Sensor System Mutual Interference Prevention via Delayed Synchronization
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Solution Overview
Problem
In sensor systems with multiple units, mutual interference occurs due to differing light projecting periods, leading to decreased response speed and measurement accuracy, especially when units of varying light projecting periods are mixed.
Innovation Solution
Each sensor unit has its light projecting period arbitrarily determined, with a delay time that differs from other units of the same type, allowing for independent operation and minimizing interference, even when units are adjacent, through the use of a connector unit that electrically connects light projecting and receiving elements to reduce signal transmission delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the synchronization signal is output when the slave unit projects the light, then the slave unit can be controlled to project light at a delayed time, but the light projecting period of the slave unit located at the lower stage is lengthened due to dependency on upper stage units
Solution Approach 1:
The master unit transmits the synchronization signal in advance before the slave units need to project light. This allows each slave unit to receive and process the signal without waiting for upper stage units to complete their projection, enabling independent timing control and preventing the propagation of extended periods from upper to lower stages.
2Productivity
If multiple sensor units operate simultaneously, then measurement coverage is improved, but mutual interference occurs due to overlapping light projection
Solution Approach 1:
Each sensor unit projects light periodically based on received synchronization signals, with each unit having a different period determined by its position in the system. This periodic operation with varying periods allows multiple units to operate simultaneously without their light projection overlapping in time, thus preventing mutual interference while maintaining comprehensive measurement coverage.
3Adaptability or versatility
If sensor units of different types with varying light projecting periods are mixed, then system versatility is improved, but the light projecting period of lower stage units is unnecessarily lengthened
Solution Approach 1:
Each slave unit is configured with local characteristics specific to its type and position, receiving synchronization signals from the master unit and determining its own light projecting period independently. This allows units of different types with different required periods to coexist in the same system without one unit's period constraints affecting others, enabling versatile system configuration while optimizing each unit's operating period for its specific function.
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 prevents mutual interference between identical sensor types, allows for flexible setting of operating periods, and maintains high determination accuracy by ensuring distinct light projection characteristics, even when operation times overlap.
Implementation Method 1
a light projecting element 207, 209 and a light receiving element 206, 208... a detection area 101 for detecting an object... the light receiving element receives the light
Implementation Method 2
a light receiving element 206, 208... the light receiving element receives the light
Data Source
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AI summary
In a sensor system including a plurality of photoelectric sensor units, a light projecting period suitably determined for each type is provided and mutual interference is prevented between sensor units of the same type. The sensor system includes the plurality of sensor units that are coupled in such a manner that signal transmission among the sensor units is possible. Each of the sensor units retains type information indicating a sensor type of the respective sensor unit, and sets a unique identification number of the respective sensor unit by signal transmission among the sensor units. Each of the sensor units operates after a delay time determined according to the identification number of the respective sensor unit elapses with a synchronization signal as a starting point. The synchronization signal is transmitted with a predetermined period from one of the plurality of sensor units that has a specific identification number. The delay time of each of the sensor units is determined such that an operating period of the respective sensor unit matches with a predetermined period, which is determined individually for each sensor type, and such that the delay time differs from the delay time of any other sensor unit having the same sensor type.