Performance Level (PL): PL e, Safety Integrity Level (SIL): SIL 3, Category: Cat. 4, Operating voltage: 24 V DC, ± 20%, Number of channels: 4, Safety output: 2 relay outputs, positively guided normally open contacts, Signal output: Output to display the switching state of the OSSDs, Connection: Screw terminals, Cable cross-section 0.2 ... 2 mm2, Ambient temperature: 0 ... 50 °C (32 ... 122 °F)