This work is carried out with the aim of developing a digital data transfer technique between a PC and PLC to provide for the development and testing of multi-actuator fluid power simulation models. Several methods of...
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This work is carried out with the aim of developing a digital data transfer technique between a PC and PLC to provide for the development and testing of multi-actuator fluid power simulation models. Several methods of encoding/decoding techniques have been developed and tested using simulation modeling. At relatively low cost, substantial improvements in the development and testing of PLC control and monitoring software have been achieved which extend to the simulation of authentic industrial fluid power systems.
The objective of a control system is to maintain a device or process within a set of parameters for a period of time. If the process or device of interest is expensive and complex it is usually recommended that the co...
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The objective of a control system is to maintain a device or process within a set of parameters for a period of time. If the process or device of interest is expensive and complex it is usually recommended that the control system for this process or device be tested on a process simulation before the control system is implemented in the field. Process simulators in the past have been highly specialized equipment built from discrete components and sub systems. Most of these simulators had a very limited application. Often the subsystems used to build the simulators had limited availability. This paper will present the use of a programmablelogic Control (PLC) system as a process simulator platform using a steam turbine simulation as an example. The discussion will include the development and implementation of the transfer functions in the PLC for the control valve, turbine, and speed feedback. The advantages and limitations of the PLC system for process simulation will be presented.
PLC-based systems are commonly designed according to a two-phase process: the system structure is conceived and detailed by the electro-mechanical project team, then the control project team is asked to design and dev...
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PLC-based systems are commonly designed according to a two-phase process: the system structure is conceived and detailed by the electro-mechanical project team, then the control project team is asked to design and develop the control software. Because of product complexity, different culture of the two teams, lack of supports to requirement specification and communication, and other problems, the design process presents heavy costs and times. The paper aims at presenting an approach for bridging the gap between the two design environments. It adapts and integrates two techniques resulting from European Union funded projects: a family-based product modelling technique from the ESPRIT project 8224 - RUMS (used in the structural design phase) and an object-oriented PLC specification language from the ESPRIT / ESSI project 10542 - EASIER (used in the software design phase).
programmablecontrollers were originally evolved as programmable logic controllers to be used solely for replacement of hardwired logic schemes. In the course of time the PLC hardware has become more powerful and prog...
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programmablecontrollers were originally evolved as programmable logic controllers to be used solely for replacement of hardwired logic schemes. In the course of time the PLC hardware has become more powerful and programmablecontrollers are taking their designated place deservingly in the upper range automation systems and handle some of the special control functions which were hitherto being executed only by process computers or analog controllers. The paper deals with automation of a single stand aluminium cold rolling mill using programmablecontrollers and PC's. It highlights the various special functions realized using the programmablecontrollers.
This paper describes a new deflection controller IC3) for monitors. It has full horizontal and vertical autosync capability and offers a comprehensive set of functions for raster correction, protection, and SMPS contr...
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This paper describes a new deflection controller IC3) for monitors. It has full horizontal and vertical autosync capability and offers a comprehensive set of functions for raster correction, protection, and SMPS control. As an outstanding feature, the IC utilizes automatic tracking between the external adjustments for picture size, picture position and raster correction. This combination of high integration level and well defined module interactions simplifies the design of modern autosync monitors.
This paper reviews the experiences of Bechtel Water Technology (formerly NWW Engineering), in the application of programmable logic controllers to projects which were designed and constructed on behalf of a major wate...
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This paper reviews the experiences of Bechtel Water Technology (formerly NWW Engineering), in the application of programmable logic controllers to projects which were designed and constructed on behalf of a major water & wastewater utility, NWW Ltd. The paper outlines how experience of industrial disputes followed by the introduction of EC Drinking Water Directives during the 1980's generated a requirement to build a substantial number of unmanned automated plants. This resulted in a substantial increase in the number and sophistication of process control solutions produced. It outlines the challenges encountered during the life cycle of these sophisticated solutions and continues by considering how, in addition to the control requirements other factors such as the investment regime, operational constraints, and manpower skill levels influence the design of PLC control systems and led to different solutions being proposed for the Water and Wastewater treatment plants. It identifies how by the use of dynamic modelling techniques the company has been able to focus the application of advanced technology only to the areas where it is specifically needed, thus allowing simpler control systems to be provided for the bulk of its treatment processes. The paper reviews the adoption of PLC systems with SCADA interfaces, in preference to DCS packages. Standardization on a single supplier for PLC systems is identified as an opportunity to reduce project costs by allowing the generation of standard control systems architectures and the production of standard portable software.
This paper proposes a new software design methodology for programmablecontrollers (PCs), using Sequential Function Chart (SFC) and Encapsulated Actuator Model of mechanical actuators. This methodology is expected to ...
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This paper proposes a new software design methodology for programmablecontrollers (PCs), using Sequential Function Chart (SFC) and Encapsulated Actuator Model of mechanical actuators. This methodology is expected to be applied to machines in the Factory Automation (FA) area of manufacturing industry. The concept reveals many advantages in design, testing, and maintenance. This paper also discusses future technical trends in PC's application in the areas of programming, simulation, and diagnosis of sequential control of machine.
The main purpose of this paper is to present the use of a synchronized colored Petri net model as the formalism to specify control for discrete event real time low cost programmablecontrollers (PLCs), integrating an ...
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The proceedings contains 6 papers on the application of advanced programmable logic controllers (PLCs) with specific experiences from water treatment. Topics discussed include fully automated waterworks, chlorination ...
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The proceedings contains 6 papers on the application of advanced programmable logic controllers (PLCs) with specific experiences from water treatment. Topics discussed include fully automated waterworks, chlorination control in large treatment works, PLC application as a cell controller using a communication network, sequential fluid power system condition monitoring using PLCs, and the use of PLCs to control rapid gravity filter operations.
Particularly in control applications involving programmable logic controllers (PLCs), the use of electronic operator interface (OI) devices has become popular. Several developments in industrial practices and resource...
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Particularly in control applications involving programmable logic controllers (PLCs), the use of electronic operator interface (OI) devices has become popular. Several developments in industrial practices and resources are influencing OI design and performance: rapid growth in smaller, more intelligent PLCs;increased use of networked PLCs;desire for more conveniently located operator control stations;greater familiarity with windows-based software packages;and new flat-panel display technologies. These developments, coupled with the users' demand for better OI quality, better design, greater variety in selection and better fit to user's needs, all drive today's industrial operator interface trends in hardware, software, and connectivity to PLCs.
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