Microcomputer-based Data Acquisition System Research Articles

Microcomputer control of infrared detector arrays used in direct imaging and in Fabry-Perot spectroscopy

A microcomputer-based data acquisition system has been developed for astronomical observation with two-dimensional infrared detector arrays operating at high pixel rates. The system is based on a 16-bit 8086/8087 microcomputer operating at 10 MHz. Data rates of up to 560000 pixels/s from arrays of up to 4096 elements are supported using the microcomputer system alone. A hardware co-adder under development permits data accumulation at rates of up to 1.67 million pixels/s in both staring and chopped data acquisition modes. The system has been used for direct imaging and for data acquisition in a Fabry-Perot spectrometer. The hardware is operated using interactive software which supports the several available modes of data acquisition and permits data display and reduction during observing sessions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A microcomputer based data acquisition system for hot wire anemometry

A microcomputer based data acquisition system for hot wire anemometry has been developed as an alternative to conventional analogue systems. The system is capable of acquiring data on four channels simultaneously at acquisition rates of up to 13 kHz with 12 bit resolution. Subsequent processing of the data is performed by software and enables the calculation of mean velocity, Reynolds normal and shear stresses, autocorrelation coefficient, integral time and length scales, and Fast Fourier Transform of the turbulence quantities. Compared with the conventional analogue systems, the digital system offers significant advantages in cost, flexibility, convenience, and immunity from electrical noise and drift.

A Microcomputer-Based Data Acquisition System and Software for Thermal Studies

A data acquisition system used for temperature and mass concentration measurements is described. Data logging devices interfaced with a microcomputer are shown to offer a large data collection capacity suitable for transient measurements. Additional hardware required to interface conductivity probes to a microcomputer via a commercially available data logger is illustrated. Practical details on software to facilitate the data communication is described, and software for data reduction written in the C programming language is also provided.

Gathering of daily instantaneous global solar radiation using a microcomputer-based data acquisition system

A microcomputer-based system for gathering of daily instantaneous global solar radiation is presented. Daily solar flux data are automatically recorded and stored in the computer hard disk. The microcomputer, interfaced to a data acquisition system, also records the meteorological data simultaneously. The data gathered can be used to study the short-duration fluctuations in sunlight caused by clouds, its effect in the evaluation of solar collector performance, and the relative frequency histograms of total solar radiation at specified levels.

A high speed data acquisition and analysis system for ultrasonic energy measurements

A high-speed microcomputer-based data acquisition and analysis system was designed and constructed. The system was interfaced to an ultrasound sector scanner. The primary application of the system, in this case, was to measure the power spectrum of the backscattered (low-level) ultrasound signal from acoustic inhomogeneous media, such as liver tissue. The system was bench-tested and then tested successfully in normal operative conditions. The system digitizes the ultrasound signal, with sample rate of 16 Msample/s and stores the digitized data in a temporary storage (static random-access memory). When the temporary storage is full, the data is transferred to a microcomputer, where a fast Fourier transform algorithm is applied to calculate the power spectrum of the ultrasound signal. Pattern-recognition algorithms are applied to differentiate between normal and abnormal liver tissues using the acoustic attenuation coefficient as the differentiation feature.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Microcomputer-based data acquisition system for transient studies in hydrology

The implementation of a microcomputer-based data acquisition system for transient studies in hydrology is presented. The system can be used with a sand tank model or an electrical analog model. The software and hardware aspects of the system are discussed and some preliminary results are presented.

Induction Motor Identification by a Microcomputer-Based Structure

The paper deals with the parameter estimation of an induction motor performed through a microcomputer-based data acquisition system and recursive identification algorithms (RLS and RGLS) implemented by means of a general purpose computer. The microcomputer-based data acquisition system is essentially made by connecting the Z80 CPU with its peripherals and auxiliary memories through a bus standard. The motor is represented by a classical fifth-order model linearized around a usual working point; an approximate third-order model, obtained via balanced realization, is in good correlation with the original one according to the identification aims and to the measurement set efficiency. An original CAD procedure is utilized to determine the electrical parameters.

