Safety Relay for Machine Guarding and Emergency Stop Circuits
The Omron G9SA321T30ACDC24 is a G9SA series safety relay with a 3NO+1NC contact configuration, designed for monitoring safety circuits such as emergency stop buttons, light curtains, and interlock switches. Supply is 24 VAC or 24 VDC, so it drops into existing 24 V control systems without a separate supply rail.
Contact Configuration and Wiring Constraints
Three normally-open safety contacts (3NO) handle the power path to the contactors or motor starters. The single normally-closed auxiliary (1NC) is typically used for feedback from the external contactors or as a status signal to the PLC. All contacts are screw terminals, so termination is straightforward for panel builders using ferruled or solid wire. The DIN rail mount option clips onto standard 35 mm rail; the screw mount option gives a direct panel fix if the rail is full.
Durability and Service Life
Electrical service life at 5 A is 100,000 cycles — enough for typical machine-guarding duty where the relay cycles only on fault or mode change, not every machine cycle.