ABB 1SVR730840R0400 Safety Relay

ABB 1SVR730840R0400 CM-SRS.21S Current Monitoring Relay is a two-channel device that monitors the current flow in a single conductor and signals the condition through two changeover contacts. It is powered from a 24-240 V AC or DC supply and monitors the conductor between terminals B and C with a current range of 3 mA to 1 A RMS, enabling reliable detection of under- or over-current conditions. The unit provides two changeover outputs (2C/O), suitable for interfacing with PLCs, safety controllers, and other control circuits to generate interlocks, alarms, or stop signals when the monitored current deviates from set thresholds. Typical applications include motor protection, feeder monitoring, and safety-related control loops in industrial environments, where precise current monitoring helps prevent faults and supports safe shutdown or interlock strategies.