The automation of an interfacial tensiometer

Interfacial tension at a liquid-liquid interface is an important property of immiscible liquid mixtures, such as in chemical emulsion processes. Quantitative measurement of interfacial tension most often requires the use of specialized laboratory equipment which is not readily adaptable to on-line use. In order to continuously monitor an interfacial tension-dependent process, an automated device based on a relatively simple method of determination would be preferable. A drop-weight method of interfacial tension determination, based on a static force balance of a drop of one phase suspended from a capillary tip and surrounded by the second phase, has been chosen as the basis for an automated interfacial tensiometer. The principal purpose of the device is to measure, with a microcomputer-based data acquisition system, flow rate and drop frequency of the disperse phase, in order to calculate the primary unknown parameter of a drop-weight equation — the drop volume. The device has been successfully tested over the range of interfacial tensions of 0.1 to 50 dynes cm −1 using various liquid-liquid systems.

Experimental study of thermally stratified unsteady flow by NMR-CT

Thermally stratified unsteady flow caused by two-dimensional surface discharge of warm water into a rectangular reservoir is investigated. Experimental study is focused on the rapidly developing thermal diffusion at small Richardson number. The basic objectives are to develop a measurement system for the unsteady flow phenomena and to study the interfacial mixing between a flowing layer of warm water and the underlying body of cold water. Mean velocity field measurement is carried out by using NMR-CT (Nuclear Magnetic Resonance — Computerized Tomography). It detects a quantitative flow image of any desired section in any direction of flow. Transient mean temperature profiles are obtained by fine thermocouple arrays and a microcomputer-based data acquisition system. Results show that the warm layer penetrates more rapidly into the cold layer at smaller Richardson number because of decrease instability. This is clearly verified by flow visualization using thymol blue solution. It is found that the transport of heat across the interface is more vigorous than that of momentum.

Microcomputer Based Data Acquisition System for Dynamic Testing

The availability of capable and relatively inexpensive microcomputers and versatile expansion devices has revolutionized education, research, and practice in engineering. A data acquisition and analysis system for use in full scale and large model dynamic testing based on a popular series of microcomputer has been developed. “Quick-look” and preliminary frequency analysis of data are completed in the microcomputer environment, while more detailed frequency domain analysis of single and dual channel data are completed in the mainframe environment. The system has been used for ambient and forced vibration testing of several prototype structures and large models.

Particle size distribution in oil-water dispersions using image processing

Image processing technique has been applied to measure drop size distribution of oil in water dispersions, using a microcomputer based data acquisition system. The results obtained indicated quite good agreement with those obtained manually using microphotography. This technique is particularly useful for cases with low contrast to the background.

The automation of an interfacial tensiometer

Interfacial tension at a liquid-liquid interface is an important property of immiscible liquid mixtures, such as in chemical emulsion processes. Quantitative measurement of interfacial tension most often requires the use of specialized laboratory equipment which is not readily adaptable to on-line use. In order to continuously monitor an interfacial tension-dependent process, an automated device based on a relatively simple method of determination would be preferable. A drop-weight method of interfacial tension determination, based on a static force balance of a drop of one phase suspended from a capillary tip and surrounded by the second phase, has been chosen as the basis for an automated interfacial tensiometer. The principal purpose of the device is to measure, with a microcomputer-based data acquisition system, flow rate and drop frequency of the disperse phase, in order to calculate the primary unknown parameter of a drop-weight equation — the drop volume. The device has been successfully tested over the range of interfacial tensions of O.l to 5O dynes cm −1 using various liquid-liquid systems.

A microcomputer-based data acquisition and analysis system. Application to EPR

We present a data-acquisition system which is easily rearranged for various experiments. Minimal effort has been required for the hardware part and the general architecture of the system provides for easy acceptance of all types of analog or digital signals. A disk operating system reserved to spectra storage has been created. Another interesting feature is the facility with which the software can be modified by use of relocatable machine-language routines. An application to EPR spectrometry is presented as an illustration of the versatility and speed offered by the software development.

MICROCOMPUTER CONTROL OF SPECTROSCOPIC INSTRUMENTS

ABSTRACT A small, versatile microcomputer-based data-acquisition system has been developed for astronomical observing in the infrared. The hardware is a 16-bit 8086/8087 based system which has been tailored for use in spectroscopic observing programs. The hardware is operated using interactive software which permits high-speed data acquisition and real-time analysis of spectroscopic data. The combined hardware and software system facilitates flexible, efficient, and uniform operation of a variety of spectroscopic instruments. Key words: microcomputers-spectroscopic instruments

MICROCOMPUTER CONTROL OF INFRARED DETECTOR ARRAYS

ABSTRACT A microcomputer-based data-acquisition system has been developed for astronomical observing with two-dimensional infrared detector arrays. The hardware used is a 16-bit, 8086/8087 based system operating at 8 MHz. Data rates of up to 454,000 pixels per second are supported. The hardware is operated using interactive software which supports several modes of data acquisition.

