Communication Link Monitoring With Remaining Runtime Check
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Solution Overview
Problem
Existing communication protocols in safety-relevant systems fail to minimize the maximum reaction time in the event of an error, leading to inefficient response times and larger safety margins, which can be reduced by calculating a remaining runtime and checking if it is less than the cycle time to trigger a monitoring signal.
Innovation Solution
A method that calculates a remaining runtime from the difference between a monitoring time and a timer, checking if it is less than or equal to the cycle time, and generates a monitoring signal to switch from process values to substitute values when the remaining runtime is less than the cycle time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system waits for the watchdog time to expire before reacting to an error, then the monitoring is simple and reliable, but the maximum reaction time in case of error is increased
Solution Approach 1:
The system performs a preliminary check by comparing the remaining watchdog time with the cycle time before the actual error reaction occurs. This advance comparison enables the system to prepare for and execute the error response more quickly, reducing the maximum reaction time while maintaining reliable error detection.
Solution Approach 2:
The system dynamically adjusts its monitoring approach by continuously evaluating the relationship between remaining watchdog time and cycle time. This dynamic evaluation allows the system to optimize its response timing based on current operational conditions, thereby reducing the maximum reaction time without compromising reliability.
2Reliability
If larger safety margins are implemented to account for worst-case error scenarios, then system reliability is improved, but system scalability is reduced and safety distances must be larger
Solution Approach 1:
The invention changes the temporal parameters of error monitoring by introducing the remaining watchdog time comparison mechanism. This parameter change enables more precise timing control, allowing the system to maintain adequate safety margins while reducing the conservative overestimation that limits scalability.
Data Source
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AI summary
The invention relates to a method for monitoring a communication link between a first participant (1) and a second participant (2), wherein a first processing program (P1) with a first cycle time (ZT1) is executed cyclically in the first participant (1), a first diagnostic unit (D1) with a first timer (Z1) is operated in the first participant (1) to monitor the communication link such that the arrival of a first telegram (T1) from the second participant (2) starts the first timer (Z1), wherein within a predefinable first monitoring time (WD_T1), the arrival of a second telegram (T2) from the second participant (2) is monitored using the first timer (Z1), and wherein a remaining runtime (RLZ) is calculated in the first diagnostic unit (D1) from the difference between the first monitoring time (WD_T1) and the first timer (Z1) and is checked.a monitoring signal (TO) is generated if the remaining runtime (RLZ) is less than or equal to the first cycle time (ZT1).