Instrumentation microcomputer

If at all possible, a laboratory bench or a table ca. 1 m high should be available at right angles to the vacuum frame, for ancillary equipment such as oscilloscopes, electrical instruments, microcomputers etc. and there should be within easy reach of the operator a bench or table for Dewar vessels, reagents, etc. 

This is a double-channel flaw detector having their own microcomputer with 1 Mbyte memory to store data of the LMA and the LF channels for 800...2000 m of a rope under inspection. The instrument can be used in two modes as a tester for operative inspection or as a device for the inspection data storage. 

Time Systems, McGraw-HiU, New York, 1985 Hawryszldewycs, Database Analysis and Design, Science Research Associates Inc., Chicago, 1984 Kham-hata, Microprocessois/Microcomputers Architecture, Software, and Systems, 2d ed.. Whey, New York, 1987 Liptak, Instrument Engineers Handbook, Chilton Book Company, Philadelphia, 1995 Melhchamp (ed.), Real-Time Computing with Applications to Data Acquisition and Control, Van Nostrand Reinhold, New York, 1983. 

The methods dependent upon measurement of an electrical property, and those based upon determination of the extent to which radiation is absorbed or upon assessment of the intensity of emitted radiation, all require the use of a suitable instrument, e.g. polarograph, spectrophotometer, etc., and in consequence such methods are referred to as instrumental methods . Instrumental methods are usually much faster than purely chemical procedures, they are normally applicable at concentrations far too small to be amenable to determination by classical methods, and they find wide application in industry. In most cases a microcomputer can be interfaced to the instrument so that absorption curves, polarograms, titration curves, etc., can be plotted automatically, and in fact, by the incorporation of appropriate servo-mechanisms, the whole analytical process may, in suitable cases, be completely automated. 

Note. Most instruments now include a microcomputer which stores the calibration curve and allows a direct read-out of concentration. 

T.F. Niemann, M.E. Koehler, and T. Provder, "Microcomputers Used as Laboratory Instrument Controllers and Intelligent Interfaces to a Minicomputer Timesharing System," in Personal Computers in Chemistry> p- Lykos, Ed,... 

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. 

In 1976, Radiometer61 presented for the first time a microprocessor-controlled titration system. Since then, the microprocessor has been used preferentially and as a fully integrated part (in line) in electroanalytical instruments as a replacement for the on-line microcomputer used before. Bos62 gave a comprehensive description of the set-up and newer developments with microprocessors in relation to microcomputers and indicated what they can do in laboratory automation. Many manufacturers are now offering versatile microprocessor-controlled titrators such as the Mettler DL 40 and DL 40 RC MemoTitrators, the Metrohm E 636 Titroprocessor and the Radiometer MTS 800 multi-titration system. Since Mettler were the first to introduce microprocessor-controlled titrators with their Model DK 25, which could be extended to a fully automated series analysis via the ST 80/ST 801 sample transport and lift together with the CT 21/CT211 identification system, we shall pay most attention to the new Mettler MemoTitrators, followed by additional remarks on the Metrohm and Radiometer apparatus. 

A dedicated microcomputer is interfaced to the Instron instrument in order to collect the raw data. The microcomputer consists of an 8080A microprocessor, 32K bytes of memory, A/D converter, serial I/O for communication, parallel I/O for digital control and sensing, a real-time programmable clock, and vectored interrupt control. 

The distinction between mini - and microcomputers is becoming essentially one of size and price. Minicomputers, which use 16- or 32-bit words, had much larger memories than microcomputers and could be used for the control of several laboratory instruments on a time-sharing basis. However, microcomputers are becoming ever more powerful. Although some still use 8-bit words, 16-bit and 32-and 64-bit word machines are becoming stan-... 

The following examples are intended to illustrate some of the current capabilities of instruments under microprocessor control or interfaced to a dedicated microcomputer. These capabilities are becoming more sophisti-... 

