Industrial Safety Sensors and Machine Safety: Key Selection Points
Industrial Safety Sensors and Machine Safety: Key Selection Points
Machine safety is an important consideration in manufacturing plants and industrial facilities.
Automated machinery may contain moving parts, cutting tools, robotic equipment, conveyors, and other components that can create hazards during operation.
Safety-related sensing devices can form part of a properly designed machine safety system. However, selecting the correct device requires an understanding of the machine, the hazards, and the required safety functions.
This guide explains common safety sensing technologies and important factors to consider before selecting them.
What Are Industrial Safety Sensors?
Industrial safety sensors are devices designed for specified safety-related functions.
Depending on the product and application, they may detect a person entering a hazardous area, monitor the position of a protective guard, or support other machine safety functions.
Safety sensors must be distinguished from ordinary industrial sensors.
A standard proximity sensor or photoelectric sensor should not be assumed to provide a safety function unless the product is specifically designed and rated for that purpose.
Common Types of Safety-Related Devices
1. Safety Light Curtains
Safety light curtains use multiple light beams to detect entry into a protected area.
Depending on the design and application, they may be used around machinery where frequent operator access is required.
Selection depends on the required protective function, detection capability, installation arrangement, and relevant safety requirements.
2. Safety Interlock Devices
Safety interlocks are associated with protective guards, doors, or other access points.
Their function is to support a safety system that controls hazardous machine operation when a guard is opened or a required condition is not met.
The correct device depends on the guard design, machine risk assessment, and required safety performance.
3. Safety Laser Scanners
Safety laser scanners can monitor defined areas around machinery or mobile equipment.
Depending on the product and application, they may be used to detect people or objects entering configured protective fields.
Installation and configuration must follow the manufacturer’s instructions and applicable safety requirements.
4. Safety Controllers and Relays
Safety controllers and relays process signals from safety-related devices and support the required safety functions.
The selection must be based on the overall system architecture and required safety performance rather than the sensor alone.
Why Machine Risk Assessment Matters
Before selecting a safety device, the machine hazards and required protective measures should be assessed.
Relevant factors may include:
- Type of machinery
- Hazardous movement
- Operator access points
- Required stopping behaviour
- Machine stopping time
- Detection requirements
- Environmental conditions
- Required safety performance
- Applicable standards and regulations
The suitability of a safety sensor cannot be determined only by its physical dimensions or sensing range.
Five Factors to Consider When Selecting a Safety Sensor
1. Required Safety Function
Clearly define what the device must do.
For example, the application may require detection of access into a hazardous area or monitoring of a protective guard.
2. Detection Capability
For devices such as safety light curtains, confirm the required detection capability and protective field arrangement.
The choice depends on the hazard and the machine design.
3. Installation Position
The device must be installed at a suitable location based on the machine layout and relevant safety calculations.
Incorrect positioning can compromise the intended protective function.
4. Environmental Conditions
Consider dust, moisture, vibration, ambient light, temperature, and other conditions that may affect the device.
5. Compatibility With the Safety System
Check compatibility with the safety controller, relay, machine control system, and required interfaces.
Also review reset functions, monitoring requirements, and diagnostic capabilities where applicable.
Common Mistakes to Avoid
Avoid selecting a safety-related device solely because it resembles an existing product.
Other mistakes include:
- Using a standard sensor for a safety function without verifying its rating
- Ignoring the machine risk assessment
- Failing to check the required detection capability
- Installing the device without considering stopping time
- Ignoring compatibility with the safety controller
- Overlooking environmental requirements
- Assuming that one device alone makes the entire machine safe
Machine safety should be addressed at the system level.
Industrial Safety and Automation Product Enquiries
Voltec Engineering Limited supports industrial engineering and automation-related product requirements.
For safety-related product enquiries, provide the machine details, existing model number, required safety function, and relevant technical documentation.
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Conclusion
Industrial safety sensors are important components of appropriately designed machine safety systems.
Their selection requires consideration of the machine risk assessment, required safety function, detection capability, installation position, environmental conditions, and compatibility with the overall safety system.
For product information, contact Voltec Engineering Limited with your technical requirements.
