Modern instrumentation and building control technology is provided as web servers. The web servers run directly on the customer's control units, on PC systems, or server systems. Operation takes place conveniently from a web browser on the PC, tablet, or smart phone. On request, ERC MSR installs PC systems which can be used to execute and document all switching and control processes. The system is also used for the recording and display of measurements, as well as the operating data recording of consumption values, operating statuses, fault messages, etc. If necessary, the PC system can be equipped with interfaces in order to communicate with superordinate computers.