PLC Control System Time-Series Data Alignment
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Solution Overview
Problem
Existing control systems face difficulties in comparing actual input and output signals with internal variables, making it inefficient to adjust devices, particularly in larger systems, as the trace function within these systems does not accurately align sampling data with actual signal changes.
Innovation Solution
A control system comprising a PLC system, an input unit, an output unit, and a controller with a sampling unit that generates and displays time-series data aligning actual sampling data with variable sampling data and output instruction data on the same time axis, allowing for easy adjustment of devices without burdensome alignment procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the trace function is implemented internally in the controller to sample variables, then the controller can monitor internal variable changes, but the sampling data cannot be accurately compared with actual input and output signals due to independent sampling timing
Solution Approach 1:
The patent merges the sampling operations of the input unit, output unit, and controller by introducing a master clock that generates a common sampling clock signal. This unified timing mechanism ensures all components sample at the same moments, eliminating the alignment issues between trace function data and actual I/O signals while maintaining system modularity.
Solution Approach 2:
The patent introduces a sampling clock signal as an intermediary element that coordinates the sampling timing across all system components. This clock signal acts as a mediator that synchronizes the independent sampling operations of the input unit, output unit, and controller, enabling accurate temporal alignment without direct coupling between components.
2Measurement precision
If devices are adjusted after the control system is completed to improve accuracy, then the system can be optimized, but the adjustment process becomes complex and time-consuming due to the need to manually align sampling data with actual signals
Solution Approach 1:
The patent implements preliminary synchronization by establishing a common sampling clock mechanism before any adjustment operations are performed. This pre-alignment of sampling timing across all components eliminates the need for complex post-adjustment alignment procedures, allowing rapid and accurate device adjustments to be made at any stage of system operation.
3Ease of operation
If the sampling timing for internal variables is independent from actual I/O signal sampling, then each component can operate autonomously, but the ability to compare and analyze the relationship between internal variables and actual signals is compromised
Solution Approach 1:
The patent creates equipotential timing conditions across all system components by using a common sampling clock derived from a master clock. This ensures that the input unit, output unit, and controller all operate at the same timing potential, maintaining their autonomous functional independence while ensuring their sampling operations are temporally synchronized for accurate correlation analysis.
Data Source
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AI summary
A control system easily adjusts devices. In a control system (100), an input unit (13) included in a PLC system (1) obtains actual sampling data (1137b). An output unit (15) outputs an output signal based on output instruction data including a designated output timing and a designated output signal value. A task execution unit (1111) included in a controller (11) repeatedly executes a task in a predetermined period. A sampling unit (1113) obtains variable sampling data (1137a). A same time-series data generation unit (313) included in a development support apparatus (3) generates same time-series data. A same time-series data display unit (315) displays the same time-series data on the same time axis.