Safety Switching Device Fault Detection via Segmented Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing safety systems for automated installations struggle to accurately and efficiently identify faults, particularly distinguishing between internal and external faults, and provide centralized monitoring and diagnosis in increasingly interconnected systems.
Innovation Solution
A safety switching device with a signal processing unit, including a testing device and memory, that performs a switching test with multiple temporally-separated intervals to generate a test pattern for fault identification, using read-back signals to match against stored error patterns, allowing for the unambiguous detection of faults and differentiation between internal and external issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regular self-testing is executed to verify functional capability, then reliability is improved, but the ability to accurately identify fault nature remains insufficient
Solution Approach 1:
The patent segments the fault detection process into multiple distinct test intervals (first test interval, second test interval, third test interval) with different switching element configurations. Each interval tests specific combinations of switching elements, allowing the system to generate a unique test pattern that identifies not only the presence but also the nature of faults, including differentiation between internal and external faults.
Solution Approach 2:
The patent implements preliminary self-testing actions before normal operation to establish a baseline of functional capability. The testing device executes predetermined test sequences that activate switching elements in specific patterns, allowing potential faults to be detected and categorized before they affect actual operational reliability.
2Productivity
If devices are interconnected in automated installations, then productivity is improved, but the complexity of fault identification increases
Solution Approach 1:
The patent incorporates a testing device that provides continuous feedback about the operational status of switching elements. The device monitors test patterns generated during self-testing and compares them against expected outcomes, automatically identifying faults and their locations. This feedback mechanism simplifies fault identification in interconnected automated systems by providing clear diagnostic information without requiring complex external analysis.
Solution Approach 2:
The safety switching device performs self-diagnosis through automatic self-testing, eliminating the need for external diagnostic equipment or manual inspection. The testing device within the system independently executes test sequences, analyzes results, and identifies faults, allowing interconnected automated installations to maintain productivity while simplifying fault identification through autonomous operation.
3Reliability
If multiple switching elements are used for two-pole connection, then reliability is improved, but the difficulty of detecting and measuring faults increases
Solution Approach 1:
The patent divides the testing process into distinct intervals, each targeting specific switching elements (first switching element, second switching element, third switching element). By segmenting the test coverage, the system systematically checks each component's contribution to the two-pole connection, making fault detection straightforward despite the complexity of multiple switching elements working together for fail-safe shutdown.
Solution Approach 2:
The patent implements comprehensive testing that exceeds minimal requirements by testing all possible combinations of switching elements across multiple intervals. This excessive action ensures that even complex fault conditions in the two-pole connection system are detected, as the test coverage is more extensive than what would be minimally required for basic functionality verification.
Data Source
AI summary
A safety switching device for the fail-safe disconnection of an external consumer has an internal consumer and switching elements for connecting in parallel the internal consumer with the external consumer. Read-back taps are arranged between the switching elements, a first and second pole of the external consumer, and the internal consumer. A signal processing unit includes a testing device and a memory, in which a first error pattern set is stored. The testing device is coupled to the read-back taps and executes a switching test having a minimum of three temporally-separated test intervals. In each test interval, the testing device receives a read-back signal from each read-back tap in order to generate a first test pattern. To identify a fault, the testing device matches the first test pattern with the first error pattern set.