Series: PROTECT SRB family, Device version SRB 324ST/R‑24 V, revision 3
Safety Contacts:
- 3 safety contacts for “STOP 0” circuit
- 2 safety contacts for “STOP 1” circuit (adjustable delay 1–30 s)
Signal Outputs: 4 auxiliary signaling outputs for diagnostics/status
Safety Ratings:
- SIL 3 & PL e (STOP 0), SIL 2 & PL d (STOP 1), Cat. 4 (enabling path)
- Diagnostic coverage ≥ 99% / > 60%; PFHd ≈ 2×10⁻⁸/h
Reset Modes:
- Automatic reset or manual reset with edge detection; includes short-circuit detection
Power Supply: 24 V AC/DC (−15 %/+10 %)
Mechanical Data:
- DIN-rail mounting (EN 60715), width 45 mm, depth 121 mm, height 100 mm; weight ≈480 g
Environment & Safety Approvals:
- Ambient temperature −25 °C to +60 °C; IP40 enclosure (terminals IP20); EN IEC 62061, IEC 61508, ISO 13849-1 compliant
Protection Features:
- Electronic fuse, wire‑break & cross‑circuit detection, earth-fault detection, system diagnostics present

Schmersal – SRB 324ST/R-24 V (V.3) – PROTECT Series 24 V AC/DC Safety-Monitoring