Door Function Sensor Monitoring Against Magnetic Field Tampering
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Solution Overview
Problem
Existing door monitoring systems are vulnerable to manipulation by external magnetic fields, which can disrupt the functioning of door function units such as closers, drives, locks, or holding systems, compromising safety and reliability.
Innovation Solution
A monitoring device for door function units equipped with a sensor unit comprising a first magnetic sensor and an encoder, along with a second magnetic sensor to detect and differentiate between manipulative and non-manipulative external magnetic fields, ensuring accurate operation and tamper detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a first magnetic sensor is used to detect the position of a movable functional element, then the door function unit can be monitored for proper functioning, but the sensor can be disrupted by external magnetic fields (manipulative or non-manipulative)
Solution Approach 1:
A second magnetic sensor is introduced as an intermediary element to detect external magnetic fields. This sensor does not directly monitor the door function unit but rather monitors the environmental magnetic field conditions, serving as a mediator between the external environment and the first magnetic sensor's measurements.
Solution Approach 2:
The control arrangement uses feedback from the second magnetic sensor to continuously monitor external magnetic field conditions and adjusts the evaluation of the first magnetic sensor's signals accordingly. When external magnetic fields are detected, the system feedbacks this information to modify or invalidate the position measurements from the first sensor.
2Measurement precision
If the first magnetic sensor is arranged close to the encoder for accurate position detection, then measurement precision is improved, but the sensor becomes more vulnerable to external magnetic field manipulation
Solution Approach 1:
The second magnetic sensor acts as an intermediary that detects external magnetic fields before they can affect the first magnetic sensor's measurements. By monitoring the environmental conditions through this intermediate sensor, the system can compensate for or reject corrupted signals from the first sensor when external fields are present.
Solution Approach 2:
The solution adds a new dimension of monitoring by introducing the second magnetic sensor that detects external magnetic field conditions. This creates a two-dimensional monitoring approach: the first sensor monitors position along one dimension, while the second sensor monitors external field interference along another dimension, allowing the system to distinguish between valid position changes and external field disruptions.
3Device complexity
If no second magnetic sensor is used, then the device complexity is reduced, but the system cannot distinguish between manipulative and non-manipulative external magnetic fields
Solution Approach 1:
The monitoring function is segmented into two independent parts: the first magnetic sensor handles position detection, while the second magnetic sensor handles external field monitoring. This segmentation allows each sensor to specialize in one function, with the control arrangement integrating both functions to provide comprehensive monitoring and tamper detection capabilities.
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 system effectively monitors and detects proper functioning of the door unit, providing a reliable and secure operation of the door unit, ensuring accurate operation and safety and reliability of door function units by distinguishing between intentional and unintentional magnetic field interference.
Implementation Method 1
The first magnetic sensor is designed and arranged for detecting the encoder, particularly without contact. Most preferably, the first magnetic sensor is designed to detect the position and/or rotation and/or acceleration of the encoder.
Implementation Method 2
The at least one second magnetic sensor is designed and configured to monitor the operation of the first magnetic sensor by detecting an external magnetic field.
Data Source
Figure 1
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AI summary
The invention relates to a monitoring device (1) for a door function unit, in particular a door closer (2), door drive, door lock (106) or door holding system (105), comprising a sensor unit (10) designed for arrangement in the door function unit, with a first magnetic sensor (11) and an associated encoder (12), wherein the sensor unit (10) is designed and configured to detect a position of a movable functional element of the door function unit, and at least a second magnetic sensor (14) which is designed and configured to detect an external magnetic field for monitoring the operation of the first magnetic sensor (11).