Schneider Electric B559 Programmable Logic Controller Module

Schneider Electric B559 is a Modicon 984-series/500-series universal DC input module that provides four discrete input channels for field signals. Designed to mount in a Modicon I/O rack, the B559 accepts DC input signals from 9 to 56 V (DC) and groups its four inputs into two common terminals to streamline field wiring. Labeled as a universal DC input module (true low), it is intended for digital sensing applications such as pushbuttons, proximity sensors, limit switches, and other common 9–56 V devices. The module feeds clean logic states into the PLC backplane, enabling reliable digital input conditioning within industrial automation systems. When paired with Schneider Electric Modicon controllers from the 984-series or 500-series I/O backplanes, the B559 integrates with the broader Modicon I/O ecosystem for scalable automation. The four independent input circuits share a common source and return to the controller, reducing wiring complexity while preserving channel isolation. Typical installation scenarios include machine automation, packaging lines, and manufacturing cells where crisp, low-voltage DC input signals must be read by the PLC. With its four-channel footprint and compatibility with legacy Modicon hardware, the B559 serves as a compact, drop-in component for legacy automation setups requiring reliable DC Input capability in a 9–56 VDC range.