Input Module Error Detection Using Series Resistors
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Solution Overview
Problem
Existing input modules in automation technology fail to detect errors occurring within multiplexers, which are critical for ensuring fail-safe acquisition of analog signals such as pressure, temperature, and flow rate, due to lack of error detection mechanisms.
Innovation Solution
Incorporating series resistors between multiplexers and analog-to-digital converters to create a voltage difference, allowing for error detection by evaluating asymmetry in the voltage mesh, and using a microcontroller to compare digitized input values for fault identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If series resistors are added to the input channels, then error detection capability is improved, but device complexity increases
Solution Approach 1:
Series resistors are introduced as intermediary elements between the multiplexer and the analog-to-digital converter. These resistors create a measurable voltage difference when current flows through them, enabling error detection in the multiplexer without fundamentally changing the core conversion function. The resistors act as mediators that translate potential errors into detectable voltage variations.
Solution Approach 2:
The invention changes the electrical parameters of the input channel by adding series resistors, which modifies the voltage-current relationship in the circuit. This parameter change enables the detection of errors through voltage measurements while maintaining the overall functionality of the input module. The resistors create a controlled voltage drop that serves as an error indicator.
2Measurement precision
If redundant input channels are used for error detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The first input channel is used as a reference or copy of the expected correct behavior. By comparing the output of the first channel with the second channel, the system can detect errors in the second channel without requiring a completely separate testing mechanism. The first channel serves as a template for what the second channel should produce under identical conditions.
Solution Approach 2:
The system implements feedback by continuously monitoring and comparing the outputs of multiple input channels. When a discrepancy is detected between channels, the system can identify potential errors and take corrective action. This feedback mechanism enables real-time error detection while utilizing existing hardware resources efficiently.
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
Enhances error detection capabilities by identifying interruptions, short circuits, or common cause errors in multiplexers, thereby increasing the reliability of analog signal acquisition and ensuring fail-safe operation.
Implementation Method 1
A current flowing through the series resistance results in a voltage drop across this series resistance and thus influences the symmetry of the voltage loop or it ensures a difference between the first input value and the second input value
Data Source
AI summary
The module (1) has input channels (2a, 2b) i.e. potential dividers (4a, 4b), attached to multiplexers (5a, 5b). The multiplexer (5a) is connected with two analog-digital converters (6a, 6b) such that a measuring signal (3a) lies at the converters as digitized input values, respectively, where switches (S1-S6) e.g. transistors, of the multiplexer (5a) are connected to determine the signal. Longitudinal resistors (8) forming a difference between the input values are arranged between the channels and the converters. A microcontroller (9) is connected with the converters to compare the values. An independent claim is also included for a method for recognizing errors in an input module for acquisition of analog measuring signals.