The transfer of data within a process plant has seen several evolutionary steps over the past half century. Measurement and Control Instruments have moved from mechanical and pneumatic technology to electronic analogue (via remote terminal units (RTU)). Each step has seen an improvement in reliability, accuracy and the type of information available. Today we see digital only fieldbus networks which can tightly integrate equipment into a central control system, where use is made of not only the process data but maintenance and asset conditions too. The next evolutionary phase would be to remove the wires. In the last decade, proprietary wireless technology has been selectively used in process plants where the advantage of low cost, simple wireless installation is seen as a benefit. Because these solutions were proprietary, they were unable to gain large scale acceptance in the market place. Thanks to the emergence of standards derived on the use of low power components, wireless technology is now growing in acceptance for use in process plants. Standardization allows users to choose devices from a wide range of vendors and also solves three main issues with wireless networks: 1. Security; 2. Reliability; 3. Simplicity.
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