Single-Bus Emergency Stop Control With Redundant Safety Switching
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Solution Overview
Problem
Existing drive systems with emergency stop switches face challenges in achieving high safety levels without unnecessary additional components, particularly in using a single-channel data bus for connecting electrical devices with two-channel emergency stop functionality.
Innovation Solution
A system where a single-channel data bus connects two electrical devices with a two-channel emergency stop switch, utilizing logic units to transmit and verify safety-related information packets with CRC checks, allowing for redundant switching and mutual monitoring between devices, thus achieving a higher safety category without additional safety devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-channel data bus is used to connect electrical devices, then device complexity and cost are reduced, but safety level deteriorates
Solution Approach 1:
The patent segments the data transmission into two independent logical channels over the single physical data bus. Each channel transmits safety-related information packets separately, allowing the system to achieve dual-channel safety functionality without requiring two separate physical data buses, thus reducing device complexity while maintaining safety levels
Solution Approach 2:
The single-channel data bus is made multi-functional by enabling it to carry two separate safety-related information streams simultaneously. The data bus performs the function of both Channel 1 and Channel 2 through proper signal routing and packet identification, eliminating the need for additional dedicated safety communication hardware
2Reliability
If additional safety devices are added to achieve high safety category, then safety level is improved, but device complexity and cost increase
Solution Approach 1:
The electrical devices utilize their existing logic units and computer units for mutual monitoring and safety verification. The system performs self-diagnosis and self-verification through CRC checks and cross-channel monitoring, eliminating the need for additional external safety devices or controllers
Solution Approach 2:
The safety monitoring and control functions are merged into the existing logic units and computer units of the electrical devices. The dual-channel emergency stop functionality is integrated into the standard device architecture, combining safety functions with existing control components rather than adding separate safety systems
3Reliability
If dual-channel emergency stop switch is implemented with separate hardware channels, then safety reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces the need for separate physical hardware channels with a digital communication approach over a single data bus. Safety-related information packets are transmitted electronically with proper signaling and verification, substituting mechanical/duplicate hardware pathways with intelligent software-controlled digital communication, thereby reducing manufacturing costs while maintaining safety integrity
Data Source
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AI summary
The invention relates to a system and method for operating a system with a controller connected to two electrical devices, in particular two electrical devices designed as bus users, via a data bus, in particular via a single-channel data bus, in particular a controller designed as a further bus user, wherein the first electrical device has a first logic unit and a first computer unit, the second electrical device has a second logic unit and a second computer unit, and a first circuit part of the first electrical device can be redundantly switched off, in particular switched off redundantly by the first logic unit and the second logic unit.