Safety Switch Signal Emulation for Periodic Self-Testing
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Solution Overview
Problem
Existing safety switches for monitoring the closed position of protective devices in automated systems lack comprehensive testing capabilities, particularly for safety-relevant components like transceivers and memory units, limiting their effectiveness in safety-critical applications.
Innovation Solution
A device with a sensor and actuator system that includes a signal emulator and a computing unit, allowing for a functional test by switching between normal and test modes, enabling the generation and emulation of receiving circuit signals to assess the detector element's functionality and simulate sensor interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a self-diagnosis function is implemented in existing safety switches, then basic functionality can be tested, but comprehensive testing of safety-relevant components (transceiver, memory unit) cannot be performed
Solution Approach 1:
The patent applies the copying principle by creating a virtual model (signal emulator) that replicates the sensor element's signal generation functionality. The signal emulator generates receiving circuit signals identical to those produced by the actual sensor element, enabling comprehensive testing of the detector element, transceiver, and memory unit without requiring physical sensor actuation. This virtual copy allows thorough testing of safety-relevant components while avoiding the limitations of physical testing arrangements.
Solution Approach 2:
The patent introduces a switching element as an intermediary component that selectively connects the detector element to either the sensor element or the signal emulator. This mediator enables the testing system to alternate between normal operation mode (sensor element connected) and testing mode (signal emulator connected), facilitating comprehensive component testing without disrupting the normal sensing functionality. The switching element resolves the contradiction by providing a controlled interface between testing and operational states.
2Reliability
If the sensor element is continuously connected to the detector element for monitoring, then the closed position can be monitored, but the receiving circuit cannot be thoroughly tested
Solution Approach 1:
The patent applies the dynamics principle by making the connection between the sensor element and detector element switchable rather than fixed. The switching element dynamically reconfigures the circuit connections based on operational requirements: during normal operation, the sensor element is connected for continuous monitoring; during testing, the signal emulator is connected for comprehensive receiving circuit testing. This dynamic switching capability resolves the contradiction by allowing the system to adapt its configuration for different functional states.
Solution Approach 2:
The patent implements periodic action through the switching element that alternates between connecting the sensor element and the signal emulator to the detector element. This periodic switching enables the system to cycle between normal monitoring operations and comprehensive testing operations, ensuring both continuous safety monitoring and thorough testing capability. The periodic alternation between operational and testing states allows the receiving circuit to be thoroughly tested without compromising ongoing safety monitoring functions.
3Reliability
If a signal emulator is introduced to enable comprehensive testing, then safety-relevant components can be tested, but the device structure becomes more complex
Solution Approach 1:
The patent applies the universality principle by designing the signal emulator to perform multiple functions: it generates receiving circuit signals for testing the detector element, simulates various sensor responses for comprehensive component testing, and can be selectively connected to replace the sensor element. The switching element also serves dual purposes by enabling both normal operation and testing modes. This multi-functionality reduces the need for separate dedicated testing equipment, thereby limiting the increase in device complexity while achieving comprehensive testing capability.
Data Source
Figure 1~2e
Figure 3~5
Figure 6~7
AI summary
The invention relates to a device, such as a door contact switch, comprising a sensor (4) and an actuator (3), wherein the sensor (4) has a receiver circuit (5) with a sensor element (6) and a detector element (8), as well as a processing unit (10) connected to the detector element (8). The sensor element (6) is configured to interact with the actuator (3) during normal operation when a switching distance (2) between the sensor (4) and the actuator (3) falls below a certain threshold to generate a first receiver circuit signal (7a). The detector element (8) is configured to generate a first output signal (9a) based on the first receiver circuit signal (7a) and to transmit it to the processing unit (10). Furthermore, the receiver circuit (5) includes a signal emulator (19) and a switching element (17), wherein the signal emulator (19) is configured to generate a second receiver circuit signal (7b) during test operation.The detector element (8) is configured to generate a second output signal (9b) depending on the second receiving circuit signal (7b) and to transmit it to the processing unit (10). The device (1) is configured and/or programmed to repeatedly switch, in particular periodically or aperiodically, from normal operation to test operation and back to normal operation by means of the switching element (17).