Light Grid Synchronization Using Time-Offset Beams

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing light grid synchronization methods are costly and complex, often requiring multiple identifiers or complex control units, and can be disrupted by blanking areas, which affects the availability and reliability of the safety system.

Innovation Solution

A method using two synchronization transmission beams with a distinct identifier, allowing for time-based synchronization without the need for multiple identifiers or complex control units, enabling flexible and cost-effective implementation, and ensuring synchronization even if some transmitter/receiver pairs are hidden due to blanking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single transmitter/receiver pair is used for synchronization, then the system is simple to implement, but synchronization is disrupted when this pair is blanked out

Engineering Contradiction:
Improvesynchronization system complexityVSAvoidsynchronization availability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The synchronization function is segmented from a single dedicated transmitter/receiver pair and distributed across multiple transmitter/receiver pairs. Each pair can independently provide synchronization signals, ensuring that if one is blanked out, others can maintain synchronization. This is achieved by enabling any transmitter/receiver pair to transmit and detect synchronization beams with unique identifiers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Transmitter/receiver pairs are designed to serve dual functions: both safety monitoring and synchronization. By equipping all pairs with the capability to transmit and detect synchronization beams, the system eliminates the need for dedicated synchronization hardware, reducing complexity while improving reliability through redundancy.

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

2Measurement precision

If multiple identifiers are assigned to different transmitter/receiver pairs for synchronization, then unambiguous assignment is achieved, but production costs increase due to complex control units

Engineering Contradiction:
Improvesynchronization beam identification accuracyVSAvoidcontrol unit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of using multiple complex identifiers, the system changes the approach by using a single unique identifier that can be dynamically assigned to different transmitter/receiver pairs. The identification is achieved through time-based parameters (which pair transmits the synchronization beam) rather than complex multi-parameter identifiers, simplifying the control unit design while maintaining unambiguous identification.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If transmitter/receiver pairs are selectively blanked out to define safety-critical areas, then the protective field is adapted to actual monitoring needs, but synchronization is prevented in blanked areas

Engineering Contradiction:
Improveprotective field configuration flexibilityVSAvoidsynchronization availability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The synchronization function is segmented across multiple transmitter/receiver pairs rather than relying on a single pair. This segmentation allows the system to maintain synchronization capability in non-blanked pairs even when some pairs are blanked out for safety-critical area definition, ensuring both adaptability and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system prepares for potential blanking by distributing synchronization capability across multiple transmitter/receiver pairs in advance. This redundancy acts as a cushion against synchronization disruption, ensuring that if some pairs are blanked out, sufficient backup pairs remain available to maintain synchronization.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 approach simplifies and cost-reduces light grid synchronization, enhances availability by allowing synchronization with any transmitter/receiver pair, and improves reliability by using a binary sequence for easy identification and absolute assignment of synchronization beams.

Implementation Method 1

The transmitter of this transmitter/receiver pair emits a synchronization beam that is different from the other transmission beams

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 2

If the receiver receives the synchronization beam, the cyclical activation of the following receivers starts from this receiver

Methodology Applied
Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentEP3014313B1Method for synchronizing a light grid
Publication Date: 2021.04.07 PILZ AUSLANDSBETEILIGUNGEN
  • EP3014313B1 patent drawingFigure 1
  • EP3014313B1 patent drawingFigure 2
  • EP3014313B1 patent drawingFigure 3

AI summary

The invention relates to a light grid (10) which comprises a transmitting unit (20) having a plurality of transmitters (22), a receiving unit (24) having a plurality of receivers (26), a transmitter control unit (44), which activates the transmitters (22) in succession in a cycle (T), and a receiver control unit (32) for evaluating the receivers (26). Each receiver (26) is associated with a transmitter, and an activated transmitter (22) transmits a transmission beam (28) to the receiver (26). At least two transmission beams (28) in the cycle T are synchronization transmission beams (29), which are emitted at a time offset (D) from each other. The receiver control unit measures the time offset (D), wherein the synchronization transmission beams (29) are uniquely associated with the totality of the transmission beams (28) in the cycle (T) on the basis of the time offset (D).