When selecting a safety relay unit, the following factors should be considered:
1. Safety level requirements (Performance Level / SIL)
Based on the risk assessment results of the application scenario, select a safety relay that meets the corresponding safety level (such as PL e, SIL3).
2. Input signal type
Clarify the type of safety equipment connected (such as safety light curtains, safety door locks, emergency stop buttons, two-hand buttons, etc.) to ensure input compatibility.
3. Output type and quantity
Determine whether normally open, normally closed, delayed or instantaneous output is required based on the number of devices to be controlled and the control method.
4. Redundancy and diagnostic capabilities
Select relays with corresponding functions based on whether the application requires dual-channel redundancy, circuit self-test, short-circuit monitoring and other functions.
5. Power supply voltage
Confirm whether the power supply voltage of the control system (such as 24V DC or 230V AC) matches the safety relay.
6. Installation method and volume
Consider whether the size of the relay is suitable for the control cabinet space and whether it supports rail installation.
7. Expandability
If multiple safety loops are required, consider whether expansion modules or multi-input designs are supported.
8. Brand compatibility and certification standards
Choose products with CE, TÜV and other certifications, and ensure compatibility with existing control systems or PLCs.
These selection factors help ensure that safety relays meet safety standards in actual applications and have good system integration and stability.
