A recent study by strategy-consulting firm Venture Development Corp (VDC), Natick, Mass., (vdc-corp.com) says a large percentage of RF/microwave wireless technology users in industry apply it to control applications or both control and monitor. The identified control applications are mostly in setup and maintenance.

Of all survey respondents, 16% use wireless technology for monitoring only, 8% use it for control only, and 76% use it for both.

Users identified data communication, controller programming, and controller maintenance as applications in which wireless products are most used or specified for use. Wireless use in machine, process setup, and troubleshooting is more common than operational real-time control.

Users have two concerns with real-time automated control — signal reception drop-outs or blockage, and RF interference. Even a slight delay or corruption of data communication could have costly results.

Wireless operational real-time control is commonly found in applications with slowly changing variables, such as temperature control, flow control, or in those with operator control, rather than in automated systems for high-speed machinery. These applications are easily monitored independently and corrective action undertaken before damage is done.

Slow processes require less bandwidth (400 MHz, 800 MHz, and 900 MHz bands). Higher speed applications require more bandwidth and higher microwave frequency band operation (2.4 GHz or 5 GHz). Moving to higher frequency bands makes signal drop outs and blockage worse.

Wireless usage reduces wiring costs for large distributed systems. There may be little savings in wiring costs for many discrete manufacturing operations involving high-speed machinery as operating in higher RF/Microwave frequency bands for adequate bandwidth increases costs. However, the study indicates the use of RF/Microwave wireless technology in operational real-time control will eventually extend into other applications in discrete and process manufacturing.