Abstract
The CLEARSY Safety Platform (CSSP) is both a hardware and software platform aimed at developing safety critical applications. A smart combination of hardware features (double processor) and formal method (B method and code generators) was used to produce a SIL4-ready platform where safety principles are built-in. A first version, SK0, was released for education purpose with a restricted application template. An industry-strength version, CS0, was then released, providing more degrees of freedom at the cost of a more tricky development and engineering process. This article presents the new CS0 modelling paradigm, lists the conditions to be verified by the system developed, and briefly introduces a first application, software only: a safety flasher.
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- 1.
The software model is proved to be defect-free - complying with its formal specification and without programming errors. The code generators and the compilers are not defect-free. They are not required to be defect-free as the defects are detected with divergent behaviour during execution.
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- 3.
The safety case contains all the details leading to complete demonstration (SIL4) but is not disclosed here (the safety case is around 120 pages). The CSSP has already been certified 3 times.
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The top-level sequencer is hard-coded and cannot be modified.
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In B, a BASIC machine is a component with a formal specification (a B machine) but with a handwritten implementation. A BASIC machine allows to integrate third party software in a B project.
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I/O requirements are so diverse among the safety systems we have been involved into that we have decided to separate I/O from the safety computer.
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They are not detailed here, but may be found in the CSSP \(CS_0\) User Manual.
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The complete safety flasher model and code are going to be available on [3].
- 9.
The situation is different from the SK\(_0\) where these function calls were included once for all in the top-level sequencer, not modifiable by the developer.
- 10.
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Acknowledgements
The work and results described in this article were partly funded by:
– BPI-France (Banque Publique d’Investissement) and Métropole Aix-Marseille as part of the project LCHIP (Low Cost High Integrity Platform) selected for the call AAP-21.
– ADEME (Agence de l’Environnement et de la Maitrise de l’Energie) selected for the programme “Vehicle of the Future” of Investissements d’Avenir.
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Lecomte, T., Lavaud, B., Sabatier, D., Burdy, L. (2020). A Safety Flasher Developed with the CLEARSY Safety Platform. In: ter Beek, M.H., Ničković, D. (eds) Formal Methods for Industrial Critical Systems. FMICS 2020. Lecture Notes in Computer Science(), vol 12327. Springer, Cham. https://doi.org/10.1007/978-3-030-58298-2_9
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DOI: https://doi.org/10.1007/978-3-030-58298-2_9
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