A major focus in the design of programmable electronic systems, to which safety-critical or mission-critical functions are entrusted, is to minimize the possibility of introducing errors in the system that later, during use, will manifest as "systematic failure"; for example: specification errors, design errors, errors in the implementation, installation errors, and so on.
The standards relating to the functional safety, especially the IEC 61508 and industry standards derived from it, have introduced the concept of systematic safety integrity, or the integrity of the safety of safety-related systems, in relation to systematic failures. One of the main methods required by the standards to achieve the desired level of systematic safety integrity, is to adopt a well-defined system development life cycle and perform within it two fundamental processes: the process of verification and the validation process.
HINTSW - T & T Systems has acquired extensive experience in the execution of the V & V processes in various fields of application, for example: the railway sector (IEC 50126, IEC 50128), the process industry and oil (IEC 61511) machinery (CEI EN 62061), the control and command programmable electronics systems (IEC 61508 and IEC 60730-1), and so on. Thanks to this experience HINTSW - T & T Systems is able to plan optimally the verification process and is able to perform all activities included in this process, in accordance with provisions of the industry standards and in accordance with best engineering practices.
In critical applications for human safety, HINTSW - T & T System Development acts as V & V "independent third party" , to carry out the verification activities in accordance with the rules prescribed for the role of "verifier".
Furthermore, in the case where it is necessary to achieve a safety certification, HINTSW - T & T Systems, assuming the role of verifier, is a familiar interface and competent between the manufacturer and the certification entity, with the result of making the certification process easier and economically sustainable.
As mentioned in the overview page of the V & V services, the verification process is, in short, to answer the question:
|Are we realizing this project properly?
The standards relating to the functional safety, primarily the IEC 61508, have established that in order to answer fully to this question you need to make sure that everything that has been achieved (products, output) during a certain phase of the development life cycle complies to the input requirements of that phase. The verification activities concerns, both the phase products (documentation, implementations, parts and components manifactured, etc.), and the design and testing activities (correct and complete execution of scheduled jobs, correct and effective application of methodologies and techniques prescribed, etc.).
The verification activities performed by HINTSW - T & T Systems therefore concerns the all phases of the system development life cycle. At the beginning of each phase, as soon as the input information are fairly consolidated, a set of control lists (one for each activity or artifact that must be verified) is compiled; in those lists all the elements (items) to be controlled and all the checks to be performed are listed; the checklists are therefore the guidelines under which all the verification activities of each step is performed.
The checklists are kept constantly up to date during the development of the various phases of the life cycle, so you can incorporate any changes to input information; at the end of every single phase the planned checks are performed and checklists are compiled, reporting the outcome of each single control.
After the compilation of all control lists of a phase, the corresponding audit report is drawn up; in that report an evaluation of the results of the controls is expressed and any non-conformities are reported, indicating the recommended corrective actions.
The verification is performed using several methods including inspections, reviews, walkthroughs, and inspections at the desk; in more complex cases, when there are so many items to be controlled, data bases and special supporting software are used, in order to "computerize" the verification activities. This allows a considerable saving on time and, above all, allows for greater control on the activities and the products of the various phases and greater completeness of the investigation.
The Safety Case
Some standards (eg standards of the rail sector) require that at the end of the development lifecycle is drafted a safety dossier, (safety case), which contains the demonstration that the level of safety integrity required has been reached. In these cases, the safety case is one of the most important output of the safety life cycle and normally his writing is rather difficult.
HINTSW - T & T Systems, particularly in the case of certification, it is able to effectively draw up the safety case in accordance with the standard requirements and with industry practice.