Companies with individualized products, such as companies in the machinery and industrial plant construction sector, are in the tension area between the complete individualization of the product portfolio and the long-desired scale effects. Generally, it is attempted to meet different customer requirements by creating and offering customer-specific variants, which serve as an important distinguishing feature for improving the competitive position. This, however, drastically increases the variant diversity and the complexity of the product spectrum, which is associated with more efforts and increases the costs in almost all areas of the company. The customer-oriented development and maintenance of the individualized products and systems presents new challenges due to the constant change of internal and external conditions as well as customer requirements changes during the order processing process plant operation and re-engineering. This leads to a further increase in the complexity of the order processing and the development process, which, inter alia, necessitate an increase of the flexibility within the company. The lifespan of large plants is usually several decades. During operation, individual components and parts of the systems are constantly maintained, optimized and renewed. With such large systems it is difficult to keep track and ensure that all work done is documented and filed accordingly. Most of the systems were still developed and built without the use of digital technologies, and the documentation of such systems only exists in paper format. Accordingly, after a few years of operation, certain discrepancies exist between the real plant and the plant according to the documentation. Before further optimization and renewal, a re-stocking (usually only for a small part of the plant) must take place, which can be costly for urgent repairs and possible downtime. The ability to record and digitally and mechanically read the individual components could be a major step in accelerating maintenance processes and improving spare parts management. In the context of this work an approach to the inventory of a process plant is presented. The requirements for different process components are summarized and an approach for combining the components into a system model is developed. This would be the transition from obsolete document-centric system development to a model-based one. The component of the complete or partial model of the system can be used for other subsystems of current process plant or other systems.