Networked Plantwide Process Control with Asynchronous Communication and Control

The need for economic efficiency and safety has driven the development of large and complex chemical plants. Due to the presence of interactions, controlling such plants are often difficult. This paper aims to address this issue by developing a networked-based process control approach. In this framework, a plantwide process is modeled as network of process units which is controlled by a network of autonomous controllers. The controllers within the network operate with different sampling rates and communicate with each other asynchronously, to allow flexibility and better utilization of communication bandwidth. A key feature of controller network is the connective stability among controllers, which ensures plantwide stability when communication problems such as data packet drop-outs occur. Using the concept of dissipativity, plantwide connective stability and global performance is translated into conditions for which each controller has to satisfy. The controllers are then designed individually to form an autonomous and distributed control system.