PLC Analog Input Signal Equalization Using Dynamic Error Correction
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Solution Overview
Problem
Existing analog input modules in PLCs face challenges in accurately measuring analog input signals due to hardware errors, particularly with nonlinear signals, and existing correction methods are time-consuming and inefficient for adaptive environments.
Innovation Solution
An apparatus and method that includes an error calculation unit, estimation parameter calculation unit, and error correction unit to equalize the PLC input signal to a reference signal using transfer functions, allowing for adaptive correction of signal errors based on ambient environment variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linear equation-based signal correcting scheme is used to measure the analog input signal several times, then the measurement accuracy is improved, but the time consumption increases significantly
Solution Approach 1:
The patent changes the correction parameters dynamically based on signal characteristics. Instead of using fixed linear correction parameters, the system adapts parameters according to the actual signal properties, enabling accurate correction in fewer measurements. This resolves the contradiction by maintaining high measurement accuracy while reducing the number of repeated measurements needed.
Solution Approach 2:
The patent replaces the mechanical repeated measurement approach with a computational correction method. Instead of physically measuring the signal multiple times through hardware loops, the system uses algorithmic processing to achieve the same correction effect in a single measurement, thereby eliminating time loss while maintaining precision.
2Ease of operation
If a linear equation-based correction method is used, then the correction process is simple, but it cannot handle nonlinear analog input signals
Solution Approach 1:
The patent introduces dynamic adaptation into the correction process. The correction algorithm automatically adjusts its behavior based on the input signal characteristics, switching between linear and nonlinear correction modes as needed. This maintains operational simplicity for the user while enabling handling of both linear and nonlinear signals through automated dynamic adjustment.
Solution Approach 2:
The correction system performs self-identification of signal types and self-adjustment of correction parameters without external intervention. The algorithm automatically detects whether the input signal is linear or nonlinear and applies the appropriate correction method, eliminating the need for manual configuration while expanding versatility to handle various signal types.
3Ease of manufacture
If hardware components like resistors and amplifiers are used in the analog input module, then the basic measurement function is achieved, but hardware errors cause measurement inaccuracies
Solution Approach 1:
The patent introduces a software correction algorithm as an intermediary between the hardware measurement and the final result. The hardware components continue to perform their basic measurement function, while the correction algorithm acts as a mediator that compensates for hardware errors through computational adjustment, thereby maintaining both ease of manufacture and measurement precision.
Solution Approach 2:
The system implements a feedback mechanism where the measured signal is processed through correction algorithms that use reference information to identify and compensate for hardware-induced errors. This feedback loop continuously adjusts the measurement results to account for hardware imperfections, maintaining high precision while using standard, easily manufactured hardware components.
Data Source
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AI summary
Disclosed are an apparatus and a method for controlling a signal such that a PLC input signal is equalized to a reference input signal. The apparatus includes an error calculation unit to calculate an error by using the PLC input signal and the reference input signal; an estimation parameter calculation unit to calculate an estimation parameter by using the reference input signal, the PLC input signal and the error; and an error correction unit to correct the error by using the estimation parameter such that the PLC input signal is equalized to the reference input signal.