Safety Sensor Muting by Learned Time-Window Signal Matching
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Solution Overview
Problem
Existing monitoring devices for hazardous areas, particularly those using light curtains, face issues with unnecessary machine standstill due to incorrect detection of permissible objects, complex and error-prone muting sensor coordination, and significant space usage by muting sensors.
Innovation Solution
A monitoring device that employs an external unit to generate control signals based on signal beginnings and ends from the safety sensor, determining muting conditions within a predetermined time window, eliminating the need for separate muting sensors and allowing for precise adaptation to operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If muting sensors are arranged upstream of the safety sensor to detect permissible objects, then unnecessary machine standstill is avoided, but device complexity and space usage increase significantly
Solution Approach 1:
The patent merges the muting function with the safety sensor itself by using the safety sensor to detect both safety-critical objects and permissible objects. The control unit integrates the logic to distinguish between these object types based on detection patterns, eliminating the need for separate muting sensors and their associated coordination systems.
Solution Approach 2:
The safety sensor is made multi-functional by enabling it to perform both its primary safety monitoring function and the additional function of detecting permissible objects for muting purposes. This universal approach allows one sensor to fulfill multiple roles, reducing overall device complexity while maintaining productivity.
2Reliability
If muting sensors are used to distinguish permissible objects, then safety function is prevented from triggering unnecessarily, but coordination complexity and error probability increase
Solution Approach 1:
The patent combines the detection and evaluation functions into a single integrated system. The control unit receives signals from the safety sensor and implements the muting logic internally, eliminating the complex coordination between multiple independent muting sensors and the safety sensor that characterized previous solutions.
Solution Approach 2:
The system uses feedback from the safety sensor's detection signals to dynamically control the muting state. The control unit continuously monitors the safety sensor output and adjusts the muting function accordingly, creating a closed-loop system that improves reliability while simplifying the overall architecture compared to open-loop coordination of multiple sensors.
3Adaptability or versatility
If light barrier arrangements are used as muting sensors, then permissible objects can be detected, but detection reliability is insufficient
Solution Approach 1:
The safety sensor is configured to perform multiple detection functions - both safety monitoring and permissible object detection - with a single device. This multi-functional approach maintains the high reliability of the safety sensor while adding detection versatility, avoiding the unreliable detection of specialized light barrier muting 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
This solution prevents unnecessary system shutdowns, reduces complexity and error in muting operations, and optimizes space usage by integrating muting functionality directly into the safety sensor's control signals, enhancing security and reliability.
Implementation Method 1
The monitoring device typically has a light curtain as a safety sensor, with which a protective field lying in one plane is monitored
Implementation Method 2
a transit time device for detecting a distance to the object and/or a size of the object
Data Source
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AI summary
The invention relates to a monitoring device (1) with a safety sensor (6) configured to monitor a protective field such that it generates a switching signal depending on object detections within the protective field. In the event of an object intrusion, a signal indicating a protective field violation is generated as the switching signal. An external unit generates a control signal with an inactive and an active signal state. A monitoring device serves as a muting condition to check whether the signal start and/or signal end of the protective field violation signal and the active control signal lie within a predetermined time window (Z1). The parameters defining the time window (Z1) are determined in a learning process. The invention further relates to a corresponding method.