Sensors, actuators, and wireless communication technologies have developed significantly. Consequently, closed-loop systems that can be monitored and controlled by devices in IoT environments, such as farms and factories, have emerged. Such systems are realized by means of cloud-level and edge-level implementations. Among them, with a model that generates real-time control decisions at the cloud level, it might be difficult to ensure the determinism of real-time control due to communication overheads. In addition, if the actuator is remotely controlled at the cloud level, it is difficult to secure control safety against external hacking or device malfunction. Herein, we propose a system architecture that can fulfil real-time performance and safety requirements with two commonly used devices, Field Edge Unit (FEU) and Current Sensing Tag (CST), in a closed-loop IoT environment. By using these devices, we designed a special architecture that can be commonly used in various closed-loop sensing and actuating applications. In this study, the proposed architecture is evaluated by applying it to a smart farm application.
Keywords: IoT environment; closed-loop; sensor-actuator network.