected controller. The module provides eight inputs, arranged as two points per common terminal, enabling compact wiring within standard Modicon 800 Series I/O racks. Designed to monitor positive-logic devices such as pushbuttons, limit switches, and proximity sensors, the AS-B821-108 serves as a scalable way to expand a control system’s input capability without changing the main controller. Integrated into Schneider Electric’s Modicon ecosystem, this 800 Series I/O module complements other discrete I/O options to support automation tasks across manufacturing lines, packaging systems, and material-handling equipment that rely on reliable, DC-driven digital inputs.