Dynamic Control Period Adjustment for PLC Resource Optimization
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Solution Overview
Problem
Existing control systems in factory automation, such as those using PLCs, face inefficiencies due to a limited resource allocation, particularly in managing the execution intervals of input and output refresh processing, which are not optimized for variations in execution time, leading to suboptimal resource utilization.
Innovation Solution
A control system that includes a determination unit to assess whether the frequency components of sample values collected during different control periods are identical, allowing for the adjustment of the control period to optimize resource allocation by lengthening it when redundancy is determined, thereby allocating more time to peripheral service processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the control period is shortened to increase processing frequency, then productivity is improved, but resource utilization becomes inefficient due to repeated processing of identical data patterns
Solution Approach 1:
The system performs I/O refresh processing at periodic intervals defined by the control period. By dynamically adjusting this period based on frequency component analysis, the system optimizes the balance between processing frequency and resource efficiency, executing processing only when necessary rather than at fixed high frequency
Solution Approach 2:
The control period parameter is dynamically changed based on the analysis results of frequency components. When high-frequency components are detected indicating data changes, the control period is shortened to increase processing frequency. When low-frequency components dominate, the control period is lengthened to improve resource efficiency
2Loss of energy
If the control period is lengthened to improve resource efficiency, then resource utilization is optimized, but productivity decreases due to reduced processing frequency
Solution Approach 1:
The system continuously monitors I/O data and performs frequency component analysis to provide feedback on the actual data change characteristics. This feedback is used to dynamically adjust the control period, ensuring that resource efficiency is optimized without compromising productivity when data changes require faster processing
Solution Approach 2:
The control period is made dynamic rather than fixed. It automatically adjusts its length based on real-time analysis of frequency components in I/O data, allowing the system to adapt between short periods (high productivity) and long periods (high resource efficiency) according to actual operational needs
3Loss of energy
If the control period is dynamically adjusted, then resource utilization is optimized, but device complexity increases due to additional analysis and determination units
Solution Approach 1:
The control device integrates multiple functions into unified processing units. The determination unit performs frequency component analysis using standard signal processing techniques that can be implemented within existing PLC instruction sets, avoiding the need for separate dedicated hardware and minimizing the increase in device complexity
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 enables more efficient use of resources by dynamically adjusting the control period based on the analysis of frequency components, allowing for increased execution time for peripheral services without compromising data integrity, thus enhancing the overall performance of intelligent control devices.
Implementation Method 1
a conversion unit configured to generate a frequency component by performing a fast Fourier transform on the sample value group
Data Source
AI summary
A control system includes a control device that repeatedly performs a series of pieces of processing including I/O refresh processing and program execution processing. The control system includes: a first obtainment unit that obtains a first sample value group collected by repeatedly performing the I/O refresh processing in a first control period; a second obtainment unit that obtains a second sample value group collected by repeatedly performing the I/O refresh processing in a second control period longer than the first control period; a determination unit that determines whether a first frequency component in the first sample value group and a second frequency component in the second sample value group are substantially identical to each other; and a change unit that changes the first control period to the second control period under a condition that the first frequency component and the second frequency component are substantially identical to each other.