Whither Wireless? Which one? We talk about wireless as if it were some monolithic thing. It’s not.
There was a lot of wireless stuff at Hanover, even a wireless pavilion with many displays. My observation is that wireless means many different things. I see four broad categories:
- device-level
- fieldbus-level
- Ethernet
- RTU-level
The first one has some hype and/or controversy surrounding it. Wireless PROFIBUS has been around for quite a while, but not as part of the standard. Wireless Ethernet is available based on IEEE standards. Wireless connectivity to RTUs has been around for centuries (ok, not quite that long, but a long time).
I attended the Industrial Communication Trends panel in the Interkama section of the Fair on Wednesday. ARC’s David Humphrey moderated a panel that included Marc Van Pelt of the Fieldbus Foundation, Mike Bryant of the PTO, Ron Helson of HART Communications Foundation, and Harry Forbes of ARC. The focus was very much on wireless. Harry Forbes projected that 60-80% of process devices would use wireless soon. He admitted that these numbers were not based on analysis and were intended to spark discussion. Although there is wireless specification activity in the PROFIBUS and HART communities, the panelists did not think there would be a rush to wireless. Mike Bryant added that wired fieldbuses don’t even have much penetration against conventional, direct-wired systems. Perhaps 10-15% of systems use a fieldbus.
I spoke with Harry Forbes after the panel to inquire about security of wireless networks. He responded that for the device-level networks, the limited range was a deterrent to hacking. I asked about denial of service attacks (jamming the radio frequency). Again, Harry felt the limited range was some help, but there is really no defense against it. Later, in reflecting on these topics with Mike Bryant he and I realized that the effort to deliberately jam was probably high and that the risk from accidental jamming was almost nonexistent.
I came away with the feeling that a lot of the wireless talk was hype, even though Harry insisted users are demanding wireless devices. Like all else in industry, the users will vote with their wallets and only then will we know whether it’s hype or necessity.
At the fieldbus level, I don’t think any standards are in place for any of the non-Ethernet fieldbuses. PROFIBUS uses wireless, but each vendor does it his own way. Fieldbus Foundation indicated that they are not big fans of wireless. DeviceNet has no wireless capability that I’m aware of.
For the Ethernet-based buses the IEEE standards apply. One of the benefits of Industrial Ethernet is that it rides the rising tide of R&D from the office networking giants and the IEEE standards. This translates to advances in speeds, security, etc. without separate investment begin required from the industrial automation industry.
The radio connection to RTUs has been around a long time and I guess it’s outside the scope of the current wireless discussion.