Wireless technology as a work in progress
What’s holding back broader adoption of wireless technologies in the process industries? A panel of vendor and user experts discussed that and other topics at this month’s ISA Expo in Houston. It seems that although technical and attitudinal obstacles to this emerging technology remain, many are being systematically addressed and overcome. Panel members included Peter Fuhr, Wi-Fi Sensors Inc.; Patrick Schweitzer, Exxon Mobil and ISA 100 committee co-chair; Jose Gutierrez, Emerson; Herman Storey, retired from Shell; Dave Kaufman, Honeywell; and Ed Ladd, HART Foundation.
One obstacle suggested by panelists was a sense of risk related to communication failures ("Can you hear me now?"). Another thought was that the discussion has largely moved from technical and reliability issues to disagreements over system ownership, meaning that, from the perspective of plant managers, IT groups tend to latch onto wireless more than other plant level technologies, and then want to exercise control or at least have influence over deployments.
While security is still an important concern, the consensus among current and potential users was that technical solutions are possible and are already being implemented. There were questions about use of wireless technology with safety systems and specific safety devices, such as gas detectors. The panel recoiled somewhat at the thought of using wireless with ESD (emergency shut down) related I/O, but was willing to consider things like gas detectors.
During the discussion, Herman Storey made a critical point about safety equipment: You have to ask yourself how you would know if it stops working. If a device isn’t supposed to do anything until there is a problem, you have to be able to verify that it is actually functioning all the time, so it can do its job when there is an emergency.
Users also are concerned about multiple systems interfering with each other, since there is a limited amount of air space. The group did caution against unmanaged deployments of multiple systems in a plant environment, since these can cause problems if not well thought out. But carefully planned systems can support a huge amount of equipment if applied well, particularly given the efficiency of current wireless process instrumentation.
The most contentious area related to wireless standards. The group was roughly split between those favoring WirelessHART and those favoring ISA-100.11a for process field devices.
The response from the two vendors represented were unequivocal: Emerson says it will only use WirelessHART, and Honeywell says it will stay with 11.a. Less aligned individuals suggested that the market will prevail in time, and that other vendors may not be so doctrinaire. Within the ISA 100 committees, there is a group that is seeking to create a convergence of the two competitors. However, in the near term, companies will have to make choices—it will not be practical for an end user to try them all.
Patrick Schweitzer, for example, says that Exxon Mobil has already selected 11.a for field instrumentation even though it is has been ratified for only a month. It will be interesting to see how the influence of such a major user will steer ongoing developments. The ISA 100.11a Wireless Compliance Institute also has completed a fully operational wireless instrumentation network following the standard at the Arkema organic peroxide plant in Crosby, Texas. (see sidebar below).
ISA 100.11a wireless demonstration project
In what may be one of the fastest deployments of new technology, the ISA 100.11a Wireless Compliance Institute (WCI) has completed an installation of a fully operational wireless instrumentation network following the new standard at the Arkema organic peroxide plant in Crosby, TX.
This project is already operating, even though the standard was ratified less than a month ago. It involves a group of specific monitoring points in the plant that were either inadequately instrumented or where the company wants to expand coverage, including firewater and wastewater tank levels, cold storage temperature and door sensors, and a single wireless SO2 gas sensor installed alongside an existing wired sensor.
In many respects, the specific applications of the devices themselves are not as important as what the project demonstrates. The point that WCI is trying to prove is that ISA 100.11a can be a multi-vendor platform with full interoperability. The devices in this case are made by Honeywell, Yokogawa, and Gastronics, with the wireless infrastructure provided by Honeywell and Nivis. WCI members make the point that while these individual devices were essentially hand made, the communication stacks and testing tools were already complete before the final ratification, so the transmitters were tested and are fully compliant with the standard.
The wireless devices currently feed into a separate monitoring point, but Arkema expects to integrate them fully into its main control architecture, as well as add more devices as they become available.