The Omron G9SA-EX301 is a safety relay extension module that adds a second safety channel to a G9SA-series safety relay base unit. It accepts two input signals and switches one normally-open main contact plus one normally-closed auxiliary contact, both rated 5 A. The 17.5 mm wide DIN-rail housing keeps panel fill factor tight — it's the same width as a standard miniature circuit breaker, so it slots into a crowded enclosure without re-laying the backplane.
The 5 A contact rating covers most pilot-duty loads — contactor coils, solenoid valves, indicator lamps — but not direct motor switching. The SPST-NC auxiliary is a feedback contact that the base safety relay monitors; if the extension loses its seal, the base opens both channels. Response time is 10 msec, which is typical for electromechanical safety relays and fast enough for Category 3 / PL d circuits per EN 954-1. The adjustable timing function means you can set off-delay on the extension's output, useful for staggered stop sequences on a conveyor or press guard.
This module is the expansion slice — it cannot run standalone. It mates to a G9SA base unit (like the G9SA-301 or G9SA-321) via the internal bus, extending the number of monitored input channels and output contacts. The IP20 finger-safe housing means it's intended for a locked control panel, not a washdown zone. The LED indicator shows input status, which helps during commissioning when you're chasing a mis-wired e-stop string.