Photoelectric Sensor Edge Detection Synchronization

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Solution Overview

Problem

Existing photoelectric sensors face challenges in synchronizing the evaluation of pulsed light beams, particularly in maintaining accurate measurement times due to disturbances like extraneous light or coverage, which affects the determination of measurement intervals.

Innovation Solution

A method and photoelectric sensor design that synchronizes the acquisition of measured values by determining event times of positive and negative edges in the received signal, using an edge detector and control unit to derive clock information and measurement times without requiring additional oscillators or clock lines, ensuring synchronization with the received signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate oscillators and clock lines are used for synchronization, then measurement timing can be synchronized with light pulses, but device complexity increases

Engineering Contradiction:
Improvemeasurement timing synchronizationVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The receiving unit itself generates the clock signal needed for synchronization by detecting edges in the received signal. This self-service approach eliminates the need for separate oscillators and clock lines from the transmitting unit, reducing device complexity while maintaining precise measurement timing synchronization.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The receiving unit performs multiple functions: it detects the light signal, generates clock signals from the received signal edges, and uses these clock signals for synchronized measurement. This multi-functionality consolidates what would otherwise require separate dedicated components, reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If additional oscillators and clock lines are added for synchronization, then measurement times can be synchronized, but manufacturing cost increases

Engineering Contradiction:
Improvemeasurement times synchronizationVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The receiving unit generates its own clock signal from the received signal, eliminating the need for separate oscillator components and clock line infrastructure. This reduces component count and manufacturing complexity, directly lowering production costs while achieving the required synchronization precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The clock signal generation function is merged into the receiving unit's existing signal processing capabilities. By combining what would be separate functions (light detection and clock generation) into a single integrated unit, the patent reduces component count and manufacturing cost.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If synchronization is performed with pulsed light beams, then measurement points can be defined within pulses, but synchronization is interrupted by disturbances such as ambient light or cover

Engineering Contradiction:
Improvemeasurement points definitionVSAvoidsynchronization reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The receiving unit continuously monitors the received signal for edge transitions and uses these detected edges to generate and adjust clock signals in real-time. This feedback mechanism allows the system to adapt to signal conditions and maintain synchronization reliability even when disturbances occur, as the clock generation is continuously adjusted based on actual received signal characteristics.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary edge detection and clock signal generation based on initial received signals before actual measurements are taken. This preliminary synchronization establishes a baseline timing reference that can be used to define measurement points within pulses, preparing the system in advance for accurate measurement while maintaining the ability to adapt to disturbances.

Inventive Principle:
Principle #10Preliminary action

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 allows for quick and reliable synchronization of measurement times, reducing interference and enabling precise recording of measured values, even in asynchronous states, without the need for additional clock lines or separate oscillators.

Implementation Method 1

a receiving unit (3) arranged at a distance from the transmitting unit (2) for receiving the light beam (4) and converting it into a received signal (A)

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP3147694B1Method for operating a photoelectric sensor and photoelectric sensor
Publication Date: 2021.08.18 KARL MAYER STOLL R&D GMBH
  • EP3147694B1 patent drawingFigure 1
  • EP3147694B1 patent drawingFigure 2
  • EP3147694B1 patent drawingFigure 3a

AI summary

Method for operating a photoelectric sensor and photoelectric sensor. In a method for operating a photoelectric sensor, a pulsed light beam is emitted by a transmitter (2), which is received by a receiver (3) arranged at a distance from the transmitter (2) and converted into a received signal (A). In this method, measured values ​​(A1, A2) of the received signal (A) are acquired by an evaluation device. The acquisition of the measured values ​​is synchronized with the received signal (A) by the evaluation device. Event points (E) of positive and/or negative edges of pulses of the received signal (A) are determined by an edge detector (12) of the evaluation device.A control unit (13) of the evaluation device, to which the event times (E) are directed, determines a subsequent event time (E) after an event time (E) has been determined, provided it lies within a time interval around an expected subsequent event time (E). Synchronization is performed when at least two consecutive event times (E) have been determined. Measurement times (Z1, Z2) are then determined to acquire the measured values ​​(A1, A2) from the event times (E).