3RH2921-1DA02 SIMATIC PLC

The Siemens 3RH2921-1DA02 is a lateral-mounting auxiliary switch block from the SIRIUS 3RH2 series, designed to expand the control circuit capacity of SIRIUS 3RT2 power contactors and 3RH2 contactor relays. It provides 2 Normally Closed (NC) contacts with screw terminals, enabling reliable status feedback, interlocking, and signaling functions in industrial control panels. This auxiliary switch is a current, active product (PLM status PM300) and is the modern counterpart to the discontinued 3RH19 series, ensuring long-term availability for new installations and maintenance alike.