Inductive Proximity Sensor Synchronization Against Coil Crosstalk
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Solution Overview
Problem
Inductive proximity sensors experience interference and synchronization issues when operated in close proximity due to crosstalk between sensor coils, leading to measurement errors and reduced measuring rates.
Innovation Solution
A synchronization method using a synchronization line to coordinate the operation of multiple proximity sensors, ensuring that pulse evaluation processes are synchronized to avoid interference by delaying operations until neighboring sensors are not active.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple inductive proximity sensors are operated in close proximity using pulse evaluation method, then measurement capability is improved, but mutual interference between sensor coils causes measurement errors
Solution Approach 1:
The patent applies periodic action by implementing cyclic current pulses with synchronized timing for multiple sensors. The control units coordinate their pulse evaluation processes to occur at different phases within a synchronized period, ensuring that when one sensor applies an excitation pulse, neighboring sensors are in their evaluation phase and thus not affected by interference voltages.
Solution Approach 2:
The synchronization mechanism uses feedback from the clock sources of control units to adjust and maintain synchronized operation. The control units monitor each other's pulse evaluation status and adjust their timing accordingly, creating a feedback loop that ensures reliable coordination and prevents mutual interference while maintaining measurement capability.
2Reliability
If sensors are synchronized to avoid interference, then measurement reliability is improved, but measuring rate is reduced due to coordinated timing
Solution Approach 1:
The system maintains high measuring rates by implementing periodic synchronized pulse evaluation cycles. Within each synchronized period, multiple sensors can operate at different phases, allowing frequent measurements across the sensor array while maintaining reliability through coordinated timing that prevents interference.
3Ease of operation
If phase position is fixed to prevent interference, then signal evaluation is simplified, but synchronization cannot be guaranteed when minimum distance is exceeded
Solution Approach 1:
The patent implements dynamic synchronization where the phase positions of pulse evaluation processes can adjust within a synchronized framework. The control units maintain synchronization through coordinated timing while allowing flexible phase positioning that adapts to varying sensor distances and configurations, ensuring reliable operation whether sensors are at minimum or maximum distances.
Solution Approach 2:
The synchronization mechanism uses feedback from clock sources to dynamically adjust and maintain coordinated operation. This feedback-based approach ensures that phase positions remain synchronized even when sensor distances vary, maintaining both signal evaluation simplicity and synchronization reliability across different operating conditions.
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
Prevents interference during voltage measurements, maintaining high measuring rates and ensuring reliable operation of inductive proximity sensors in close proximity without requiring a minimum distance.
Implementation Method 1
A current pulse is applied to a sensor coil, and the voltage response is evaluated. The voltage response varies due to the induction of eddy currents in the object to be detected
Implementation Method 2
The voltage response varies due to the induction of eddy currents in the object to be detected
Implementation Method 3
If the sensor coils of the proximity sensors are arranged close to one another, a magnetic coupling with a non-negligible coupling factor exists between the sensor coils
Implementation Method 4
a time-varying magnetic field caused by one of the sensor coils can induce interference voltages in the sensor coil of another proximity sensor
Data Source
Figure 1
Figure 2a~2e
Figure 3
AI summary
The invention relates to an inductive proximity sensor (1) comprising: - a sensor coil (2), - a pulse evaluation circuit (3) which is designed to provide an excitation pulse for the sensor coil (2) and to obtain a resulting voltage response; - a control unit (4) which is designed to control the pulse evaluation circuit (3) according to a pulse evaluation method such that the sensor coil (2) is excited with an excitation pulse of a predetermined duration;o to detect at least a first measurement voltage at a specific first point in time after providing the excitation pulse, and o to provide an indication of the presence or absence of an object (10) to be detected in a detection area around the sensor coil (2), wherein a synchronization unit (7) is provided to receive a synchronization signal indicating whether or when a pulse evaluation method is active in an adjacent proximity sensor, and that the control unit (4) is designed to start the pulse evaluation method depending on the synchronization signal.;