Fail-Safe Access Control for Machine Operating Mode Selection

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Solution Overview

Problem

Existing safety systems for machines require complex and costly programming to manage operating modes and access control, especially for NC machines with limited memory, and lack the flexibility to adapt to different applications and ensure fail-safe operating mode selection.

Innovation Solution

A control device with an evaluation unit and acquisition units, including a reading unit and a safety controller, which are separate from the control system, with a fail-safe design, manages access control and operating mode selection independently, eliminating the need for complex programming and integrating an access control system into the control unit and integrating an access control system into the control unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the safety controller is integrated into the operating mode selection, then access control and operating mode selection can be managed in one system, but the programming becomes very complex and costly

Engineering Contradiction:
Improveoperating mode selection capabilityVSAvoidprogramming complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system is divided into two independent parts: the safety controller that handles safety functions, and the control device that handles access control and operating mode selection. This segmentation allows each component to be programmed for its specific function, reducing overall programming complexity while maintaining full functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The access control system and operating mode selection functionality are extracted from the safety controller and placed in a separate control device. This extraction eliminates the need to program complex access control logic into the safety controller, reducing programming complexity and cost.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If specialized security technology is used for operating mode selection, then security requirements are met, but the system complexity and cost increase

Engineering Contradiction:
Improvesecurity levelVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The access control system and operating mode selection system are merged into a single integrated control device. This combination maintains high security levels through authorized access control while reducing system complexity by eliminating the need for separate specialized security hardware and software components.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3779899B1Control device
Publication Date: 2026.01.07 EUCHNER GMBH & CO KG
  • EP3779899B1 patent drawingFigure 1
  • EP3779899B1 patent drawingFigure 2

AI summary

The invention relates to a control device (7) for a system controlled by a controller, comprising an evaluation unit (9) and at least one acquisition unit (17a, 17b) connected to the evaluation unit (9). Depending on the input variables entered into the acquisition unit (17a, 17b), an operating mode selection and/or access authorization can be performed in the evaluation unit (9). Output variables generated in this way can be output to the controller via an output stage (8).