Proximity Switch Speed Measurement via Resonant Thresholds
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Solution Overview
Problem
Existing proximity switches lack the capability to accurately determine the speed of a measuring object moving in the axial direction with minimal circuit complexity.
Innovation Solution
A proximity switch with a resonant circuit and oscillation amplifier that generates multiple switching signals based on varying resonant impedance due to the object's distance, using timers and speed calculation units to derive speed and acceleration information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate sensor system (light barrier unit) is used to determine speed, then speed measurement capability is improved, but device complexity increases
Solution Approach 1:
The patent combines the speed measurement function with the proximity switch by using the existing oscillating circuit to generate multiple switching signals at different threshold levels. The evaluation unit processes these signals to calculate speed, merging what would traditionally require separate sensors into a single integrated device.
Solution Approach 2:
The proximity switch is enhanced to perform multiple functions: traditional proximity detection and new speed measurement capability. The oscillating circuit serves dual purposes by providing both proximity switching signals and timing signals for speed calculation, making the device universal.
2Measurement precision
If multiple sensor elements with spatially distributed detection ranges are used to detect direction and speed, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The detection range is segmented into multiple threshold levels within a single sensor element. Instead of using multiple spatially distributed sensor elements, the patent divides the detection range of one element into several zones defined by different threshold values, achieving the same effect with simpler hardware.
Solution Approach 2:
The patent transitions from spatial distribution of multiple sensor elements to temporal distribution of switching signals. By evaluating switching signals at different threshold levels occurring at different times, the system extracts speed and direction information without requiring multiple spatially separated sensors.
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
Enables efficient and accurate determination of object speed and acceleration with reduced circuit complexity by evaluating oscillation parameters and time intervals between threshold crossings.
Implementation Method 1
at least one resonant circuit inductance (L) is designed to interact with a measurement object (M) inductively such that a resonant impedance of the resonant circuit changes depending on a distance of the measurement object from the resonant circuit
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a proximity switch (1) for detecting a measurement object (M) in a detection range and for determining a speed value of the measurement object (M), comprising: - a resonant circuit (2) with at least one resonant circuit inductance (L) and at least one resonant circuit capacitance (C1, C2), wherein the at least one resonant circuit inductance (L) is designed to interact with a measurement object (M) such that the resonant impedance of the resonant circuit (2) changes depending on the distance of the measurement object (M) from the resonant circuit (2); - an oscillation amplifier (O) which forms an oscillator with the resonant circuit; - an oscillation measurement unit (3) for determining an oscillation measure;- a switching signal unit (4) configured to generate a first switching signal (S1) upon falling below or exceeding a first switching threshold (USP1, SW1) and a second switching signal (S2) upon falling below or exceeding a second switching threshold (USP2, SW2), which is different from the first; - a timer (5) configured to be started by the first switching signal (S1) and to be stopped by the second switching signal (S2), and to provide a time indication for the time interval between the first and the second switching signals (S1, S2); - a speed calculation unit (6) configured to provide a speed indication depending on the time indication.