In traditional mechanical and plant engineering, commissioning is one of the critical process steps. After all, potential weaknesses in the control software can only be identified at this late stage. These may result in costly reprogramming or even the mechanical conversion of the system. By testing the commissioning in advance on a digital twin and optimizing it in the digital world first, nasty surprises of this kind are now a thing of the past. What's more, if the digital twin of the virtual system is made up of individual assemblies, the designer can try out different variants cost-effectively and thus adapt the system to the customer's specific individual requirements.

If you also use existing digital twins of the assemblies used in the system on an open platform in the form of a modular system, the effort is reduced even further. As the control system on the virtual system can be created in parallel to the construction of the real system, there are also no waiting times in terms of system availability. The entire development process can therefore be shortened compared to the conventional approach, despite customizing the system.

Software development is increasingly becoming part of the commissioning phase.

Customers are increasingly demanding machines and systems that are customized to their needs. This means that every machine or system is unique. Software development is increasingly becoming part of the commissioning phase, as the growing complexity of the systems can only be mastered by programming the functionalities on the real system. In production, around two thirds of the control software (PLC program) is used for error detection and primary error response. Until now, it has only been possible to test this part when the system is put into operation, because only here can the specific error patterns be provoked. To make matters worse, certain error situations cannot be created in reality, for example because of the associated risks to people and the environment or to avoid damaging or even destroying the system.

This challenge is optimally solved with virtual commissioning. The system is available digitally at an early stage in the engineering process. Software development can start during the construction phase at the latest, ideally during the planning of the system. This means that the software is usually available at an earlier stage compared to the classic approach. This shortens the development time and allows for optimizations (processes, mechanics, sensor positions) in the system design - an aspect that represents a huge advantage, especially in view of the often tight schedules and project delays.

The system tests can be carried out with real fieldbuses and in real time. As it is possible to continually adapt and test both the control software and the system in the virtual space and then "turn a wheel" again, the result is improved software quality as well as increased system performance. For example, a sensor can be moved or a missing one added within seconds. And because every malfunction or error scenario can be simulated virtually and reproducibly with cycle accuracy, system safety and therefore quality are also increased.

Critical situations can be simulated on the computer that it is better not to cause or even bring about in reality, even for training purposes, as the system has to produce. With training in the virtual world, however, the operators can prepare themselves well so that they can react correctly if the worst comes to the worst and restart production as quickly as possible. Training on the computer also increases the productivity of the system - after all, the system operators can get started immediately after commissioning the machine without first having to complete an "operator crash course" and blocking the system in the process.

In the virtual room, it is possible to adapt the control software or the system further and further, test it and then "turn a wheel" again.

There are even more advantages if the system is built on a modular basis. Experience shows that even in special plant construction, 80 to 90 percent of a plant is built from standard assemblies. During commissioning of the system, the new combination of assemblies tailored to the customer must be tested. Added to this is customer-specific technology in the sense of new developments.

These assemblies include kinematic units, tool and workpiece handling and the tools themselves, each with their own specific features. If several designers, even from different disciplines, are entrusted with the development, they can work on the various assemblies in parallel. As soon as all assemblies have been fully described, i.e. mechanically, electrically and in terms of software, the entire system can be configured. The resulting modular structure of the system, consisting of separately tested and approved assemblies, also helps to optimize procurement.

It is even quicker if the virtual assemblies already exist. The virtual system is then configured from parameterizable assemblies. This process can even be completely automated using a configuration specification (parts list). The platforms required for the provision of digital twins, which are shared by machine and plant manufacturers as well as component and assembly suppliers, already exist at ISG: the TwinStore contains libraries of various virtual assemblies, for example for robot systems, drive technology, conveyor technology, gripper systems and sensor technology. These will be successively expanded.