The Siemens 3SK1121-1CB42 is a SIRIUS 3SK1 Advanced safety relay basic unit designed for machine safety applications with adjustable time delay functionality. It is used in systems where a controlled shutdown (OFF-delay / delay safety function) is required after an emergency stop or safety signal.
This relay is commonly used in industrial automation, machine guarding, conveyor systems, and safety interlocking circuits.
• Siemens SIRIUS 3SK1 Advanced series safety relay
• Part Number: 3SK1121-1CB42
• Supply voltage: 24V DC
• Adjustable time delay: 0.5 to 30 seconds
• 2 safety outputs (instantaneous NO contacts)
• 2 safety outputs (delayed NO contacts)
• Dual-channel safety input monitoring
• Cross-circuit detection for higher safety integrity
• DIN rail mounting (22.5 mm compact design)
• Screw terminal connection
• LED status & diagnostic indication
• Supports emergency stop and safety gate monitoring
• Suitable for Category 4 / PL e safety systems (system dependent)
| Parameter | Specification |
|---|---|
| Product Series | Siemens SIRIUS 3SK1 |
| Part Number | 3SK1121-1CB42 |
| Product Type | Safety Relay (Advanced with Time Delay) |
| Supply Voltage | 24V DC |
| Time Delay Range | 0.5 – 30 seconds |
| Safety Outputs | 2 NO instantaneous + 2 NO delayed |
| Input Type | Dual-channel safety inputs |
| Mounting Type | DIN rail |
| Width | 22.5 mm |
| Function | E-stop / safety gate / controlled stop (OFF delay) |
| Standards | ISO 13849-1, IEC 61508, IEC 60204-1 |
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