The Omron G7SA-4A2B DC21 is a safety relay with a 24 VDC coil and force-guided contact configuration of 4 normally-open and 2 normally-closed poles. This contact arrangement is standard for dual-channel safety circuits where the NO contacts carry the load and the NC contacts provide feedback to the safety controller, ensuring the relay cannot weld closed without detection.
Mounts on a DIN rail in the control panel. The force-guided contacts meet the requirements of EN 50205 for safety applications — if one contact welds, the others cannot close, so the NC feedback loop will stay open and the safety controller will see the fault. This is the standard relay for Category 3 / PL d or SIL 2 circuits where you need to monitor the contactor or valve state.