Mitsubishi ST1X4-DE1 4-Channel Digital Input Module

The Mitsubishi ST1X4-DE1 is a compact digital input module belonging to the MELSEC ST series of modular I/O systems. It provides 4 digital input channels for acquiring signals from field devices such as limit switches, pushbuttons, proximity sensors, and other 24V DC source-type sensors. The module supports online module replacement (OMC), allowing maintenance without system shutdown, and features LED indicators for input status and diagnostic information.

Compact and Flexible I/O Design

The ST1X4-DE1 features a slim 0.5-inch width profile, allowing high-density mounting in control cabinets where space is limited. The module is designed to plug onto a base module (ST1B series) that provides the physical connection for field wiring. This modular design separates the electronics from the wiring base, enabling quick module replacement without disturbing field cables. The source-type input configuration is compatible with positive-common sensors commonly used in industrial automation.

Online Module Replacement (OMC) for High Availability

The ST1X4-DE1 supports online module replacement, a feature that allows the module to be replaced while the system remains operational. When OMC is selected, the RUN LED flickers at 0.25-second intervals to indicate that the module is ready for removal. This capability is essential for critical processes where downtime must be minimized, such as continuous manufacturing lines and 24/7 facilities.

Application Domains

The ST1X4-DE1 is used in factory automation for acquiring signals from conveyor position sensors, packaging machinery for product detection, assembly line monitoring of limit switches, and building automation for door and access sensors. It is compatible with other MELSEC ST series modules, allowing mixed configurations of input and output modules on the same base system.