Light Grid With Coded Beam Synchronization
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Solution Overview
Problem
Existing light grids face challenges in ensuring fail-safe operation with low circuit complexity, particularly in safety engineering, and are limited in synchronizing with multiple beam axes, leading to reduced operational availability and increased circuit complexity.
Innovation Solution
A light grid design where transmitters emit uniquely coded light beams, and receivers are activated in parallel to an evaluation unit with a two-channel microcontroller structure, allowing for fail-safe operation and synchronization with any beam axis, eliminating the need for complex shift registers and reducing circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclically activated photodiodes synchronized with a selected transmitter are used, then synchronization and error detection are achieved, but the circuit complexity increases undesirably for safety engineering applications
Solution Approach 1:
The patent extracts the complex cyclic activation and synchronization logic from the receiver side and relocates it to the transmitter side. The transmitters are activated cyclically with unique identifiers, while receivers remain continuously active and simply evaluate incoming signals. This extraction reduces receiver circuit complexity while maintaining reliable operation through the embedded identifier-based synchronization mechanism.
Solution Approach 2:
The patent introduces unique identifiers as an intermediary mechanism that mediates between transmitters and receivers. Each transmitter is assigned a distinct identifier that is transmitted with its light beams. Receivers use these identifiers to determine which transmitter is currently active and to synchronize evaluation accordingly, eliminating the need for complex cyclic activation circuits while ensuring reliable operation.
2Adaptability or versatility
If beam axes are permanently interrupted for muting or blanking functions, then safety zones can be created, but the light grid can no longer be synchronized with the selected transmitter
Solution Approach 1:
The patent implements a feedback mechanism where receivers continuously monitor incoming light beams and evaluate their identifiers. Even when beam axes are permanently interrupted for blanking functions, the system maintains synchronization capability because the identifier-based recognition allows the evaluation unit to identify which transmitters are active and which beam axes are intentionally muted, enabling proper synchronization without requiring all beam axes to be functional.
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 design ensures reliable, cost-effective, and fault-tolerant operation by integrating safety functions in the evaluation unit, allowing for synchronization with any beam axis and reducing the risk of errors, thereby increasing the light grid's availability and safety in safety technology applications.
Implementation Method 1
transmitters emitting transmitted light beams with a receiver unit with a number of receivers
Implementation Method 2
receivers receiving received light beams
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a light grid (1) for detecting objects in a monitoring area with a predetermined number of emitting light beams (2) emitted by transmitters (3) and receivers (6). Each transmitter (3) and its associated receiver (6) form a beam axis. In an evaluation unit, an object detection signal is generated depending on the received signals present at the outputs of the receivers (6). The individual transmitters (3) are activated cyclically, one after the other, with uniquely identifying codes imprinted on the emitted light beams (2) of each transmitter (3). The receivers (6) are activated simultaneously, with their received signals being fed in parallel to separate inputs of the evaluation unit.In the evaluation unit, only the received signals of the receiver (6) assigned to the currently active transmitter (3) are registered and stored by muting the inputs to which the received signals of the other receivers (6) are routed. The evaluation unit then checks the correctness and sequence of the codes transmitted by the transmitters (3) by analyzing the stored received signals.