NeSSI Progresses From Vision to Reality

7. A temperature-controlled enclosure for sampling system and analyzers where standardized designs will help standardize an area classification inside the enclosure.

Formal specifications, development, and evaluation of NeSSI II-compliant devices is in progress. If all goes according to plan (Figure 3), NeSSI II-compliant components should be commercially available in summer 2005. Jacobs cant wait. "Im at a juncture where I need to do it now. Im working with two companies that are not only shrinking sensors to give us a smaller footprint, but are also giving us jumping-off points to do other things as well. For instance, one vendor is modifying a sampling system to make it look like a web site, so I can not only query from a remote location but, with the added I/O, input signals into the sampling system from other sensors as well as output signals to give me control over the valving and some of the things I want to do."

Jacobs also comments that because Ethernet is ubiquitous, not only does he have the ability to control various remote devices, the analyzer technicians in the field can also access manuals and other needed information from other computers on the network.

One element of the NeSSI vision of success allows a designer to design, build, and document a complete analytical system on the bench using very simple tools. "To do this, not only does the mechanical system have to be simple to assemble, but power/communication needs to be pluggable," says Rob Dubois, senior analyzer specialist at Dow Chemical Canada, Fort Saskatchewan, Alberta. "In electrically hazardous areas, this means using, where feasible, intrinsically safe (low-power) methods using simple wiring and connectors. Honeywell Labs and Honeywell Automation are in the process of building a proof of concept apparatus prototype that will demonstrate the use of simple sensors and actuators operating over an intrinsically safe multi-drop network."

The vision for third-generation NeSSI-compliant systems includes wireless connectivity as well as labs-on-chips and other microanalytical devices. In fact, "NeSSI has provided a very interesting reason and enabling tool for miniaturization of analytical instrumentation," observes CPACs Koch.

"The majority of the 20 research projects now underway at CPAC involve building instrumentation that will be NeSSI-compatible, part of the Generation III concept," he continues. "When some of these projects started at CPAC in the mid-1990s, critics in the oil and petrochemical industry thought we were wasting our time because they were accustomed to large sampling systems attached to large process analyzers. However, once a few of the NeSSI units were built and attached to an analyzer, even something as small as a process GC, the engineers started asking why the analyzer had to be so big. Now they are not only appreciative of miniaturization technology, but are encouraging its development."

"People have asked the question, Will NeSSI standardize analytical system design? The answer is, sort of," says Dubois. "Having standards such as SP76 certainly help, as will a sensor/actuator communication standard. However, most analytical systems have personalities to accommodate nuances in specific processes or measurements. Consequently NeSSI systems need to be flexible and highly configurable to work within the constraints of simple, but not inflexible, mechanical, electrical, and software standards."

Field Editor Mark D. Weiss is a Rockland County, N.Y.-based freelance writer and long-time contributor to CONTROL.