The scope of this study covers events resulting from improper functioning of machine control systems. An accident model providing a basis for formulating a checklist for accident analysis has been developed. Data about 700 accidents were collected. An analysis has proved that in the group of accidents caused by improper functioning of machine control systems, serious accidents happened much more frequently as compared to the group of accidents with no relation to the control system. The reasons for the majority of incidents caused by improper performance of safety functions consist in the errors made by designers. In view of that, incorrect behaviour of a worker should be treated as a normal event instead of a deviation causing an accident.

This article presents an analysis of results of 1035 serious and 341 minor accidents recorded by Poland's National Labour Inspectorate (PIP) in 2005–2011, in view of their prevention by means of additional safety measures applied by machinery users. Since the analysis aimed at formulating principles for the application of technical safety measures, the analysed accidents should bear additional attributes: the type of machine operation, technical safety measures and the type of events causing injuries. The analysis proved that the executed tasks and injury-causing events were closely connected and there was a relation between casualty events and technical safety measures. In the case of tasks consisting of manual feeding and collecting materials, the injuries usually occur because of the rotating motion of tools or crushing due to a closing motion. Numerous accidents also happened in the course of supporting actions, like removing pollutants, correcting material position, cleaning, etc.

This paper describes preliminary results of a project aimed at adapting workplaces for workers with motion disability through computer simulation and virtual reality techniques. For this task, a computer generated human model with a visualization of maximal arm reach and preferred working space was developed. Custom-made software was used to create a virtual working space, to adjust the human model’s measurements and constraints to reflect a disabled person, and to analyze necessary modifications. An immersive virtual reality environment was used to assess a modified workplace and to add further modifications.

The first part of this paper discusses the research context, taking a closer look at the development of Industry 4.0 and the growing importance of the IIoT, which entails new cybersecurity challenges. The issue of cyber threats and the need to increase the level of protection in machine control systems, which are particularly vulnerable to attacks due to their connection to the network, is also presented. The Introduction concludes with a presentation of the article’s objective, which is to analyze the requirements of security levels (SLs) and the implementation of relevant international standards. The next section reviews the current research on cybersecurity in machine control systems. This section also points out the research gaps that the article aims to fill. The next section presents the risk assessment used to ensure safety during machine operations based on ISO 12100. The article describes safety functions implemented in machine control systems, including the SIL (safety integrity level) and PL (performance level) specifications. An important part of the article is the creation of a relationship between PL and SL, showing how the safety functions of systems are related to protection against cyber threats. The last part of the article gives a case study in the form of examples of machines and their control systems performing safety functions, which require various SLs depending on the PLs.

Machine guards are commonly used safety measures that reduce the risk of machine use by preventing access to danger zones. However, a significant problem is the defeating of guards and safety devices. Research conducted in several EU countries has shown that in every country, over a dozen percent of shields are constantly defeated. The article presents the methodology of selecting and designing logic circuits that provide interlocking and locking safety functions. This methodology includes measures to limit the motivation to defeating interlocking and locking devices on guards and technical solutions that prevent defeating.