A High Availability Networked Control System Architecture for Precision Agriculture

Precision agriculture systems are usually studied in the context of Wireless Sensor Networks. In this paper, a hierarchical Networked Control System (NCS) is proposed for two Greenhouses. This system is built on top of switched Ethernet and Wi-Fi, and is IoT-based. Fire and CO2 sensors imposed a 1s real-time deadline. It is shown how to allocate Wi-Fi channels to prevent interference in this relatively large NCS. Riverbed simulations proved that the two-Greenhouse NCS did not suffer any packet loss and was able to meet real-time constraints. Fault Tolerance at the controller level is then added to the system. Riverbed simulations again proved that the system can operate as a 1-out-of-2 system; if one controller fails, the other controller can operate both greenhouses. A case study is then presented to show that fault tolerance can decrease downtime which is a very important advantage especially in developing countries.