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In Swageloks MPC system, devices, such as valves, mount on substrate modules containing specialized channel and flow components.
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From Handling to Control While many of its Generation I modular-sampling are serving well worldwide, NeSSIs Generation II is moving beyond physical fluid handling to integrating the modular systems into plant control hierarchies.Rob Dubois, another NeSSI member and senior analytical specialist at Dow Chemical, says many modular systems are used in ethylene-hydrocarbon and ethylene oxide production applications and on a continuous-emissions-monitoring system for NOX at his plant in Fort Saskatchewan, Alberta. "Technically, the NeSSI systems work well and many of the modular components that previously had been missing are now available or are coming to market, he says. However, implementation has been slower than hoped for due to higher costs when compared to conventional systems. Right now, were missing a single-block, combined flow transmitter/indicator, which would really simplify and ease construction. Analyzer systems may have become smart, but the sampling system remains archaic. Today, the industry uses a hodgepodge of analyzer I/O, PLCs, DCSs, databases and proprietary systems.Generation II systems reportedly will solve this problem with a sensor/actuator manager (SAM) operating system, which will act as the communication channel between DCSs and analytical systems. Higher up, NeSSI systems communicate to the DCS using OPC over TCP/IP Ethernet, while Foundation Fieldbus (FF) is preferred at the field level. The CPAC/NeSSI steering committee incorporated FF into NeSSIs Generation II draft specification in February 2005 because its modular systems need FFs intrinsically safe operating capabilities.This initiative will help the automation industry adapt the merging class of lab on a chip sensors to a miniature/modular smart manifold, says Mel Koch, CPACs ditector.Dubois adds that Dows systems are operated on a local level, but once the intrinsically safe NeSSI bus is commonplace and supporting sensors and actuators are available, users will see tighter integration of the sample systems. Some major analytical vendors are now embracing the NeSSI vision, and are adopting both the fluid handling components, as well as the NeSSI-bus/SAM. Actually we have two possible buses: a miniaturized version of FF, which is work in progress, as well as an upcoming version of controller area network bus (CANbus) being undertaken by NIST and IEEEs 1451.6 effort.
Acceptance, Applications Growing
All three companies report theyre making inroads into the process analytical market, and claim doubling sales each quarter. There is a consensus that NeSSI has arrived, says Dave Simko, Swageloks marketing resources manager. Companies using NeSSI systems have shown that the cost savings are real. Although component cost is higher, savings in design time and manufacture generate 30% net savings.Swageloks Modular Platform Components (MPC) system
(See Figure 1 above) consist of fluid-control components, including shut-off, needle, metering, toggle and check valves, and filters, which are mounted on a substrate layer of 1.5-in.-square modules containing specialized channel and flow components.
FIGURE 2: GO WITH THE FLOW PATH |
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