PARTICULAR CHARACTERISTICS OF TODAY’S MICROELECTRONICS AND MATTERS OF HIGHLY DEPENDABLE AND SECURE CONTROL SYSTEMS DESIGN

Abstract

Aim. Drawing the readers’ attention to the growing number of industrial disasters, associated damage, increasing human casualties and the connection of this phenomenon with computer-based automation systems. The authors produce arguments regarding the requirement for design technology with extended security features in view of the multifold growth of abnormal natural and industrial effects. The paper describes and analyzes distinctive features of control systems of critical application facilities and consequences of disregarding additional inspection of circuitry and software. Of special note is the growing risk caused by the introduction of unmanned technologies and their mass application in railway and automotive transportation. The paper examines the problems of control systems resilience to faults and external actions depending on the used components. Statistics of industrial disasters are provided, their connection with the indicators of control systems instability is examined. A special emphasis is put on the distinctive features of today’s microelectronic components and the effects of technological progress on the systems’ interference immunity and fault rate. Of note is the growing number of hazardous failures in systems based on 0.13-μm and lower microcontrollers. A significant attention is given to the research of the distinctive features of modern chips, their layout, particularly of the main element of a control system, i.e. the microcontroller and digital signal processor, the influence of the external effects on the chip. The matters related to CMOS layout in microprocessor-based units are considered, the dependance is shown between the rising noise influence and migration to new CMOS technology. Attention is drawn to the requirement to train an appropriate class of specialists able to work with such systems who have not only software engineering skills, but also profound knowledge of physics, fundamentals of control systems design and their stability. Results. A comparative evaluation of stability of 0.5 μm and 130 nm CMOS stability has been conducted. The resultant difference in threshold power of interference is over 4000 times. It is noted that most developers who design software for such systems are mislead by the non-availability of any public information on the fault rate of processing elements from the manufacturing companies. By taking the dependability figures as the main parameter they misjudge the safety integrity level, as instead of the fault rate parameters they erroneously use the microchip’s dependability figures provided by the manufacturer. Additionally, standard methods of improving the safety level used by developers (e.g. redundancy) often prove to be inefficient. Conclusions. Designing highly dependable and safe control systems must take into consideration the distinctive features of today’s computer components given the fact that new generations of modern microchips due to their fault rate characteristics are often unusable in highly dependable system design. It appears to be of relevance improving existing standards and developing new ways of increasing the stability and safety of systems. Also noted is the requirement of maintaining the level of education and awareness of a wide community of developers who work with control systems in transportation, energy, industrial automation, weapon systems, etc. as regards the importance of ensuring the required level of functional safety.