Light Curtain Access Control for Authorized Mobile System Entry
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Solution Overview
Problem
Existing methods for operating technical installations with mobile systems in danger zones result in unnecessary machine standstills due to unauthorized access, leading to production losses and safety hazards, and require complex data exchanges with higher-level control systems.
Innovation Solution
A method involving a light curtain that generates a protective field in the access zone, allowing mobile systems to temporarily deactivate it using light communication, enabling authorized access without needing higher-level control system interaction, and ensuring safety by detecting unauthorized entries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective field is activated in the access zone to prevent unauthorized access, then safety is improved, but authorized mobile systems are blocked from entering the access zone
Solution Approach 1:
The protective field's activation state is made dynamic rather than static. The light curtain can switch between active and inactive states based on real-time communication with mobile systems. Authorized mobile systems that transmit identification signals can temporarily deactivate the protective field to pass through, while the field remains active to prevent unauthorized access. This dynamic behavior resolves the contradiction by adapting the safety mechanism to the specific needs of each situation.
Solution Approach 2:
The system changes the activation parameter of the protective field based on the presence and authorization status of mobile systems. When an authorized mobile system approaches and communicates its identification, the protective field parameter switches from 'active' to 'inactive' state, allowing passage. Once the mobile system passes, the field returns to the 'active' state. This parameter change enables both safety and authorized access.
2Reliability
If a light curtain with protective field is used to monitor the access zone, then safety monitoring is improved, but data traffic via higher-level communication systems increases
Solution Approach 1:
The identification and authorization verification function is extracted from the higher-level communication system and implemented directly at the light curtain level. The light curtain's stationary communication unit can independently receive and verify identification signals from mobile systems using simple optical communication (light signals). This extraction eliminates the need for complex data exchanges with higher-level systems, reducing data traffic while maintaining safety monitoring capabilities.
Solution Approach 2:
The light curtain system performs self-verification of mobile system authorization by receiving identification signals directly and determining whether to deactivate the protective field. This self-service capability eliminates the need for continuous communication with higher-level control systems, reducing data traffic and enabling the light curtain to autonomously manage access based on received identification signals.
3Productivity
If the protective field is completely deactivated to allow mobile system passage, then mobile system access is improved, but safety monitoring capability is reduced
Solution Approach 1:
The protective field transitions dynamically between active and inactive states based on the presence and authorization of mobile systems. When an authorized mobile system is detected and communicates its identification, the field deactivates to allow passage. Once the mobile system passes through the access zone, the field automaticallyreactivates to resume safety monitoring. This dynamic switching ensures that the field is completely inactive only when necessary for authorized passage, while maintaining safety monitoring capability at all other times.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces data traffic and ensures safe, reliable operation by allowing authorized mobile systems to traverse access zones without machine standstills, while preventing unauthorized access and reducing safety risks.
Implementation Method 1
a light curtain for monitoring the access zone
Implementation Method 2
a mobile communication unit of the at least one mobile system transmits a request signal to a stationary communication unit of the light curtain
Data Source
AI summary
In a method for operating a technical installation that includes an outer zone, a danger zone, an access zone which provides for access from the outer zone to the danger zone, a light curtain for monitoring the access zone, and at least one mobile system: a protective field is generated and activated in the access zone by the light curtain before entry of the at least one mobile system into the access zone; when the at least one mobile system approaches the access zone, a mobile communication unit of the at least one mobile system transmits a request signal to a stationary communication unit of the light curtain; and after reception of the request signal by the stationary communication unit the protective field is deactivated by the light curtain. A technical apparatus is configured to carry out the method.