Mr. Hess, after the soft PLCs now come the virtual controllers. Could you please briefly explain the differences between the two?
Dieter Hess: I'll start with the similarities: Both are based on the same technology, i.e. CODESYS. What is different: With virtual control, you have operation in a virtualized environment, which typically means in the virtual machine or container.
What are the advantages of virtual controllers?
Even greater hardware independence is achieved than with soft PLCs because the virtual controller includes part of the operating system. This avoids a whole range of compatibility issues.
avoided. Typically, with virtual controllers, not only one controller is operated per device, but many controllers are operated on one server, in one IT environment, i.e. server room instead of control cabinet. This has the advantage that these controllers can also be managed by the IT, which is generally present in such production plants. This results in uniform conditions in terms of backup or security, for example. Which of course comes into play when you operate many controllers on one server: The I/Os are not controlled via a single interface, but they are controlled by a network infrastructure, such as switches. This is a significant difference and also an advantage of virtual controllers.
Do you see the fact that you don't need a control cabinet as another advantage of virtual control systems?
Saving on the control cabinet is not the key issue. The advantage is rather that everything is stored centrally on a server. If you need to make an update, for example because of a security patch, you can make the new image available and shut down and restart all the controllers in the patch. This can be automated and is much faster than before with one hardware per controller.
Read more: You can download the full article from elektrotechnik Automatisierung magazine issue 03/2024 here.
This article is only available in German language.
Author: Angela Unger-Leinhos