Automated Instruments Process Control

Automated devices are widely used in process control systems, whereas automatic instruments of various sophistication are used in the analytical laboratory for performing analyses. The latter may perform all steps of an analysis, from sample pickup and measurement through data reduction and display. 

Automatic instruments improve tlie analyst s efficiency by performing some of the operations done manually. Automated instruments control a system based on the analysis results. 

Methods for process analysis. [From J. B. Callis, D. Ulman, and B. R. Kowalski, Anal. Chem., 59 (1987) 624A. Copyright 1987 by the American Chemical Society. Reprinted by permission of the copyright owner.] 

The use of analytical data for automated process control can save millions of dollars in improved production efficiencies and product quality. 

The measurement devices may be classed as continuous or discrete (batch) instruments. The continuous instrument constantly measures some physical or chemical property of the sample and yields an output that is a continuous (smooth) function of time. A discrete, or batch, instrument analyzes a discrete or batch-loaded sample, and information is supplied only in discrete steps. In either case, information on the measured variable is fed back to monitoring or control equipment. Each technique utilizes conventional analytical measurement procedures and must be capable of continuous unattended operation. 

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Automation of process control has created a need for continuous monitoring of the particle size of particulate matter in process streams. Some on-line particle size analysis instrumentation has been developed recently to meet this need it can initiate regulatory or shut-down signals in control systems. The basic requirements for such instrumentation are that it must operate automatically and continuously under preset instructions, and the response time from observation to readout must be so short as to be nearly instantaneous. 

Special, fully automated one-task XPS instruments are beginning to appear and will find their way into both quality control laboratories and process control on production lines before long. 

The purpose for which the analytical data are required may perhaps be related to process control and quality control. In such circumstances the objective is checking that raw materials and finished products conform to specification, and it may also be concerned with monitoring various stages in a manufacturing process. For this kind of determination methods must be employed which are quick and which can be readily adapted for routine work in this area instrumental methods have an important role to play, and in certain cases may lend themselves to automation. On the other hand, the problem may be one which requires detailed consideration and which may be regarded as being more in the nature of a research topic. 

Mechanization with process control, where process means a sequence of manipulations. One or several functions in an instrument may be automated. 

The character and the degree of automation in chemical control may have been covered in the above treatment of semi-automatic or completely automatic, and of discontinuous or continuous analysis, but something more should be said about the means by which automation proper has been performed in recent times. Whereas in the past automated analysis involved the use of merely, mechanical robots, to-day s automation is preferably based on computerization in a way which can best be explained with a few specific examples. Adjustment knobs have been increasingly replaced with push-buttons that activate an enclosed fully dedicated microcomputer or microprocessor in line with the measuring instrument the term microcomputer is applicable if, apart from the microprocessor as the central processing unit (CPU), it contains additional, albeit limited, memory (e.g., 4K), control logics and input and output lines, by means of which it can act as satellite of a larger computer system (e.g., in laboratory computerization) if not enclosed, the microcomputer is called on-line. 

Improved process control (monitoring and instrumentation) more automation... 

Automation has been applied for a number of years in process control instrumentation, but the major impetus to introduce automatic devices into laboratories stems from three sources (1) the introduction of the continuous-flow principles as outlined by Skeggs [1] (2) the general demand for clinical chemical measurements, which represents a ready and sizeable market for instrument companies, and, more importantly, (3) the abihty to handle large volumes of data and package them in a form suitable for presentation to analysts and customers, through the use of mini- and micro computer systems hnked to a control computer. 

The degree of the instrumentation of pharmaceutical unit operations has increased. This instrumentation provides information of the state of the process and can be used for both process control and research. A central part of optimizing production is increasing the level of automation. Besides... 

Process analytical applications differ from laboratory analytical applications in that the analyzer hardware and software are in a more hostile environment, the maintenance and operations personnel in the analyzer area are typically not trained like lab technicians, and the purpose of the analyzer is most often for rapid process control rather than troubleshooting. As a result, process analytical applications tend to focus more on automation, minimization of maintenance, and long-term reliability. In this more pragmatic context, the instrument specialization function of chemometrics is used even more exclusively than the information extraction function. 

In 1995, Taylor and co-workers also described the use of an open-access LC/MS system for routine structure confirmation, featuring atmospheric pressure chemical ionization (APCI). This system featured dual personal computers (PCs) for automated instrument control and sample log-in. A system-PC is responsible for running the Windows NT for Workgroups operating system and interfaces with the network for instrument control. A separate log-in PC, isolated from the LC/MS system, is used by the synthetic chemist to enter details about the samples. The analyst prepares the sample in an autosampler vial in one of several solvent options. The system specifies where to place the sample vial in the autosampler, and following analysis with a standard method, spectra are automatically processed and printed without any chemist intervention. 

With the use of high performance materials and automated instruments, protein separation is becoming a more controllable process. However, some problems persist even with the use of sophisticated instruments. Many difficulties are still found in determining the optimal extraction and purification conditions, as well as in selecting suitable methods for detecting the protein and quantifying its biological activity. 

Additional needed process equipment was evaluated, selected, purchased, and set up. Automation opportunities were defined, and process control instruments were tested, purchased, and installed. An existing clean (HEPA-filtered) area was upgraded for the final isolation of the dilevalol hydrochloride made in New lersey—this was needed to serve the requirements for the parenteral dosage form. 

Adler, D. J. (1998). Instrumentation and process control system strategy. In Automation and Validation of Information in Pharmaceutical Processing (J. F. DeSpautz, ed.), pp. 59-68. Dekker, New York. 

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