Runtime Configurable Tachograph Message Control
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Solution Overview
Problem
Existing digital tachographs require costly and time-consuming re-certification and reprogramming for software adjustments, limiting their ability to adapt to changing output data requirements.
Innovation Solution
A digital tachograph with a control circuit that allows configuration of message types and transmission behavior at runtime via a configuration interface, enabling user-defined message types without altering the programming or certification of the tachograph.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmission behavior is permanently programmed in the control circuit, then the tachograph operates reliably with certified software, but any change requires reprogramming and recertification which is time-consuming and costly
Solution Approach 1:
The control circuit is designed to dynamically load message type definitions from external storage media at runtime rather than having them permanently programmed. This allows the system to adapt its message transmission behavior flexibly without requiring reprogramming or recertification, as the core certification remains unchanged while configurable parameters can be modified by loading different definition sets.
Solution Approach 2:
An intermediary layer is introduced between the certified control circuit and the message transmission functionality. This intermediary allows configuration data to be loaded from external sources and interpreted by the control circuit without modifying the certified software code, thus maintaining reliability while enabling adaptability.
2Adaptability or versatility
If reprogramming is performed to add new message types, then the tachograph can meet new customer requirements, but recertification is required which increases costs and time expenditure
Solution Approach 1:
Message type definitions are prepared and stored on external storage media in advance. When new customer requirements arise, pre-prepared configuration data can be loaded without requiring time-consuming reprogramming and recertification processes, significantly reducing the time loss associated with certification.
Solution Approach 2:
Instead of changing the programmed code structure, the system changes operational parameters by loading different message type definition sets from external storage. This allows customization for different customers while maintaining the same certified software foundation, avoiding recertification time.
3Ease of manufacture
If the tachograph uses fixed message type definitions, then certification is simplified, but the system cannot easily adapt to changing output data requirements
Solution Approach 1:
The message type definitions are segmented into separate configurable parameters that can be loaded from external storage rather than being monolithically programmed. This segmentation allows the certification process to focus on the stable control circuit while the configurable message definitions can be easily adjusted to meet changing operational requirements.
Data Source
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AI summary
The invention relates to a tachograph (11) for a motor vehicle (10), wherein a control circuit (16) is provided in the tachograph (11) which is configured to repeatedly record a respective current value (17) for a plurality of measured quantities during a journey of the motor vehicle (10) and to send messages (14) of at least one message type (14') via a communication connection (12).It is provided that in the control circuit (16) message types (14') are configurable at runtime of the tachograph (11) and for this purpose the control circuit (16) is set up to receive configuration data (20) for at least one user-defined message type (14') via a configuration interface (19) and to compile and transmit the messages (14) of the user-defined message type (14') according to the configuration data (20) at at least one transmission time (33) specified by the user-defined message type (14') and, during compilation, to determine the current value (17) of each measured quantity selected by the message type (14') and to convert it into a format specified by the message type (14').