Zander Aachen SR3A AC/DC 24V Safety switching device

Safe Coupling Relays – Standards-Compliant Signal Transmission for Safety Applications

In the process industry, it is essential to securely transmit safety-related signals from the control system to the peripheral devices. Conventional coupling relays reach their limits in this regard, as they can interrupt the safety chain and prevent the system from shutting down safely in case of danger.

The solution lies in safe coupling relays, which enable standards-compliant and tamper-proof signal transmission through their redundant design and self-monitoring. They guarantee safe coupling of safety-related signals up to SIL 3 / PL e.

---

### Functionality and Benefits of Safe Coupling Relays
Safe coupling relays are designed to maintain the safety function even in the event of internal failures or faults. This is achieved through the redundant design and cyclical self-monitoring of the system.

Key benefits at a glance:

• Standards-compliant coupling of safety-related signals (SIL 3 / PL e)
• Redundant design to ensure the safety function even in the event of failures
• Self-monitoring for early detection of errors
• Reliable separation of signal levels (galvanic isolation)
• Easy integration into existing control systems

---

### Typical Application Areas
Safe coupling relays are used in numerous industrial applications. Typical application areas include:

• Galvanically isolated signal coupling
Coupling digital 24V signals with 230V systems to safely control actuators or contactors.


• Secure transmission of sensor signals
Safe connection of sensor signals (e.g., from pressure monitors) to controllers to monitor safety-critical processes.


• Contact reinforcement
Amplification of controller outputs with limited output power to safely switch higher-power actuators or loads.


• Filtering of test pulses
Filtering of test pulses sent by safety controllers to ensure correct signal recognition.

---

### Technical Features of Safe Coupling Relays

• Maximum safety category: up to PL e / SIL 3
• Redundant relay outputs to meet safety requirements
• Galvanic isolation of input and output signals
• Self-monitoring function for early detection of failures or errors
• Connection options: Compatible with various types of sensors and controllers
• Easy integration into existing control systems with DIN rail mounting

---

### Conclusion
Safe coupling relays ensure that safety-related signals are reliably transmitted from a safety controller to the peripherals. They prevent the interruption of the safety chain and enable the operation of machines and systems up to the safety level SIL 3 / PL e.

With their redundant design, galvanic isolation, and self-monitoring, safe coupling relays provide maximum safety for people and machines. Whether for signal amplification, galvanic isolation, or secure connection of sensors and controllers – safe coupling relays are the ideal solution for industrial applicat