Modular Hall Sensor System for Pneumatic Cylinder Position Detection

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Solution Overview

Problem

Existing magnetic sensors for piston position detection in pneumatic cylinders are limited by high costs, large installation space, and high power consumption due to the use of numerous field line sensitive sensor elements and complex control electronics, which restrict their compact design and measuring range.

Innovation Solution

A magnetic sensor design featuring Hall sensors connected to control electronics via a serial shift register, allowing for parallel activation and direct connection to an analog Hall signal bus line, enabling a compact, cost-effective, and scalable solution with reduced power consumption and expanded measuring range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a large number of sensor elements are used to increase measuring range, then the measuring range is improved, but the installation space and device complexity increase

Engineering Contradiction:
Improvemeasuring rangeVSAvoidinstallation space
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The sensor system is divided into multiple independent modules, each containing a limited number of sensor elements (e.g., 8 Hall sensors per module). These modules can be cascaded together to achieve the desired measuring range. Each module has its own control electronics and can be independently addressed, allowing the system to scale from a few centimeters to several meters without requiring a single large complex circuit board.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a two-dimensional array of sensors on a single circuit board to a one-dimensional linear arrangement of cascadable modules. This modular linear structure allows the measuring range to be extended along the length of the sensor assembly rather than requiring a large area on a single board, effectively converting an area problem into a length problem that can be solved by adding modules in series.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If many sensor elements are activated in parallel to improve response time, then the response time is improved, but the power consumption increases

Engineering Contradiction:
Improveresponse timeVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

Instead of continuously activating all sensor elements or using complex parallel activation schemes, the patent employs periodic scanning of sensor elements within each module. The control electronics sequentially activate and read signals from individual Hall sensors in a time-multiplexed manner. This periodic activation reduces average power consumption while maintaining adequate response time for piston position detection in pneumatic cylinders.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The sensor system dynamically adjusts which sensor elements are active based on the detected position. The control electronics can selectively activate only the relevant subset of Hall sensors needed for the current measurement range, rather than keeping all sensors continuously active. This dynamic activation pattern optimizes the balance between response time and power consumption.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If complex control electronics with address circuits and multiplexers are used to manage many sensor elements, then the control capability is improved, but the installation space and cost increase

Engineering Contradiction:
Improvecontrol capabilityVSAvoidinstallation space
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Each module in the cascaded system uses a universal control architecture based on shift registers that can address multiple sensor elements within that module. The same control electronics design can be replicated across all modules, providing multi-functionality and adaptability. The shift register-based addressing scheme is versatile enough to handle any number of modules by simply extending the cascade, without requiring different control electronics for different configurations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extracts the complex address circuit and multiplexer functionality from a centralized location and distributes it across multiple simple modular units. Each module contains only the minimal control electronics needed to manage its local sensor elements (shift registers and basic multiplexing), while the overall system addressing is achieved through the cascaded module structure. This extraction of complexity from the center to the edges simplifies each individual module.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If sensor elements are permanently supplied with voltage to simplify control, then the control simplicity is improved, but the self-heating and power consumption increase

Engineering Contradiction:
Improvecontrol simplicityVSAvoidself-heating
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The Hall sensor elements are not permanently supplied with voltage but are instead activated periodically through the shift register control system. Each Hall sensor receives power only when its corresponding bit in the shift register is set to activate it, and remains in a low-power state otherwise. This periodic activation dramatically reduces average power consumption and self-heating while maintaining the ability to quickly activate sensors when needed for measurement.

Inventive Principle:
Principle #19Periodic action

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

The solution allows for a compact, cost-effective, and scalable magnetic sensor system with a theoretically arbitrary measuring length, precise position determination, and reduced power consumption, suitable for compact applications like pneumatic cylinders.

Implementation Method 1

The magnetic sensor according to the invention for determining a position of a transmitter magnet (12) along a path has a plurality of Hall sensors (20) connected to control electronics (22)

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP2166313B1Magnetic sensor
Publication Date: 2011.11.09 SICK AG
  • EP2166313B1 patent drawingFigure 1~2
  • EP2166313B1 patent drawingFigure 3
  • EP2166313B1 patent drawingFigure 4~5

AI summary

The sensor (10) has a control logic (22) for receiving a sensor element signal of one of sensor elements (20) i.e. Hall sensor. A signal line is provided for transmitting the signal to an evaluation unit (30) to evaluate the signal and to determine position (C) of a sensor magnet (12). The control logic serially receives control data for the sensor element to be activated, and directly activates the sensor element parallel and corresponding to a controller. The elements are directly connected to the line formed as a hall signal-bus line. An independent claim is also included for a method for determining position of a sensor magnet.