How to Choose Safety Relays for Industrial Automation?
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- Issue Time
- Sep 12,2024
Summary
Choosing safety relays for industrial automation involves defining app requirements, considering load type, action characteristics, safety levels, environmental factors, electrical performance, safety features, and brand/service. Ensuring compatibility, reliability, and safety standards is crucial for stable system operation.
In industrial automation and control systems, safety relays, as key components, not only perform the function of safely switching circuits, but also are directly related to the safe and stable operation of the entire production line. Choosing the right safety relay is an important part of ensuring the safety of the production environment and increasing the reliability of the equipment.
Before Selecting a Safety Relay, You Must First Define the Specific Application Requirements
This includes, but is not limited to
Load type and specifications: Understand whether the load to be controlled is DC or AC, as well as the load current, voltage, and other parameters to ensure the selected relay's rating will match.
Action Characteristics: Specify the key parameters such as trip current, release current, operating time and release time of the relay to meet the precise requirements of the control system.
Safety Level: Determine the required safety level according to international standards (e.g. EN ISO 13849, IEC 62061, etc.) to ensure that the selected relay meets the safety standards.
Consider the Environmental Factors of Safety Relay Application
The industrial environment is complex and changing, the selection of safety relays must also consider the following environmental factors:
Ambient operating temperature: The load capacity of the relay is closely related to the ambient operating temperature. As the ambient temperature increases, the load capacity of the relay decreases. Therefore, a sufficient margin should be included in the selection.
Seismic and Dust Resistance: According to the vibration intensity and dust concentration of the site environment, select safety relays with appropriate seismic and dust ratings.
Physical layout: Consider the installation space and heat dissipation requirements of the relay, and select products with appropriate size, easy installation and good heat dissipation performance.
Safety Relay Evaluating Electrical Performance
Electrical performance is one of the most important considerations when selecting safety relays:
Input and output parameters: Ensure that the safety relay's input voltage and current match the control system, and that the output voltage and current match the load requirements.
Overload protection: Consider whether the relay has overload protection to handle sudden overload conditions and protect circuit and equipment safety.
DVDT capability: For high-speed switching application scenarios, consider the DVDT (rate of change of voltage) capability of the relay to ensure it can operate stably.
Focus on Safety Features of Safety Relay
The safety relay should have the following safety features:
Forcibly guided contacts: The use of forcibly guided contacts ensures that the safety state of the circuit can still be maintained in the event of a fault such as contact sticking.
Monitoring function: Some high-end safety relays have self-test and monitoring functions, which can monitor the safety relay's operation status in real time and send alarm signals in case of failure.
Redundant design: Some safety relays adopt redundant design to improve the reliability and safety of the system.
Safety Relay QSRN
Power supply: 24 V DC
Relay safety output: 3NO + 1NC (PNP or NPN)
Maximum switching capacity: 12 A (Distributed on all safety output contacts)
Transistor signal output: <500 mA 24 V DC
Contact resistance: <100 mΩ
Size: 117 × 100 × 22.5 mm
Shell material: flame retardant PA66
Storage temperature: -40℃ ~ 105℃
Consider Brand and Service of Safety Relay
Brand selection: choose safety relays from well-known brands, which usually have higher product quality, better after-sales service and a wider product range.
Technical support and service: understand the supplier's technical support capabilities and after-sales service policies so that problems encountered during use can be resolved in a timely manner.
In conclusion, the selection of suitable safety relays must consider the application requirements, environmental factors, electrical performance, safety features, as well as brand and service and other aspects. Through scientific and reasonable selection, it can ensure the safe and stable operation of industrial automation and control systems, and create more value for the enterprise. As practitioners in the field of industrial electrical safety, we should continue to improve our professionalism, keep pace with industry trends, and contribute to industrial safety.
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