Ask the Manufacturing Execution Systems (MES) Expert: Scheduling Assistance
 Asked on May 9 2006 5:46:18:000PM | Q | What's the story on wireless networks for process control? Frank, Burlingame, CA |
| A | The cost of wiring in most process plants is so high, and so expensive to maintain, that many users are just can't wait to use wireless. Several suppliers currently offer a proprietary wireless form of their field transmitters for common process variables such as pressure, temperature, flow, and level. I say "proprietary" because there is no standard of any form approved for industrial wireless communications. The closest to a standard is ZigBee that uses the IEEE 802.15.4 standard at the physical and data link layers, but their own Network and Application layers. ISA standards committee 100 is chartered with the development of the industrial wireless standard, and is still a long way from any standards. Without standards and an organization to validate conformance, interoperability between wireless instruments and control systems is only possible when all equipment is purchased from a single supplier. The work on S100 is good, but I don't expect a standard for at least two more years, and I am not sure what kind of a standard it will be. Wireless technology is still in a wild state of innovation, and it is really too soon to standardize on the physical or data link layers. |
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