Variable-Impedance Digital Input for Reliable Binary Signal Sensing

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Solution Overview

Problem

Digital contact transducers in polluted and moist environments suffer from low parasitic resistances, leading to false signal detection and unwanted shutdowns in power transmission systems, while high-impedance digital inputs face power losses and slow signal detection.

Innovation Solution

A device and method utilizing a variable input impedance to adapt to actual signal levels, with low impedance for low signal levels and high impedance for high signal levels, controlled using a bipolar transistor and resistor with pulse width modulation, to enhance sensing reliability and minimize power dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If low-impedance digital inputs are used to improve signal detection reliability in polluted environments, then false detections are reduced, but power losses increase

Engineering Contradiction:
Improvesignal detection reliabilityVSAvoidpower losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the input impedance variable rather than fixed. The impedance adapts dynamically based on the detected signal level: low impedance is used when signal levels are low to improve detection reliability, and high impedance is used when signal levels are high to reduce power consumption. This dynamic adjustment resolves the contradiction between reliability and energy loss.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the impedance parameter based on signal level conditions. By monitoring the signal level and adjusting the impedance parameter accordingly (low impedance for low signal levels, high impedance for high signal levels), the system optimizes both detection reliability and power efficiency under different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If high-impedance digital inputs are used to reduce power losses, then power consumption decreases, but signal detection becomes slow

Engineering Contradiction:
Improvepower lossesVSAvoidsignal detection speed
Core Design Contradiction:
Loss of energyVSSpeed

Solution Approach 1:

The system dynamically adjusts impedance based on signal level: high impedance is used during normal high signal levels to minimize power consumption, while low impedance is activated when low signal levels are detected to ensure fast and reliable detection. This dynamic switching resolves the speed-power tradeoff.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The impedance parameter is changed based on signal level conditions. High impedance is maintained for power efficiency during normal operation, but the parameter is switched to low impedance when detection of weak signals is required, ensuring both power efficiency and detection speed are optimized at different times.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If fixed low-impedance inputs are used to improve detection reliability, then false detections are reduced, but the system cannot adapt to varying signal conditions

Engineering Contradiction:
Improvedetection reliabilityVSAvoidadaptability to signal levels
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamics by making the input impedance adaptive rather than fixed. The impedance automatically adjusts based on the detected signal level, providing low impedance for reliable detection of weak signals and high impedance for power efficiency with strong signals, thus achieving both reliability and adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The impedance parameter is dynamically changed based on signal level conditions. The system monitors signal levels and adjusts the impedance parameter accordingly, enabling the system to adapt to varying signal conditions while maintaining detection reliability across different operating environments.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2616826B1Digital input with variable impedance
Publication Date: 2014.11.12 ABB TECHNOLOGY AG
  • EP2616826B1 patent drawingFigure 1
  • EP2616826B1 patent drawingFigure 2
  • EP2616826B1 patent drawingFigure 3

AI summary

A device (400) for sensing a binary signal (450) is provided. The device comprises means (410) for measuring a signal level of the signal, means (420) for determining whether the measured signal level is "low" or "high", means (430) for providing a variable input impedance, and means (440) for controlling the input impedance in response to the measured signal level. The variable input impedance may be provided by way of a transistor (T) and a resistor (R), and by controlling the duty ratio of the transistor using pulse width modulation. Preferably, the input impedance is controlled to be low for low signal levels and to be high for high signal levels, which results in a more reliable sensing of binary signals. The device may be used for detecting the state of contact transducers suffering from parasitic resistances caused by moist and/or polluted environments. Further, a method of sensing a binary signal is provided.