Safety critical systems & softwares


1- Safety critical systems and software development


> ClearSy is a major player recognized in the field of formal methods for the hardiness of its applications. It proposes solutions different from those of its competitors by applying formal methods to develop its safety critical systems.

>Project management of the control system of the platform doors installed on Line 13 of the Paris Metro demonstrates our ability to develop Safe Operating industrial systems. Likewise, ClearSy has become a major player in the development of top-of-the-market safety critical systems: SIL2, SIL3, and SIL4 according to the applicable rail standards.


ClearSy is innovative in the packaging of software in terms of guaranteeing both the conformity of the software product and specifications to the customer needs. This warranty is possible due to the use of modelling techniques that allow, starting from the initial documents and exchanges, the creation of specifications verified by a formal method and expressed in a natural language.

This phrase allows the designers to eliminate the ambiguity of the customer requirement analysis, too often considered as developments, and provide a result entirely in line with needs. These specifications then act as the base for development created through techniques adapted for the operational constraints of the software product.

ClearSy offers contractual support to its warranty by a commitment to handle at its expense software changes related to a problem in the development of the code and the changes in these specifications if the problem is linked to a logic fault or ambiguity in the specifications. The development of safety critical software undertaken by ClearSy meets the development criteria of SIL2, SIL3, and SIL4 software in terms of IEC 61508 standards and, in particular, standards EN50126, EN50128, and EN50129.



A few examples of critical safety softwares developed by Clearsy :
> Development of safety software for the Val de Roissy with the B method
> Coppilot : Platform door control system.

2 - Electronic systems


> ClearSy provides support to its customers in the entire management of the safety properties of an electronic system. This ongoing management occurs from the system specification till its operational implementation (installation, placement into service, operational maintenance,…) as well as certification by the certifying authorities (TÜV, Bureau Veritas, Certifer,..).

> This management of “turnkey” solutions allows a company to benefit from the internal process of the ClearSy concept. In effect, this internal ClearSy process allows a company to manage negative impact events occuring at a rate less than 10-9 times an hour (corresponding to the SIL4 level).

> Today, ClearSy’s expertise in the field of design of electronic safety systems is widely known and appreciated by the industrial sectors facing foreseeable threats classified as dangerous (risk of death to humans), extreme use environments (weather conditions, EMC, mechanical), and requiring the highest levels of reliability required for electronic equipment.

CLEARSY : A laboratory of excellence in safety electronics

In order to meet the highest standards of safety system design, ClearSy has created a laboratory of excellence in safety electronics, capable of handling, among others, the following specific needs:

> Intrinsic safety design
> Design assistance
> Safety testing
> Remanufacture
> Maintenance.

3 - Safety softwares

Evaluation of safety software

> Ever since it was founded, ClearSy has applied its skills and technical expertise in modeling and engineering tools.

ClearSy’s activity centers on the constraints of operational safety. ClearSy aims at a wide range of partners, from industry to contractors as well as certification agencies responsible for specifiying, confirming, proving, or certifying their systems and software.

At the same time, ClearSy’s activities also involve safety management (safety plan, safety file) as well as the required safety analysis for systems or the component software.

From the Atelier B tool which it develops and distributes, ClearSy has acquired a complete mastery of formal methods which today provide it with an expertise in the highest level of software safety as well as the confidence of large contractors such as Alstom, Peugeot, DGA, Cybernetix, CEA, etc.
In the framework of the high safety levels required by the 61508, 50128, and DO178 standards, the use of formal methods is highly recommended.

Development of safety software

> Because of the use of modeling techniques, ClearSy is innovative in the development of software packages.

To accomplish this, ClearSy bases its approach on the entire set of documents provided by the customer, expressed in natural language and including the specifications related to the software product. Formal methods allow the Company to model the latter while guaranteeing its conformity while also adapting it as much as possible to the constraints of the contractor.

Developing safety software involves ensuring its proper operation and the impossibility for the software to execute dangerous actions. It also implies a thorough and rigorous mastery of the software operation.

Therefore, ClearSy uses its knowledge to meet the highest requirements of safety software through safety instructions developed in a structured, clear, unequivocal, verifiable, testable, and maintainable manner, completely unambiguous as far as the documentation is concerned and at all stages of the development cycle.

Our safety softwares projets

Here is a preview of a few projects requiring our safety systems know-how.
– Use the links below:

> Safety study of onboard softwares