Conveyor Safety Control via Sensor Pattern Learning
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Solution Overview
Problem
Conventional conveyor safety systems rely on dedicated sensors for single safety functions, which limits adaptability and does not ensure safety integrity when changes occur, and they do not effectively monitor the overall safety of complex conveyor systems.
Innovation Solution
A computer-based safety control method that learns sensor patterns and logic relationships during operation, allowing for continuous monitoring of safety integrity by comparing sensor outputs with pre-stored reference patterns and logic, enabling adaptive safety responses even without absolute sensor failure indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dedicated sensors are used for single safety functions, then safety monitoring is simple and reliable, but adaptability to changes and overall safety integrity of complex conveyors cannot be ensured
Solution Approach 1:
The patent applies universality by enabling a single sensor to serve multiple safety functions simultaneously. Instead of dedicating one sensor to one function, the system allows sensors to monitor multiple parameters and contribute to overall safety integrity assessment, thereby improving adaptability without proportionally increasing system complexity
Solution Approach 2:
The patent merges multiple sensor signals and safety function evaluations into a unified safety integrity assessment performed by the computer system. By combining sensor outputs and evaluating them against stored logic and reference patterns, the system achieves comprehensive safety monitoring without requiring separate dedicated sensors for each function
2Reliability
If conventional safety chains with series-connected switches are used, then safety response is immediate and simple, but the system cannot monitor overall safety integrity or adapt to changes in complex conveyor systems
Solution Approach 1:
The patent replaces the mechanical/electrical safety chain approach with a computer-based monitoring system. Instead of relying on series-connected switches that provide only binary safety responses, the system uses a computer to evaluate sensor patterns against stored logic and reference patterns, enabling comprehensive safety integrity assessment that adapts to complex conveyor configurations
Solution Approach 2:
The patent implements feedback by continuously monitoring sensor outputs, comparing them against reference patterns stored in the computer system, and evaluating safety integrity based on this comparison. The system learns during operation and uses this feedback to maintain high safety integrity while adapting to changes in the conveyor system
3Ease of operation
If absolute sensor failure indications are required for safety actions, then false safety stops are reduced, but safety responses cannot be triggered when overall system integrity is compromised
Solution Approach 1:
The patent applies partial action by triggering safety responses based on partial degradation of safety integrity rather than requiring complete sensor failure. The system evaluates the overall pattern of sensor outputs and can initiate safety actions when the collective signal pattern deviates from reference patterns, even if individual sensors are still functioning, thereby maintaining safety responsiveness while avoiding false stops
Data Source
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AI summary
A conveyor system has a plurality of sensors coupled to a computer system, the computer system being programmed to check a number of safety functions greater than the number of sensors. A method of controlling the safety function of the conveyor comprises providing signals from a plurality of sensors disposed in relation to the conveyor to a computer system; operating the conveyor in a learn mode; during operation in the learn mode determining in the computer system the relationship between the sensor output signals and pre-stored logic in the computer system which describes the physical geometry of the possible conveyor types and permissible operating characteristics thereof and determining the relationship between the sensor output signals to establish the safety integrity of the sensors, and storing sensor signal patterns as a reference pattern; and subsequently operating the conveyor in a run mode in which safety functions are monitored; and during the run mode comparing in the computer system the pattern of sensor signals with the reference pattern and with the pre-stored logic so as to establish the safety integrity of the sensors, of the computer system and of the operation of the conveyor.