Microcomputer-based Control System Research Articles

Application of Microcomputer-Based Control System to Instantaneous Gas Water Heater

There is an increasing demand for high quality hot water supply equipment which will provide hot water at the exact desired temperature, save energy, save space, and which has easy operation.

Microcomputer-Based Controls for Continuous Casting

The continuous casting of steel eliminates many processing steps, thus allowing savings in time, energy, and processing costs. In this process a moving strand of steel is partially solidified in a water-cooled mold and subsequently cooled to complete solidification by intensive-cooling water sprays. Control of the cooling sprays is complex, requiring distributed control techniques, which are not readily implemented by analog means. Therefore, digital computer control systems have been developed for this purpose. In the past these systems have used a minicomputer in a supervisory control mode to provide optimum water-flow setpoints to conventional proportional plus integral analog controllers. This approach has given satisfactory results, but initial hardware and software costs have been high, and maintenance requirements, particularly in the computer/controller interface hardware, have been excessive. US Steel is currently testing a microcomputer-based control system which has the potential for resolving these problems. This system provides all the control features normally used as well as direct digital control (ddc) of cooling water flows, thus eliminating the need for analog controllers. Experience to date indicates that this new approach will provide increased reliability along with a significant reduction in equipment and maintenance costs.

A microcomputer based control system for antenna measurements

Describes the automatic control of antenna radiation pattern measurements by an ITT 2020 microcomputer. The system uses stepper motors rather than synchronous motors to control azimuth, elevation and polarisation positioners, eliminating the need for position angle transducers. Position angle information for reference and cross checking purposes is provided by up to four opto-switches on each positioner. System control and monitoring is efficiently carried out using one VIA on the computer. The system is relatively simple and very versatile.

Application of Micro-Computer Technologies in the Food and Allied Industries

CFPRA has identified several areas within the food industry where the use of modern micro-computer technology is likely to improve product quality and process efficiency. The use of real-time computation and computer logic enables mathematical modelling techniques to be used for process control, thus parameters may now be controlled although they may not be measured directly. This paper deals with the application of a micro-computer based control system to the problem of retort control via FO value and describes the capabilities of the system, plant interfacing, instrumentation and the implications of ‘derived-value control’.

A Microcomputer-Based Commutation Failure-Free Control System for the Cascaded Rectifier Circuit

A Z80 microcomputer-based control system for the cascaded single-phase rectifier circuit is presented. The cascaded rectifier circuit is composed of two thyristor bridges, that is, one is the conventional bridge and the other thyristor bridge with forced commutation. This circuit configuration is adopted to improve the input power factor. The system uses the microcomputer to generate the required firing pulses to the thyristors and to monitor the commutating process. Once the commutation failure is detected, the gating sequence is changed to return the system to the normal condition, thus realizing the commutation failure-free thyristor converter.

Control System for Centrifugal Compressor Energy Saving

Centrifugal compressors are to be provided with adjustable inlet vanes and diffuser vanes at each stage to perform the energy saving operation in the whole range of flow rate. A new method to control the vanes is developed which is composed of Reference Method to achieve the desired flow rate exactly and Trial Search Method to achieve a higher efficiency in spite of changes and disturbances. The proposed method is implemented on a microcomputer-based control system. This system is proved to be effective by experiments with a full-scale compressor.

Microcomputer-Based Laser Control and Synchronization System

The paper constitutes an applications case study involving the design of a microcomputer-based control and synchronization system of two lasers. The main performance specification is that the laser pulses should be synchronized within less that 10ns delay between them to achieve maximum power output. This specification has been achieved in the system designed in the project, constructed and tested in practice. An alternative of using off-the shelf instrumentation for the same purpose has been considered and rejected because of higher cost. The hardware configuration and the system software are described in the paper along with some basic design considerations and decisions implemented in the system's development

Application of a Distributed Microcomputer Based Control System in a New Petrochemical Plant

The paper deals with the selection and the design of process control systems based on distributed microcomputers for a large petrochemical complex. Taking into account the experiences gained in numerous process computer applications at PCK Schwedt a realistic control conception is presented using the potential advantages of the modern digital control hardware to the possible extent. Emphasis is given to such aspects as man-plant interface, control room design, local distribution and functional assignment of hardware, coexistence of conventional and modern technologies, reliability.

