Multi-Optical Axis Sensor Teaching for Floating Blanking Stability

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Solution Overview

Problem

Multi-optical axis photoelectric sensors with floating blanking face challenges in optimizing the number of optical axes to be nullified due to irregular object movements, leading to unexpected machine stoppages and productivity degradation, as existing techniques lack effective methods for correct and prompt setting of maximum and minimum optical axis numbers.

Innovation Solution

A multi-optical axis photoelectric sensor system that includes a detection processing unit and a teaching processing unit, which determines the number of optical axes interrupted by an object and sets the maximum and minimum optical axis numbers through teaching, optimizing these values based on actual application conditions to prevent malfunctioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If floating blanking is used to nullify optical axes interrupted by movable objects, then the sensor can adapt to object movement, but the number of optical axes to be nullified cannot be correctly determined leading to unexpected machine stoppages

Engineering Contradiction:
Improveadaptability to object movementVSAvoidreliability of safety function
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The teaching processing unit performs preliminary scanning and teaching operations to determine the appropriate number of optical axes to be nullified before normal operation begins. This preliminary action establishes the maximum and minimum optical axis numbers that will be used during actual safety monitoring, preventing unreliable stoppages while maintaining adaptability to object movement.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from multiple scanning operations to dynamically determine the number of interrupted optical axes. By comparing results across multiple scans and using teaching operations, the system feedback-adjusts the maximum and minimum optical axis numbers to accurately reflect the actual object being monitored, ensuring both adaptability and reliability.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If the number of optical axes to be nullified is set based on calculations or trial and error, then the setting can be optimized, but the setting process takes much time and increases manhours

Engineering Contradiction:
Improveprecision of optical axis number settingVSAvoidtime for setting optimization
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The teaching processing unit enables the system to self-determine the appropriate number of optical axes to be nullified through automatic scanning and teaching operations. Instead of requiring manual calculation or trial-and-error adjustment by operators, the system automatically performs multiple scans, analyzes the results, and sets the maximum and minimum optical axis numbers, dramatically reducing setup time and manhours while maintaining precision.

Inventive Principle:
Principle #25Self-service

3Reliability

If blanking monitoring is implemented to detect object presence, then safety can be monitored, but the system may stop the machine when an optical axis switches state due to irregular object movement

Engineering Contradiction:
Improvereliability of safety monitoringVSAvoidproductivity due to unexpected stoppages
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The teaching processing unit performs preliminary scanning to establish the baseline number of interrupted optical axes before normal operation. This preliminary action creates a reference state that accounts for the normal position and movement pattern of the object, allowing the blanking monitoring function to distinguish between normal state changes and actual safety violations, preventing unnecessary stoppages while maintaining safety monitoring.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses partial blanking by nullifying only the specific number of optical axes that are actually interrupted by the object, rather than blanking all axes or using a fixed predetermined number. By dynamically determining the maximum and minimum optical axis numbers based on actual scanning results, the system applies blanking monitoring only where necessary, avoiding false stoppages while maintaining safety oversight.

Inventive Principle:
Principle #16Partial or excessive 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

The system correctly and promptly sets the maximum and minimum optical axis numbers for floating blanking and blanking monitoring, ensuring both productivity and safety by accurately determining the number of optical axes to be nullified, thereby preventing unexpected machine stoppages.

Implementation Method 1

an emitter unit, which includes a plurality of emitter elements aligned linearly, and a receiver unit, which includes a plurality of receiver elements aligned linearly in one-to-one correspondence to the emitter elements

Methodology Applied
Scientific EffectLight: Light

Implementation Method 2

The receiver unit determines the amount of light received by each of the receiver elements in synchronization with the lighting operation of the emitter elements

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentEP2975434B2Multi-optical axis photoelectric sensor system
Publication Date: 2025.01.15 OMRON CORP
  • EP2975434B2 patent drawingFigure 1
  • EP2975434B2 patent drawingFigure 2
  • EP2975434B2 patent drawingFigure 3

AI summary

Floating blanking is set correctly and promptly for an actual application. A detection processing unit determines, in a detection area (LC) including optical axes formed between emitter elements (11) and receiver elements (21), whether each optical axis is in an interrupted state after optical axis selection corresponding to one scan, and outputs a detection signal based on the determination result. When at least one of the optical axes is constantly interrupted by an object (OB) movable within the detection area (LC), the detection processing unit outputs the detection signal upon determining that the number of optical axes in an interrupted state is greater than a preset maximum optical axis number, and also outputs the detection signal upon determining that the number of optical axes in an interrupted state is smaller than a preset minimum optical axis number. The teaching processing unit obtains the number of optical axes interrupted by the object (OB) after optical axis selection corresponding to one scan, and sets the maximum optical axis number and the minimum optical axis number based on a result of comparison between the numbers of interrupted optical axes obtained in the respective scans.