Siemens 3RA1921-1DA00 Industrial Safety Relay Module

Siemens 3RA1921-1DA00 is a link module that electrically and mechanically couples safety relays in the Siemens 3RV2.1/3RV2.2 and 3RT2.1 families, sold as an individual unit to enable tailored safety-circuit configurations. The module provides the essential interconnection and mounting alignment that lets you form compact safety chains within a control cabinet, simplifying wiring between relays and their monitored signals. It supports both AC and DC operation, making it compatible with a range of actuation schemes and power supplies used in industrial automation installations. Designed for direct integration with the specified relay platforms, the 3RA1921-1DA00 preserves the intended safety logic and cabling topology of linked relays, reducing assembly time and the risk of miswiring. Being available as a standalone linking component, it offers flexible deployment as you design or modify machine safety architectures, and its individual packaging supports straightforward replacement or reconfiguration without reworking broader relay assemblies. It also helps maintain traceability in safety systems by preserving a dedicated linking module per interconnection, supporting clear cabling and layout documentation.