G10.2 : Programming of Control Functions in a Microcomputer Based Control System

The software system for a distributed digital instrumentation system is described. The system is intended for applications in the process industry and could be used for direct digital control, sequence control, protection systems, interlocks and alarming systems. The application programming is performed with an user oriented language of the “fill in the blanks” type. The language specified makes it easy for process engineers with no experience in computer programming to program wanted control functions

Energy Conservation in an Air Conditioning Installation Through a Microcomputer-Based Control System

An energy saving control system based on a microcomputer is developed for a central air-handling installation as can be applied in air conditioning systems. Using measured values of the conditions of the air at several places in the system and the measured outdoor climate variables, the microcomputer at regular intervals predicts the thermal response of the building to external load variations. With the information obtained those control actions are generated, which will result in a comfortable indoor climate with the least possible energy consumption. Thus, instead of applying a fixed control system, for each environmental condition the most appropriate control scheme is defined and put into operation. This type of control requires repeated numerical calculations and logic decissions, which can not be realized without the use of a computer. The installation and its control system are set up in the laboratory after a computer simulation test was carried out. Besides the control procedure, as applied in the system, an other equivalent possibility will be discussed

A microcomputer based control system for solar parabolic collectors

A microcomputer based control system for solar parabolic collectors

A Distributed System Adaptive Control Strategy

One attitude control device being studied for large spacecraft consists of two counter-rotating rings, each designated as an annular momentum control device (AMCD), that are attached to a spacecraft using several magnetic bearings distributed along the circumference of the rings. For large spacecraft large rings are desirable. Unfortunately, for large rings flexibility is appreciable and it becomes necessary to account for the distributed nature of the rings in the design of the magnetic bearing controllers. Also ring behavior is unpredictably sensitive to ring termperature, spin rate, manufacturing imperfections, and other variables. For that reason a distributed adaptive microcomputer-based control system is being sought for ring stabilization and maneuvering. An original adaptive-control methodology for distributed-parameter systems is detailed and application to spinning ring, i. e., AMCD, stabilization is used as an illustration. The proposed methodology, presented as a step-by-step procedure, combines a lumped-parameter expansion description of distributed parameter systems with a fundamental simultaneous identification and control strategy. Simulations are presented providing preliminary evidence of the capabilities of the proposed procedure.

A microcomputer based control system for the artificial heart.

A microcomputer based control system for the artificial heart.

A microcomputer-based control and communication system for the severely disabled

A microcomputer-based environmental control and communication system for the severely disabled has been developed. By puffing and sipping on a tube the user can store messages in computer memory and control a number of peripheral devices. A scanning method of operation is employed in which characters are selected for message building or control purposes from lists displayed on a CRT. An interface system is presently being developed to allow the computer to control peripheral devices by transmitting coded signals over the power mains.

A Distributed Microcomputer Control System for a High-Energy Gas-Laser Facility

Laser research facilities, with their typically severe EMI environment and attendant need for minimum length data links, represent an ideal application for a distributed microcomputer-based control system. This paper presents the conceptual design of a distributed control system for the High Energy Gas Laser Facility (Figure 1). Third in a series of experimental CO2 laser fusion systems at Los Alamos Scientific Laboratory in New Mexico, the HEGLF is aimed at exploring the use of lasers in thermonuclear research for power generation. As presently conceived, the system will contain multiple microcomputers, each with its own executive, performing dedicated functions under supervision of a central minicomputer. It will monitor six power amplifiers, the high-voltage pulse-power system, the laser preamplifiers, and the target systems, as well as automatically align the laser beams onto the target. System components, which will be distributed throughout the facility, will be interconnected via fiber-optics cables so as to combat the electromagnetic noise environment when the laser is fired.

Microcomputer-Based Control and Data Collection for a Mass Spectrometer

A microcomputer-based data acquisition and control system for a mass spectrometer was designed and built. This system incorporates commercially available microcomputer logic modules interfaced to various input and output devices; these devices include an IBM-compatible magnetic tape transport. The system operates from programs stored in firmware (permanent software) and can be programmed via a Teletype for several days of unattended operation. This report describes only the electronics for the system.