PLC Signal Tracing With In-Cycle Change Sequence Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current tracing apparatuses using programmable logic controllers (PLCs) cannot determine the sequence of signal changes within a cycle from tracing results, as they treat signal changes at the same timing as simultaneous, making it difficult to analyze signal correlations.
Innovation Solution
A tracing apparatus connected to a PLC that includes a constituent element setting unit, tracing data acquisition unit, section detection unit, change sequence calculation unit, and change sequence output unit to detect and calculate the sequence of signal changes within a sampling cycle, allowing for the explicit output of change sequences alongside tracing data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If signal changes within a sampling cycle are treated as simultaneous, then the tracing apparatus can operate with simple timing handling, but the sequence of signal changes cannot be determined
Solution Approach 1:
The patent segments the sampling cycle into multiple time zones based on the timing of signal changes. By dividing the cycle into distinct segments (e.g., first time zone, second time zone), the system can track and record the sequence of signal changes within each segment while maintaining the overall simplicity of the tracing operation. This allows the tracing apparatus to preserve temporal information without complicating the basic timing handling mechanism.
2Measurement precision
If the tracing apparatus records all signal changes with detailed timing, then the sequence of signal changes can be determined, but the complexity of the tracing system increases
Solution Approach 1:
The patent introduces a temporal dimension by organizing signal change data into time zones within the sampling cycle. Instead of simply recording signal states, the system adds a time zone identifier to each signal change record, creating a multi-dimensional data structure that preserves sequencing information. This approach maintains relatively simple hardware while achieving precise timing measurement through intelligent data organization and processing.
3Ease of manufacture
If signal changes are sampled at fixed intervals, then the tracing apparatus can operate with simple sampling logic, but signal changes occurring between sampling points cannot be detected
Solution Approach 1:
The patent implements preliminary detection mechanisms that monitor for signal changes between formal sampling points. By using interrupt-based detection or edge-triggered monitoring, the system can identify signal changes that occur between regular sampling intervals and record them with appropriate time zone assignments. This ensures reliable detection of all signal changes while maintaining the simplicity of the fixed-interval sampling framework.
Data Source
AI summary
A tracing apparatus communicably connected to a programmable logic controller (PLC) that inputs and outputs a signal based on a ladder program, includes a constituent element setting unit configured to set a plurality of constituent elements to be traced among the constituent elements of the ladder program, a tracing data acquisition unit configured to acquire tracing data indicating a signal state of the constituent element at a specified timing, at a predetermined sampling cycle, a section detection unit configured to detect a sampling cycle section in which two or more of the acquired tracing data corresponding to the constituent elements simultaneously change, a change sequence calculation unit configured to calculate change sequence of signals of the constituent elements simultaneously changing in the detected sampling cycle section, and a change sequence output unit configured to output the calculated change sequence of the signals of the constituent elements.