As Andres Suazo discussed in an article last month (Pumps & Systems, May 2015), today's industrial engineers have many ways to monitor and control remote pumps, including wired Ethernet, wireless cellular systems and proprietary wireless systems. This follow-up article takes a closer look at proprietary wireless systems. It will highlight how one public water utility in Germany used a wireless system to monitor tank levels and eliminate costly cabling. Wireless technology continues to evolve. Many manufacturers offer license-free proprietary wireless radios. This technology has been widely accepted, thanks to its reliable performance. Typical applications include wireless I/O (replacing wired connections between field devices and control systems) or data radios (replacing wired serial connections between intelligent devices).
License-Free Proprietary Wireless Technology
In 1985, the Federal Communications Commission (FCC) made several frequency bands available without a license under certain conditions. These industrial, scientific and medical (ISM) license-free frequencies would eventually be adopted by industrial radio manufacturers and find their way into industrial applications. Proprietary wireless modules use ISM bands. The frequencies in the U.S. are as follows:- 900 MHz (902 to 928 MHz)
- 2.4 GHz (2.4 to 2.484 GHz)
- 5 GHz (5.18 to 5.825 GHz, but not continuous)