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NeSSI Keeps Chipping Away

Feb. 16, 2010
The Plucky Sampling Sensor Initiative and Its Advocates Keep On Encouraging Users to Gain the Many Benefits That Its Standardized Hardware, Communications and Microanalytic Specifications Can Bring to Process Analytical Systems

By Jim Montague, Executive Editor

Some projects take longer than expected, and some take a lot longer than expected. But, pushing for any worthwhile change usually requires years of patience, thankless persistence and slow chipping away. Until one day, the general populace wakes up, and another 20-year overnight success is born that, of course, was obvious all along.

This is a common tale and the experience of the 10-year-old New Sampling/Sensor Initiative (NeSSI) for process analytical systems and its supporters is another good example. Launched in 2000 by the Center for Process Analytical Chemistry (www.CPAC.Washington.edu) at the University of Washington, Seattle, NeSSI's Generation I specification for its modular, compact, mechanical substrate and other hardware evolved from the ISA SP 76 standard. Next, CPAC and NeSSI's supporters released its Generation II specification for automation and communications in 2004 and more recently, its Generation III specification for microanalytical devices, which is NeSSI's ultimate goal (Figure 1).   

Communication Conflict

Since its debut, Generation I hardware has been produced by three main suppliers: Parker Hannifin (www.parker.com), Swagelok (www.swagelok.com) and Circor Instrumentation Technologies (www.circortrech.com). It's used in some process analytical systems and continues to gain traction. Unfortunately, NeSSI's wider adoption has been held back by a long evaluation and debate over Generation II's communication methods and the hesitation of some potential users to deploy it. Also, Generation III has been forced to remain in specification form and in the research lab until Generation II's communication issues are resolved.  

Figure 1. The eventual goal of the New Sampling/Sensor Initiative is to enable implementation of microanalytical devices in process analytical sampling systems.

"A year ago, we thought we were all set with Generation II's communications, but we're still working on pulling together the different ABB and Siemens approaches after several years," says Dr. Melvin Koch, CPAC's executive director. "This is a lot like the early days of the fieldbuses, when every supplier brought its own version. So,I guess we may just need a USB-type solution to come along."

In fact, Patrick Lowery, Circor's technology director, adds that NeSSI's steering committee has chosen Instrincally Safe (IS) CANbus as NeSSI's open communication bus, which ABB supports, but the committee is also allowing users to select proprietary i2C, which Siemens Industry supports. He also reports that Generation II's communication bus was certified by the CSA and approved by IEC last summer, and that two major installations already are underway, though so far they've declined to be identified.

"We were told by users that they want NeSSI, but when it comes to implementation there are risk-assessment issues, and they've been hesitant," explains Lowery. "The bright side is that, since launching Genration II's digital devices, we're seeing doors opening to a wider variety of customers, who may not want Generation I, but do want Generation II's IS CANbus for low-cost communication in difficult areas, such as high temperature, corrosive and small spaces. The other fieldbuses are a lot bigger and more costly, so we're trying to make IS CANbus as easy for users as USB. For example, a Foundation fieldbus node can cost $150, but a CANbus node can cost about $8."  

Standardization = Savings

Tracy Dye, engineering director for ABB's (www.abb.us.com) responsible product unit and a member of NeSSI's steering committee, reports that his company integrates NeSSI-based sample preparation loops into its analyzers, which it then delivers to its end users. "Generation I is crossing the gap from early adopters to early-mainstream acceptance, and this is because users are increasingly seeing the added value of standard NeSSI systems compared to traditonal sampling systems. However, we still need to constantly reiterate NeSSI's value proposition, which is that it can take much of the custom engineerring out of sampling systems and replace it with standard engineering to reduce time and money."

As for Generation II's communication bus, Dye reports that NeSSI's steering team continually discusses progress on each communication bus, but the issue isn't settled yet because of these different directions. "Still, we're optimistic, and we don't see any turning back on the gains that NeSSi has made so far," says Dye. "The value of Generation I's hardware is proven, and Generation II's communications can enable remote visibility into sample handling systems where there used to be none, and gain efficiencies, too."

For instance, instead of just doing scheduled maintenance, data from a Generation II sampling system can enable maintenance-on-demand efforts by letting users know immediately when a filter is getting clogged. "The traditional way is that a clogged filter starts to impede flow to the analyzer, which starts to produce invalid data, and so data calculations to the DCS become invalid," adds Dye. "The usual delay in fixing this kind of problem can be hours, days or even weeks The real value of Generation II is that it can indicate a problem and show its location right away,  so users can solve it immediately. This means a lot of potential savings by not having otherwise invalid data, and also means more uptime as well."

Some Recent Gains

Despite the hurdles and delay of recent years, NeSSI's organizers remain mostly undaunted and point to several recent gains as indications that NeSSI will eventually achieve the widespread adoption it deserves. "NeSSI is starting to reach into prime time," says Steve Doe., analytical market manager in Parker Hannifin's instrumentation products division. "In fact, we're entertaining and wiring four or five project-scope orders right now."

For example, though it was recently scaled down and back a bit, an ongoing NeSSI installation at ExxonMobil's Singapore Parallel Train (SPT) project on Jurong Island, Singapore, is still expected to be one of the biggest NeSSI installations ever. The project was reportedly going to have more units and use Generation II's communications, but the user reportedly decided to just use Generation I's hardware for now. As a result, SPT is presently implementing about two dozen container/shelter units, and each of these has six to 12 sampling systems. The sampling systems are located on the outside of the containers, while the analyzers are housed on the inside. In these kinds of applications, NeSSI usually performs stream switching, final filtration, atmospheric referencing of gas chromatographs and other functions. 

Besides convincing users to adopt NeSSI-based sampling, Doe adds that suppliers must also train their technicians to use it. "At first, some people object to NeSSI with statements like, 'Where's the flow?' and 'I can't follow the tubing.' As a result, we show them NeSSI's documentation, let them take apart and reassemble our IntraFlow modular fluid handling components, and show them how to troubleshoot it. Training is crucial because if technicians don't get NeSSI training, they'll get that deer-in-the-headlights look, and they won't use it and be able to gain all its benefits," explains Doe. "So, we need to be proactive, get feet on the ground to do training and probably throw in a BBQ as well."  

Jim Montague is Control's executive editor.

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