Fieldbus Safety Control with Decentralized Actuator Logic
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Solution Overview
Problem
Existing safety-related control systems for hazardous plant components are inflexible, require extensive wiring, and are complex to configure and maintain, necessitating high bandwidth communication and central control that is prone to errors.
Innovation Solution
A decentralized safety-related control system using a fieldbus to directly connect safety sensors and actuators, allowing for simple configuration and execution of safety responses via a programming device that assigns safety responses to individual lines, eliminating the need for central control and reducing bandwidth requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hard-wired safety relays are used to link safety sensors and actuators, then safety functions can be executed, but the system requires extensive wiring and is very inflexible
Solution Approach 1:
The patent replaces the mechanical hard-wired safety relay system with a fieldbus-based communication system. Safety sensors and actuators are linked via digital communication protocols instead of physical wiring, eliminating the need for extensive cable connections while maintaining safety function execution. The fieldbus network enables data transmission between safety components without direct electrical connections.
Solution Approach 2:
The fieldbus system serves multiple functions simultaneously: it transmits safety-critical signals, enables configuration of safety responses, supports system diagnostics, and allows flexible reconfiguration without physical rewiring. A single fieldbus infrastructure replaces multiple dedicated safety wiring harnesses, providing universal communication capability across different safety components.
2Device complexity
If dedicated safety controllers are used to control safety actuators via fieldbus, then wiring is reduced, but complex programming and validation of logical operations is required
Solution Approach 1:
The patent extracts the complex programming and logical operation validation from the safety controller and relocates it to the safety actuator units. Each actuator unit contains embedded safety logic that automatically executes predefined safety responses when triggered, eliminating the need for centralized complex programming and reducing configuration complexity at the controller level.
Solution Approach 2:
Safety actuator units are designed to autonomously execute safety responses based on received trigger signals. The actuator units contain built-in safety logic and automatically perform the appropriate safety action without requiring external programming or complex validation, enabling self-service operation and simplifying overall system configuration.
3Reliability
If centralized control is used to execute safety responses, then coordination is achieved, but the system is prone to errors and requires high bandwidth communication
Solution Approach 1:
The patent segments the centralized safety control function into distributed safety logic embedded in individual actuator units. Each actuator unit independently contains and executes its own safety response logic, eliminating the need for high-bandwidth communication for real-time coordination. This segmentation reduces communication bandwidth requirements while maintaining coordination through the fieldbus network's ability to transmit trigger signals.
Data Source
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AI summary
A safety-related control system comprises at least one safety sensor unit and at least one safety actuator unit, connected via a fieldbus, and a programming unit. The at least one safety sensor unit provides sensor connections for connecting safety sensors to the fieldbus, with these sensor connections being assigned to safety lines. The programming unit displays the available safety lines to a user via an output interface and receives user input via an input interface. The user input assigns a selected safety response, executable by the safety actuator unit, to at least one selected safety line. The programming unit also stores the assignment between the selected safety line and the selected safety response in the safety actuator unit as a safety configuration.The safety lines assigned to the individual sensor connections can be activated independently by the at least one safety sensor unit by sending line activation signals from the individual safety lines. The safety actuator unit receives the line activation signals directly from the at least one safety sensor unit via the fieldbus and, upon receiving a line activation signal from an activated safety line, independently executes the safety response defined for that activated safety line in the safety configuration.