Photoelectric Sensor High-Speed Sampling Circuit Design
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Solution Overview
Problem
Conventional photoelectric sensors that measure light transmission time for workpiece detection face challenges in sampling reflected light at high speeds, leading to increased device size and heat generation, which complicates accurate distance measurement and reliability.
Innovation Solution
A photoelectric sensor design that includes a light emitting element, a light receiving element, binarization processing, a capturing control circuit, and delay circuits to sample and integrate waveform data, allowing for high-speed sampling while reducing circuit scale and noise, enabling accurate distance measurement and reliable workpiece detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-speed sampling is performed to measure light transmission time accurately, then measurement precision is improved, but device complexity and size increase
Solution Approach 1:
The patent segments the light receiving signal into multiple discrete time slots corresponding to different distance ranges. By dividing the detection time into distinct intervals and assigning each to a dedicated storage element, the system achieves high-speed sampling without requiring complex continuous processing circuitry. This segmentation allows parallel processing of different distance measurements simultaneously.
Solution Approach 2:
The patent replaces complex mechanical or continuous electronic sampling systems with a discrete time-slot based detection mechanism. Instead of using high-speed analog-to-digital converters and complex signal processing electronics, the invention uses a time-divided multiplexing approach where reflected light in different time slots is directed to separate storage elements, significantly simplifying the overall circuit architecture.
2Measurement precision
If high-speed sampling is performed to capture reflected light accurately, then measurement precision is improved, but heat generation increases
Solution Approach 1:
The patent employs periodic emission of detection light pulses and corresponds each pulse to a specific time slot for receiving reflected light. This periodic action allows the system to sample reflected light at high speed by utilizing time-division multiplexing, where each period captures light from a specific distance range. The rhythmic, periodic operation reduces peak power consumption compared to continuous high-speed sampling.
3Productivity
If high-speed sampling is performed to measure light transmission time, then productivity is improved, but reliability decreases due to noise
Solution Approach 1:
The patent segments the detection process into multiple time slots, with each slot dedicated to capturing reflected light from a specific distance range. By concentrating detection resources on specific time slots rather than attempting to process all reflected light simultaneously, the system improves signal-to-noise ratio for each segment while maintaining high overall detection speed. This segmented approach allows for better noise filtering within each time slot.
Solution Approach 2:
The patent performs preliminary binarization processing on the light receiving signal before storing it in the waveform capturing section. By converting the analog light receiving signal into a binary signal in advance, the system reduces noise and simplifies subsequent processing. This preliminary action of binarization helps emphasize the reflected light components while suppressing noise before the data is stored and integrated.
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
The solution enables fast and accurate detection of workpieces by reducing circuit complexity, suppressing noise, and emphasizing reflected light components, resulting in a compact, reliable, and cost-effective photoelectric sensor.
Implementation Method 1
a light emitting element which repeatedly generates detection light; a light receiving element which receives reflected light of the detection light and generates a light receiving signal indicating a light receiving amount
Data Source
AI summary
Provided is a photoelectric sensor that detects a workpiece by measuring light transmission time. A photoelectric sensor includes: a light emitting element which repeatedly generates detection light; a light receiving element which receives reflected light of the detection light; a binarization processing section which binarizes a light receiving signal; a waveform detection section which detects waveform data indicating a temporal change of the binarized light receiving signal; a waveform integration section which matches light emitting timing of the light receiving element to integrate two or more pieces of waveform data and generates integrated waveform data; and a workpiece discrimination section which discriminates presence or absence of a workpiece based on the integrated waveform data, whereby the reflected light is sampled at a high speed while a circuit scale is suppressed, to detect the workpiece.