The Omron G7Z-4A-11Z-R 24VDC is a safety relay with a 4PST-NA main contact rated for 40 A and a separate SPST-NA/SPST-NC auxiliary contact rated for 1 A. The 4PST-NA (4-pole, normally open) main contacts handle the load circuit in a safety chain — think emergency-stop or guard-door monitoring where you need positively-guided force-guided contacts to drop the load reliably. Coil is 24 VDC, which is the standard control voltage across most industrial panels.
What the 40 A main rating means in a safety circuit
The 40 A rating on the 4PST-NA contacts is the thermal current (Ith) for the main poles — it tells you the contacts can carry 40 A continuously without overheating. For motor or resistive loads, the actual switching capacity will be lower (typically AC-1 or AC-15 duty), but the 40 A frame means this relay is sized for larger contactors or power supplies inside the safety circuit, not just signal-level loads. The 1 A auxiliary contact is for feedback only; don't parallel it into the main load path.
This relay mounts on a DIN rail (standard 35 mm) inside a control cabinet. The 4PST-NA + 1 AUX configuration fits a compact footprint — Omron's G7Z series is designed for safety applications where space is tight and you need positively-guided contacts per EN 50205. Wire the main contacts in series with the load (contactor coil or power supply enable), and use the auxiliary contact for the safety PLC feedback loop.