The ABB CM‑SRS.12S is a single‑phase current monitoring relay designed to monitor AC and DC current in control and protection circuits. It is part of ABB’s CM series of current monitors, providing reliable over‑ and under‑current detection with adjustable measurement ranges. The relay uses RMS current measurement to ensure accurate sensing of varying loads. A single changeover (SPDT) output contact allows for signaling or control of external devices (e.g., alarms, contactors, or breakers) when monitored current goes above or below a set threshold. The device is compact and DIN‑rail mountable, with screw‑type connection terminals suitable for secure industrial installation. Its hysteresis is adjustable to optimize stability around the trip point.