Light Curtain Receiver Grouping and Timing Offset
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Solution Overview
Problem
Existing light curtain systems experience increased response times due to transient processes caused by switching between receivers connected to amplifiers in multiplex mode, leading to corrupted signals and undesirable delays in object detection.
Innovation Solution
The light curtain divides receivers into groups, activating them with a time offset adapted to the activation interval, ensuring that switching disturbances are masked, and only the signal after the settling time is used for evaluation, thereby reducing response time and eliminating interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If receivers are activated individually via multiplexer switching, then the number of amplifiers is reduced, but switching transients corrupt the received signals and increase response time
Solution Approach 1:
The patent divides the array of receivers into multiple groups (first group, second group, etc.). Receivers within each group are activated individually via multiplexer switching, but different groups are activated with a time offset. This segmentation allows the system to use fewer amplifiers (one per group rather than one per receiver) while managing switching transients through temporal separation of group activations.
Solution Approach 2:
The patent introduces a waiting period (settling time) after each switching process before evaluating the received signals. This preliminary action allows switching transients to subside before signal evaluation begins, preventing transient corruption of detection signals while maintaining the multiplexed amplifier configuration.
2Reliability
If a waiting period is introduced after switching processes, then signal corruption from transients is avoided, but the response time of the light curtain increases
Solution Approach 1:
The patent implements periodic activation of receiver groups with a specific time offset between groups. The activation pattern cycles through different groups in sequence, with each group activated for a defined duration followed by a settling period. This periodic structure allows the system to maintain reliable signal detection while managing the time penalty through efficient cycling through groups.
Solution Approach 2:
The waiting period (settling time) is introduced as a preliminary action immediately following each switching process and before signal evaluation. By positioning this delay strategically in the timing sequence, the system ensures signal quality without unnecessarily extending the overall response time, as the settling occurs during the natural transition between receiver activations.
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
This approach results in a shorter response time for object detection signals and eliminates switching errors, enhancing the reliability and efficiency of the light curtain system.
Implementation Method 1
an array of transmitters emitting light beams, an array of receivers receiving light beams
Implementation Method 2
an array of receivers receiving light beams
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 (61-68), and an evaluation unit (8) in which an object detection signal is generated depending on the received signals from the receivers (61-68). The receivers (61-68) are divided into groups. Control means are provided by which the receivers (61-68) of each group are individually activated sequentially in multiplex operation during activation time intervals. The activation of the receivers (61-68) of different groups occurs with a time offset adapted to an activation time interval.