Safety Control Module for Standard Operator Panel Input
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Solution Overview
Problem
Existing systems for safety-relevant input in control systems require hardware modifications to standard operator panels, leading to significant additional efforts and complexities.
Innovation Solution
A method using standard operator panels for safety actions by transferring object code and masked object code through two different communication paths, each going through a non-safety control module, with reference code values stored on the safety control module for verification, allowing the use of standard operator panels for triggering safety actions without hardware changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If standard operator panels are used for safety-related input, then hardware complexity is reduced, but safety reliability cannot be ensured without additional hardware modifications
Solution Approach 1:
The patent introduces a safety control module as an intermediary that mediates between the standard operator panel and the control system. This module receives inputs through the non-safety control module, verifies them against pre-stored reference values, and only activates safety functions when verification succeeds. This intermediary layer enables safety functionality without requiring hardware modifications to the standard operator panel.
Solution Approach 2:
The patent creates a copy of the object code through masking to generate a masked object code. This copied and transformed code is then transmitted through the non-safety control module and verified against reference values. The copying mechanism allows the system to validate safety-critical inputs without requiring the original hardware to be safety-certified.
2Reliability
If hardware modifications are made to standard operator panels for safety actions, then safety reliability is improved, but device complexity and modification efforts increase
Solution Approach 1:
The safety control module serves multiple functions: it receives safety-relevant inputs through the standard operator panel, verifies them against reference values, and activates safety functions. This multi-functional approach eliminates the need for separate safety-specific hardware while maintaining safety reliability.
Solution Approach 2:
The patent replaces physical hardware modifications with a software-based verification mechanism. Instead of modifying the operator panel hardware to be safety-certified, the system uses software masking and verification of object codes to ensure safety reliability, substituting mechanical/hardware solutions with software-based ones.
3Ease of operation
If object code is transmitted through non-safety control module, then ease of operation is improved, but information integrity may be compromised
Solution Approach 1:
The system implements feedback by comparing the received object code and masked object code against pre-stored reference values in the safety control module. This feedback mechanism ensures that even though code passes through the non-safety control module, any corruption or tampering is detected through verification, maintaining information integrity.
Solution Approach 2:
The reference values are pre-stored in the safety control module before any input is received. This preliminary preparation enables immediate verification of incoming code without requiring complex real-time validation, ensuring information integrity while maintaining ease of operation through the standard interface.
Data Source
AI summary
A system and a method for safety relevant input to a control system, the control system including a PLC which includes a non-safety control module for controlling non-safety processes, and a safety control module for controlling functional safety of processes, the system further including an operator panel for user selection of safety-related object input, wherein the system includes two communication paths between the operator panel and the safety control module, that each of the communication paths uses a different communication protocol, that each communication path goes through the non-safety control module to and from the safety control module, that the first communication path transfers object code and the second communication path transfers masked object code.