Timestamp Query Coupling for Multi-Database PLC Data Alignment
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Solution Overview
Problem
In factory automation systems, the differing time stamp cycles of data collected by PLCs with varying frequencies pose challenges when coupling data from multiple databases, leading to inconsistencies and difficulties in aligning timestamps for accurate data integration.
Innovation Solution
A control system that includes a query processor to analyze and adjust the accuracy of timestamps, allowing for the creation of individual queries for each database, processing and coupling data to align timestamps to a designated accuracy, and converting data into average, largest, or smallest values to synchronize data collection cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If data is collected with high frequency and high accuracy time stamps, then measurement precision is improved, but device complexity increases and difficulty of coupling data from multiple databases worsens
Solution Approach 1:
The patent changes the parameter of time stamp accuracy by allowing different databases to operate at different precision levels (e.g., 1μs for PLC1, 1ms for PLC2) while introducing a normalization mechanism that converts these different precision levels to a common basis for coupling, thus maintaining high measurement precision without increasing overall system complexity
Solution Approach 2:
The patent introduces an intermediary coupling mechanism that mediates between databases with different time stamp accuracies. This intermediary performs timestamp normalization and data alignment, allowing high-precision data to be coupled with lower-precision data without requiring all databases to operate at the same high precision level
2Adaptability or versatility
If different PLCs collect data with different cycles, then adaptability is improved, but the ability to couple databases worsens due to mismatched time stamp cycles
Solution Approach 1:
The patent allows each PLC to operate with its own data collection cycle parameter (e.g., 1μs for PLC1, 1ms for PLC2) while introducing a normalization process that adjusts these different cycles to a common reference frame, thus maintaining adaptability while ensuring coupling reliability
Solution Approach 2:
The patent implements a dynamic coupling mechanism that can adapt to different data collection cycles. The system dynamically adjusts the normalization factor based on the specific cycle of each database, allowing flexible coupling of databases with varying collection frequencies without compromising consistency
3Measurement precision
If high accuracy time stamps with many significant figures are used, then measurement precision is improved, but loss of time increases due to processing overhead
Solution Approach 1:
The patent changes the precision parameter dynamically based on the specific coupling scenario. Instead of always using maximum precision (many significant figures), the system selects an appropriate precision level for each coupling operation, reducing unnecessary processing overhead while maintaining sufficient accuracy for the task at hand
Data Source
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AI summary
A plurality of databases can be coupled after aligning time stamp cycles of data of the databases. An item (LEVEL) for designating a time stamp accuracy is added to an inquiry syntax (SQL syntax) of a query. At the time of table coupling, a query designating the desired accuracy in LEVEL is transmitted. This query is analyzed by a query purser 101b, and individual queries are created for each database targeted for inquiry and transmitted. At the time of coupling acquired tables, the number of digits of the time stamps is adjusted to be the same in accordance with the designated accuracy, and the tables are coupled in chronological order of the time stamps.