Regarding John Rezabek's September "On the Bus" column,: John, thanks for sharing your direct experience and for trying to march down the wireless road as far as it would take you. When the ISA100 standards committee was formulating its requirements, we used exactly the same set of specifications that were used to develop the ISA S50.02 standard that became Foundation fieldbus H1 and later HSE.
In short, we were attempting to make sure that the ISA100 network would be suitable to become the network for a "wireless Foundation fieldbus" when the technology was ready. If the field instruments must be battery-powered, then the technology is not quite ready for high- sample-rate control, such as for flow or pressure loops, but it should be ready for temperature and most level control loops—except that no supplier has yet to offer a wireless Foundation fieldbus instrument.
If energy harvesting, as documented by the ISA100.18 subcommittee, is considered, then all process control loops are ready for wireless Foundation fieldbus using ISA100 Wireless (IEC 62734). ISA100 already supports direct, peer-to-peer, dual-path, mesh networking, very low power consumption, and a speed that's much higher than hardwired H1.
Now all we need is for users like you to talk to your instrumentation suppliers about building wireless Foundation fieldbus. Too bad the right components were not available for your last project.
Dick Caro, CAP
Co-Chair ISA100.8 Users Working Group
[email protected]
