The topic of my work is connected to one of the Prolan Zrt. developments; whose goal is the realisation of a railroad management equipment of high safety value. The equipment shall fulfil the highest, SIL4 safety requirements. The development is carried out in a project supported by EU. I outline the equipment and the problems to be solved through the “IP basis safety contact copier” system called ProSigma. My task is the writing of the software of one of ProSigma logic control unit.
In the first part of my work I give an overview on the safety, safety requirements and the standards applied in the course of the development life cycle. After that I present the requirements the system shall meet.
Having described those I go into detail concerning the entire system, focusing especially on the setup of ProSigma, and make a short summary on the protocols and the architecture ensuring the fundamental safety of the system. In the following chapters I indicate the construction and the function of the software and give information on how their planning and realisation was influenced by preliminary considerations. I list the software components, and describe the way these are linked. Besides this I write on the realisation of some fundamental functions, namely the event treatment and the persistent data storage. At the event treatment I deploy details on the type of events, and the suitable handling of these. I deal with persistent data storage in a separate chapter likewise.
The equipment provides an opportunity for distance diagnostics and distance supervision. While reviewing the functions I deal with the reading and writing of the single memory areas of the system.
After the general review of the software, I start with the description of the two most important software components, the basic program and the application program. In the first part of description I outline the requirements, in the second the realisation. The basic program I go into detail about the organization of the program, I outline the single software layers, the possible system states and the process of the communication with the environment. I illustrate the most important functions with the applied protocols. I go into detail regarding the actual application, the software realisation of the barrier performance in connection with the application program.
Finally I write a summary on the realisation of the system, and then outline the opportunities for future development.