The Mitsubishi Electric RX42C4 digital input module is a MELSEC local‑unit I/O device designed to feed digital signals from sensors and switches into a Mitsubishi PLC. It is used in automated control systems to capture discrete input states for processing by the MELSEC controller. As part of the MELSEC family, the RX42C4 provides a compact digital input interface that installs alongside other MELSEC I/O modules to support basic automation tasks.
