The term “wireless” gets bandied about quite often these days among process manufacturers and automation suppliers. As process automation and IT professionals take an interest and look more closely, they begin to see different areas where wireless might be applied. Standards like WirelessHART for field device networks, asset management software and automation systems help provide interoperability.
Wireless plant networks, on the other hand, provide higher-level applications like mobile worker, safety mustering/personnel tracking, and plant video coverage to name a few applications.
I caught a sneak peek of an article written by Emerson’s Neil Peterson for Canadian Process Equipment and Control News. The soon-to-be-published article, Choosing a wireless network provider? Look to a standards-based solution., offers guidance for incorporating a wireless plant network.
A key recommendation is make sure the wireless technology is compliant to the 802.11 standards for communications, security and quality of service. Neil notes that these standards are driven by the IT community and not specific to the process manufacturing industry. Choosing a solution that is proprietary causes “vendor lock in” and change comes at a price. If the vendor you rely on is no longer in business, you may be stuck without a good path to standards-based wireless solutions. Also, with a standards-based solution, the infrastructure costs can be shared among the various wireless application projects and plant departments that use this infrastructure. Many applications not economically viable with a wired solution become viable with wireless technology.
When executing a wireless plant network, Neil advises to look for a single-source contractor to integrate the standards-based solution to be responsible and a single point of contact for issues when multiple vendor products are involved. This selection provides choices on wireless devices and suppliers and competition on quality, form factor, ease of use, etc.
Unlike self-organizing WirelessHART field device networks, wireless plant networks usually require a radio frequency (RF) site survey to understand the challenges and obstacles to reliable wireless communications. The survey is important in the network architecture design and planning process to assure the required quality of service for the intended application. Neil offers a video application example where both the video application and the wireless equipment must support the quality-of-service provisions covered under 802.11e in order for the video to share the wireless network properly.
Neil sums up his thoughts that a standards-based approach to your plant wireless network infrastructure helps you to take advantage of new applications conforming to the standard as they become commercially available. With a proprietary approach, you’re limited to what the supplier develops and when it gets developed.