WAP and SMS based emerging techniques for remote monitoring and control of a process plant

Remote monitoring and control of data (usually large in number) present in a plant is conventionally done using structured cables (large number of wires) running between the field devices and the control room. The control room makes use of custom made programs to perform the necessary man-machine-interface (MMI). Now-a-days, new devices appear (mobile phones supporting WAP protocols, PDA's etc.) offering the possibility to be instantly and more efficiently informed, the instantaneous changes occurring in the critical parameters of the plant. This paper presents how cellular telephony technologies like the short message service (SMS) and the wireless application protocol (WAP) may be implemented effectively to assist the control and monitoring of a process plant. The techniques that can be used to provide visualization and control signals along with messages and alarms from the plant is explored in this paper. This is particularly useful in large and distributed processes such as chemical, oil industry etc. The objective is to equip the plant decision makers with all the possible plant information as quickly as possible in pocket-sized devices and also eliminate the need for wires. The work enables the technical and maintenance personnel supervision and control of machinery and processes from a single mobile phone. The proposed work has been implemented in a real time process plant (used in the manufacture of additives) consisting of heat exchanger elements, drums, reactors etc. On-line data are successfully transferred to the mobile device of the expert people at regular time intervals. An alarm management program is written using WAP protocol to provide an alert signal as and when any received data exceeds a set threshold value. The operational range of the plant is expected to improve significantly with these new emerging data transfer techniques. In this paper, the WAP content is provided with a graphic screen along with the usual text display. Graphical displays are incorporated in the form of trend graphs for the selected process variables in the mobile device itself. The paper also presents a scheme for secure transfer of data by using crypto coding schemes. Each information packet is coded to consist of the plant-id, parameter-id, user-id along with the actual data. Varying access rights are incorporated to define different data to be viewed.