Process Control via Network

The explosive growth in the area of computing and networking has occurred. This has caused an increased reliance on distributed computing and process operations across the networks. The main aspect in the process control across network is the network delay, which depends on the network type and protocol. This paper gives the literature review about the network-based control systems and the methods developed for handling and compensating the network delay in a control loop. In the experimental part the research environment for examining the control performance of a laboratory-scaled process across three different wired networks and wireless ad-hoc network is described and the control results are compared. The wired networks are Ethernet, Internet and FUNET, which is the network operating between the universities in Finland. This means that the distances between the operator and the process to be controlled vary remarkably from twenty meters to several hundred kilometers. Also the transmission speed of the network is different. The network delays are measured and compared with each other. Also the loss of data packages in different networks is examined.