New methods can be created by automatic optimization of parameters during a trial run and all methods can be stored permanently in a non-volatile area of memory which is preserved even when the instrument is switched off. Some instruments provide a means of producing first and second derivatives of the titration curve (p. 243) which can be advantageous where the end-point is indistinct or there is more than one end-point to be detected. Titrators with a substantial amount of RAM incorporate what is in effect a dedicated microcomputer. 

Most electronic technology systems use digital electronics in conjunction with microcomputer technology to allow the instrumentation user to calibrate and troubleshoot the instrumentation from either a local or remote location. This capability is commonly referred to as "Smart" electronic technology. 

UV/visible 200-750 Cecil Instruments CE 594 (microcomputer controlled) Double High... 

Double beam spectrophotometers are being manufactured by various well-known manufacturers across the world, such as SUMADZU VARIAN CECIL BECKMAN PERKIN ELMER etc., to name a few. These instruments are mostly based on microcomputer-controlled devices with built-in recorder to accomplish faster speed and greater operating stability. 

The presence of a lag period in many coupled assays and difficulties in determining the linear portion of a curve present the main problems in the calculation of enzyme activity using reaction rate analysers. In the simplest instruments the slope of the curve in the first few seconds of the reaction is extrapolated into a straight line or, if the reaction is known to show a lag period, the rate of reaction after a defined period of time can be measured. The more sophisticated instruments use microcomputers to determine the linear portion of the curve and calculate the enzyme activity directly from the slope. The second derivative of the reaction progress curve (rate of change of the slope) can be monitored by the computer and when a value of zero is held for a period of time (10—15 seconds) this indicates a linear section of the graph. From the value for the slope, the enzyme activity can be calculated. 

Additionally, use of a commercial AI shell for expert system development has been demonstrated without the need to learn computer programming languages (C, Pascal, LISP or any of its variations), nor to have an intermediary knowledge engineer. Although this development effort of 4-5 man months was on a minicomputer, adaptation of EXMAT to the microcomputer version of TIMM is anticipated. The completed implementation of EXMAT will support the belief that AI combined with intelligent instrumentation can have a major impact on future analytical problem-solving. 

A Waters Model 150C ALC/GPC was interfaced to a minicomputer system by means of a microcomputer for automated data collection and analysis. Programs were developed for conventional molecular weight distribution analysis of the data and for liquid chromatographic quantitative composition analysis of oligomeric materials. Capability has been provided to utilize non-standard detectors such as a continuous viscometer detector and spectroscopic detectors for compositional analysis. The automation of the instrument has resulted in greater manpower efficiency and improved record keeping. 

Automated data analysis for the chromatograph is achieved by interfacing the instrument and detectors to a microcomputer for data acquisition. The microcomputer is connected to the Intelink... 

Before initiating an analysis, the instrument must be programmed for automatic operation and the samples placed in the appropriate positions of the injector. Dialog 16, shown in Figure 2, starts operation of the microcomputer. Intelink communication with the instrument is established and the parameters for the first sample are taken from the sample definition file on the minicomputer and are transmitted to the microcomputer. The microcomputer turns on a ready status light at the instrument to signal to the operator to begin automatic operation of the instrument. 

The second stage is data acquisition. This stage is entered when the operator starts the instrument. The instrument makes the first injection and signals the microcomputer via Intelink. After a delay proportional to the void volume of the column set, data are collected on a time basis (constant flow rate assumed) at the predetermined rate from each of the detectors selected, up to a maximum of three simultaneous detectors. VHien the sample run is complete, the instrument again signals the microcomputer which places the instrument in a hold state while it reads the operational parameters from the instrument for that sample and... 

Niemann, T. F. Koehler, M. E. Provder, T. "Microcomputers used as Laboratory Instrument Controllers and Intelligent Interfaces to a Minicomputer Timesharing System" in "Persona] Computers in Chemistry" Lykos, P., Ed. John Wiley and Sons New York, 1981 pp. 85-91. 

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