CODESYS: The virtual safety controller

In a two-part series of articles, we shed light on the path of the PLC towards virtual control. In this second part of the article series, the focus is on functionally safe controllers - i.e. safety controllers. Can they also be virtualized?

The abstraction of machine controllers makes sense: the consistent further development of control technology towards virtual controllers considerably reduces the effort required for acquisition, commissioning, expansion, maintenance and decommissioning. With virtual controllers based on container or hypervisor technologies, only the software determines the function - the hardware provides the abstracted substructure for it. Because dependency on specific devices has been overcome, modern control architectures with security-by-design and dynamic microservices can be easily realized. But what about functionally secure applications?
EU regulations and national laws stipulate for the protection of people: Machines with a hazard potential of any kind must be safeguarded for the entire life cycle - either through design measures or safe control technology in accordance with the state of the art. IEC 61508 defines this status with basic terms, design principles and general aspects for the use of electronic controls in machines and systems. Thus, among other things, the safety requirement levels SIL (Safety Integrity Level) 1 to 4 are described, based on the hazard situation in terms of severity and exposure frequency, for example. Due to the legal situation, a machine or system must be approved by an accredited institute before it is put into operation - including all components used to achieve the requirement level as well as the implemented control application.

Read the full article on » or in the Computer&Automation, issue 08-2023, p.40-44 »

This article is only available in German language.

Author: Roland Wagner, Head of Product Marketing, CODESYS GmbH