A microcomputer-based data acquisition system for a prosthetic heart valve test apparatus.

The hydrodynamic testing of prosthetic heart valves in the laboratory under pulsatile flow conditions remains the only way of obtaining detailed information about valve function. Test procedures have become increasingly sophisticated, with a variety of different test conditions and detailed analysis of the pressure and flow signals. A computerized data acquisition system has been developed for use with the Glasgow pulsatile flow test apparatus. The computer collects seven signals from the test rig over a period of 20 s, and calculates the average waveform for each signal. Standard parameters, such as mean pressure differences, mean flows, regurgitant volumes and energy losses, are calculated automatically. The complexity of the analysis and the need for standardized documentation makes computerization essential. The system has been used extensively for function tests on over 160 prosthetic heart valves.

A Microcomputer Based Data Acquisition System for High Impedance Fault Analysis

Investigation of High Impedance Faults has long held a high priority at Pennsylvania Power & Light Company (PP& L). The Ratio Ground Relay has been developed in conjunction with Westinghouse Electric Corporation's Advanced Systems Technology and Relay Instrument Divisions under PP&L sponsorship. As part of the research, six feeders were digitally modeled [1], one feeder was modeled on an analog computer [2], and staged fault tests [3] were conducted to gain data and observe relay operations under controlled conditions. Thorough development and analysis of the applicability of a new relaying technique requires long-term field testing. To ensure that the devices are performing according to design specifications, they must be monitored. This paper describes the analysis of four such monitoring schemes and discusses the unique application of commercially available home microcomputer equipment within the substation environment to automatically sample, record and transmit circuit data to a host microcomputer. It also describes the computer configuration, programming, and data transfer to the corporate mainframe computer. The Ratio Ground Relay and a conventional Ground Overcurrent Relay have been installed on one feeder from each of six substations to evaluate their performance during normal distribution system daily operation. The development of this unique microcomputer application is discussed in detail.

A Microcomputer Based Data Acquisition System for High Impedance Fault Analysis

Investigation of High Impedance Faults has long held a high priority at Pennsylvania Power & Light Company (PP& L). The Ratio Ground Relay has been developed in conjunction with Westinghouse Electric Corporation's Advanced Systems Technology and Relay Instrument Divisions under PP&L sponsorship. As part of the research, six feeders were digitally modeled [1], one feeder was modeled on an analog computer [2], and staged fault tests [3] were conducted to gain data and observe relay operations under controlled conditions. Thorough development and analysis of the applicability of a new relaying technique requires long-term field testing. To ensure that the devices are performing according to design specifications, they must be monitored. This paper describes the analysis of four such monitoring schemes and discusses the unique application of commercially available home microcomputer equipment within the substation environment to automatically sample, record and transmit circuit data to a host microcomputer. It also describes the computer configuration, programming, and data transfer to the corporate mainframe computer. The Ratio Ground Relay and a conventional Ground Overcurrent Relay have been installed on one feeder from each of six substations to evaluate their performance during normal distribution system daily operation. The development of this unique microcomputer application is discussed in detail.

Microcomputer based data acquisition systems for centrifuge modeling : Shen, C K; Li, X S; Kim, Y S Geotech Test JV7, N4, Dec 1984, P200–204

Microcomputer based data acquisition systems for centrifuge modeling : Shen, C K; Li, X S; Kim, Y S Geotech Test JV7, N4, Dec 1984, P200–204

Identification of an Induction Motor by a Microcomputer based Structure

Abstract The paper deals with the parameter estimation of an induction motor performed through a microcomputer based data acquisition system and recursive identification algorithms (RLS and RGLS) implemented by means of a general purpose computer. The microcomputer based data acquisition system is essentially made by connecting the Z80 CPU with its peripherals and auxiliary memories through a bus standard. The motor is represented by a classical 5th order model linearized around a usual working point; an approximate 3rd order model, obtained via balanced realization, gives very good agreement with the original one according to the identification aims and to the measurement set efficiency The motor estimation is performed through recursive algorithms in unified forin according to the discrete model structure. Finally an original CAD procedure is utilized to determine the electrical parameters.