Light Curtain Amplifier Self-Testing for Reliable Object Detection
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Solution Overview
Problem
Existing light curtains suffer from malfunctions in amplifiers leading to incorrect object detections, which are not adequately addressed by existing technologies.
Innovation Solution
A light curtain design with a test device that periodically tests the amplifiers within predetermined time intervals, generating error messages or stopping the system if malfunctions are detected, and using an addressing unit to specify these intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If amplifiers are used to amplify received signals to increase detection sensitivity, then detection sensitivity is improved, but amplifier malfunctions can cause incorrect detections which reduces reliability
Solution Approach 1:
The patent implements periodic self-tests of amplifiers before they are used for actual detection. The test device generates test signals that are amplified by the amplifiers and compared against expected values, allowing the system to detect amplifier malfunctions before they cause incorrect object detections. This preliminary testing ensures that amplifiers are functioning correctly before contributing to detection decisions.
Solution Approach 2:
The patent establishes a feedback mechanism where the output of each amplifier is fed back to a test device that compares the actual output against expected values. This feedback loop continuously monitors amplifier performance and generates error messages when deviations are detected, allowing the system to identify and respond to amplifier malfunctions that would otherwise cause incorrect detections.
2Reliability
If periodic testing of amplifiers is implemented to detect malfunctions, then detection reliability is improved, but system complexity increases due to additional test devices and control mechanisms
Solution Approach 1:
The patent combines the test device functionality with the existing evaluation unit that processes detection signals. The same processing circuitry is used for both normal detection operations and amplifier testing, reducing the need for completely separate testing hardware. The test signals are integrated into the existing signal processing pathway, allowing amplifier monitoring without requiring entirely independent testing infrastructure.
Solution Approach 2:
The evaluation unit serves multiple functions: it processes detection signals from receivers during normal operation and simultaneously performs amplifier self-tests by generating test signals and comparing amplifier outputs against expected values. This multi-functionality reduces the need for dedicated testing hardware and simplifies the overall system architecture while maintaining reliable amplifier monitoring.
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
Ensures reliable object detection by preventing false alarms due to amplifier malfunctions through regular testing and fail-safe design.
Implementation Method 1
an arrangement of transmitters emitting light beams, an arrangement of receivers receiving light beams
Implementation Method 2
the received signals are amplified in amplifiers before they are fed to the evaluation unit
Data Source
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AI summary
The invention relates to a light curtain (1) for detecting objects in a monitoring area, comprising an arrangement of light beams (3) emitting transmitters (4), an arrangement of light beams (3) receiving receivers (6), and an arrangement of amplifiers (12) in which the received signals from the receivers (6) are amplified. In an evaluation unit (8), an object detection signal in the form of a binary switching signal is generated based on the amplified received signals. The switching states of this signal indicate whether an object is present in the monitoring area or not. At least one test device is provided by means of which the amplification characteristics of the amplifiers (12) are tested within predetermined time intervals.