Interface process monitoring

Figure A2.1 Waters ProMonix On-Line HPLC analyzer. The upper compartment door contains a keypad for programming and operation of the analyzer. The upper window allows viewing of indicator lights and a liquid crystal display that provides the operator with analyzer interface, programmed parameters, and instrument status results. The lower chamber contains the pumps, valves, injector, and detector(s) required for the chromatographic separation. The sample conditioning plate for online process monitoring is to the right of the analyzer. This is a typical process HPLC. (From Cotter, R.L. and Li, J.B., Lab Rob Autom., 1, 251,1989. With permission of VCH Publishers.)...

Identify each major interface to the world outside the component user interface, hardware monitor or drivers, and links to other components. This process provides a horizontal layering of the component. 

Of the analytical techniques available for process analytical measmements, IR is one of the most versatile, where all physical forms of a sample may be considered - gases, liquids, solids and even mixed phase materials. A wide range of sample interfaces (sampling accessories) have been developed for infrared spectroscopy over the past 20 to 30 years and many of these can be adapted for either near-lme/at-lme production control or on-line process monitoring applications. For continuous on-line measurements applications may be limited to liquids and gases. However, for applications that have human interaction, such as near-line measurements, then all material types can be considered. For continuous measurements sample condition, as it exists within the process, may be an issue and factors such as temperature, pressure, chemical interfer-ants (such as solvents), and particulate matter may need to be addressed. In off-line applications this may be addressed by the way that the sample is handled, but for continuous on-line process applications this has to be accommodated by a sampling system. 

In an attempt to overcome the significant difficulties that the presence of water vapor poses to the analysis of very volatile compounds, purge-and-membrane extraction techniques have been developed that largely prevent the introduction of water into the analytical system. Typical implementations of this form of sample introduction have been called by its developers membrane extraction with a sorbent interface (MESI),97 or membrane introduction mass spectrometry (MIMS).98 " They are based on a silicone hollow-fiber membrane that is inserted into the sample to be monitored, and the passing of a certain volume of inert gas through the membrane. Volatile compounds permeate the membrane and are swept to the adsorbent trap from which they are desorbed into the GC. This method of sample introduction is particularly suited for field and process monitoring and for dirty samples, since it prevents any nonvolatile compounds from entering the analytical system.100... 

It is normal practice for the system nsers (i.e., process operators) to interact with the system throngh the nser interface (panel, monitor) in order to initiate the process and respond to alarms. 

A Norvilas, A Negiz, J DeCicco, and A Cinar. Intelligent process monitoring by interfacing knowledge-based systems and multivariate statistical monitoring. J. Process Control, 10(4) 341-350, 2000. 

I. Technology What role will technology play An example is interfacing process control computers to a computerized maintenance management system (CMMS) for integrated condition monitoring, which will lead to a sound predictive maintenance program. 

Advances in spectroscopy are needed to evaluate the interface between the matrix and the fiber, plate, or particulate filler in composite materials and to improve nondestructive testing and process monitoring. 

With the rapidly increasing processing power of computers, improved operator interfaces and distributed control systems improved overall controls available to processors. Real-time process and product data and SPC tools became much more accessible and better utilized. However, in this period, perhaps the two most important factors affecting the adoption of process monitoring and control strategies have been... 

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