The paper presents the realization of a control-loop performance monitoring system operating in a cloud as a single unity for the global supervision of data coming from various industrial plants located in different areas. This is a desirable solution for many companies, because of the costs of local installations (systems, human resources, and their maintenance and upgrading) and is made possible by available Industry 4.0 technologies, although some aspects are worthy of deeper investigation, depending on specific industrial realities. The monitoring system (PCU, Plant Check Up) is described in its basic components and its evolution toward the cloud-based configuration. The entire architecture, as well as the solutions adopted for data acquisition from the field, transmission to the cloud, and web app features, which allow a full remote monitoring, are illustrated. Technical details about the application on a pilot-scale plant are given, and results for significant cases and different types of loop and actuator status are presented.