Time-of-Flight Safety Light Barrier With Single-Sided Transceiver
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Solution Overview
Problem
Conventional safety photoelectric barriers are costly to manufacture and time-consuming to install, and they fail to meet the safety integrity level 3 requirements as defined by international standards, particularly in industrial applications.
Innovation Solution
A single-sided transceiver bar with a housing, multiple transceiver modules, and a controller module, utilizing a time-of-flight system with radiation emitting and detecting units, and redundant photosensitive elements to evaluate distance and intensity information, generating a binary output signal for object detection within a protective field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional active-active photoelectric barrier with separate emitter and receiver bars is used, then the safety monitoring function is provided, but the fabrication cost is high and installation is time-consuming
Solution Approach 1:
The patent combines the emitter and receiver into a single transceiver bar with integrated transceiver modules. Each module contains both a radiation emitting unit (LED) and a radiation detecting unit (photosensitive elements) that work together to monitor the protective field, eliminating the need for separate emitter and receiver bars while maintaining safety functionality
Solution Approach 2:
The transceiver bar serves multiple functions: it emits radiation beams, detects reflected radiation, measures distance to the reference target, monitors the protective field for intrusions, and provides safety outputs. This multi-functional design replaces the conventional two-bar system while reducing complexity and installation time
2Device complexity
If a single-sided transceiver bar with time-of-flight system is used, then the fabrication cost is reduced and installation is simplified, but the safety integrity level must be ensured
Solution Approach 1:
The system uses time-of-flight measurement to continuously monitor the distance between the transceiver bar and the reference target. The signal processing unit calculates distance based on the time delay of reflected radiation, providing real-time feedback to detect any intrusions into the protective field and generate appropriate safety signals
Solution Approach 2:
The patent replaces the conventional mechanical alignment and dual-bar physical structure with an optical time-of-flight measurement system. The distance measurement and intrusion detection are achieved through optical radiation measurement and electronic signal processing rather than mechanical structures, enabling a single-sided design that meets safety integrity requirements
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 solution reduces manufacturing costs, simplifies installation, and achieves a high safety integrity level by evaluating distance and intensity information redundantly, meeting the requirements for SIL 3 safety standards while providing a cost-effective and efficient solution for industrial applications.
Implementation Method 1
a signal processing unit for evaluating the detected radiation regarding a distance information and an intensity information
Implementation Method 2
a radiation detecting unit for detecting radiation incident on the transceiver module
Data Source
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AI summary
The present invention relates to a safety photoelectric barrier for monitoring a protective field and to a corresponding method. A safety photoelectric barrier (100) comprises a single-sided transceiver bar with a housing (102), a plurality of transceiver modules (104) each having a radiation emitting unit (112) for emitting radiation towards a reference target (108), a radiation detecting unit (114) for detecting radiation incident on the transceiver module (104), and a signal processing unit for evaluating the detected radiation regarding a distance information and an intensity information and for generating a binary output signal indicating the presence or absence of an object within the protective field. A controller module (126) evaluates the binary output signals and generates a safety signal in response to the evaluated output signals. The radiation detecting unit comprises at least a first and a second photosensitive element (114) for redundantly evaluating the distance and intensity information.