RF Diagnostic Coverage for Wireless Proximity Stop Zones

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Solution Overview

Problem

Existing wireless Emergency Stop systems are inadequate for large installations where continuous communication between PSDs and MSDs is not feasible, leading to unacceptably stopping machine operations outside the PSD's range, and lack the ability to distinguish between MSDs in proximity and those not posing danger to the user.

Innovation Solution

Implementing diagnostic coverage in RF communication systems for PSDs and MSDs with Category 3 architecture to verify data and power levels, allowing MSDs to operate as beacons within a defined proximity without continuous communication, and ensuring safe operation through defined proximity detection and secure delinking protocols.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous communication between PSDs and MSDs is required for safety, then functional safety is improved, but machine operations stop unnecessarily when MSDs move outside communication range

Engineering Contradiction:

Improvefunctional safetyVSAvoidmachine operation continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary action by establishing safety parameters and proximity thresholds in advance. MSDs are pre-configured with safety zones and communication requirements, allowing the system to determine safety status based on pre-established criteria rather than requiring continuous active communication. This enables machines to operate safely when MSDs are outside communication range but still within defined safety zones.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of continuous communication, the system uses periodic action by implementing scheduled diagnostic checks and status verification at defined intervals. This reduces communication overhead while maintaining safety assurance, allowing machines to continue operation between periodic safety verifications when MSDs are outside continuous communication range.

Inventive Principle:

Principle #19Periodic action

2Adaptability or versatility

If wireless communication range is extended to cover large installations, then operational flexibility is improved, but reliability of safety communication deteriorates due to signal interference and loss

Engineering Contradiction:

Improveoperational flexibilityVSAvoidsafety communication reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system applies local quality by implementing localized safety zones around each MSD rather than relying on broad-area continuous communication. Each MSD defines its own safety perimeter with specific communication requirements, allowing the system to maintain high reliability locally while providing overall operational flexibility across large installations. This localized approach reduces the impact of signal interference on overall system reliability.

Inventive Principle:

Principle #3Local quality

3Reliability

If hardwired Emergency stop stations are used, then safety reliability is improved, but response time deteriorates due to operator movement requirements

Engineering Contradiction:

Improvesafety reliabilityVSAvoidemergency stop response time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system replaces the mechanical approach of hardwired stop stations requiring operator movement with a wireless electronic system. PSDs and MSDs use wireless communication to transmit stop commands instantly, eliminating the time required for operator physical movement while maintaining safety reliability through electronic verification and diagnostic coverage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If diagnostic coverage is implemented in RF communication, then functional safety is improved, but device complexity increases due to Category 3 architecture requirements

Engineering Contradiction:

Improvefunctional safetyVSAvoidcommunication system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system applies partial action by implementing diagnostic coverage at critical points in the communication architecture rather than throughout the entire system. Category 3 architecture requirements are applied selectively to key components where diagnostic coverage provides the most safety benefit, reducing overall device complexity while maintaining functional safety.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20250240665A1Radio frequency (RF) diagnostic coverage for wireless proximity stop systems and corresponding methods of operating wireless proximity stop systems

Publication Date: 2025.07.24 CATTRON NORTH AMERICA INC

AI summary

A wireless Proximity Stop system includes one or more Machine Safety Devices (MSDs) and one or more Personal Safety Devices (PSDs). Each MSD includes a wireless communication interface with Diagnostic Coverage (DC). Each PSD includes a wireless communication interface with Diagnostic Coverage (DC) for wireless communication with the one or more MSDs. Each PSD is configured to be operable for initiating and safely terminating a Proximity Stop signal to the one or more MSDs to trigger a Proximity Stop function of the one or more MSDs for stopping operation of a connected machine(s). Each PSD includes a transmitter and separate receiver operable for verifying that the transmitter is transmitting with the correct data and power level. Each MSD includes a receiver and a separate transmitter or local transmitting beacon usable by the receiver for verifying that the receiver is capable of receiving with the correct data and power level.