In order to provide information for the diagnostics and maintenance of systems, we develop and test IoT-based measurement acquisition systems and platforms together with industrial partners. Through the further development and application of innovative wireless sensors and clamp-on measurement technology, we can retrofit buildings and systems in a minimally invasive and cost-effective manner. In case of a difficult integration of data from existing automation systems, plants can be characterized with this metrological alternative. The measurement data can then be analyzed, for example, on an embedded system using diagnostic and forecasting procedures, and results can be provided in the event of an anomaly to building operators.