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Process user-adjustable system

We use a simple liquid level controller to illustrate the concept of a classic feedback control system.1 In this example (Fig. 5.1), we monitor the liquid level in a vessel and use the information to adjust the opening of an effluent valve to keep the liquid level at some user-specified value (the set point or reference). In this case, the liquid level is both the measured variable and the controlled variable—they are the same in a single-input single-output (SISO) system. In this respect, the controlled variable is also the output variable of the SISO system. A system refers to the process which we need to control plus the controller and accompanying accessories such as sensors and actuators.2... [Pg.82]

Another important aspect during the development in the laboratory is that the plant set-up changes frequently. Hence it is highly desirable to work with a flexible and self-explanatory PCS system which is fully adjustable by the user to any specific process set-up. For this purpose, modular built-up software based on the computer language LabView , often used for laboratory applications, was developed and combined with also modular constructed hardware [77]. [Pg.579]

For brevity, further discussion is restricted to the spatial discretization used to obtain ordinary differential equations. Often the choice and parameters selection for this methods is left to the user of commercial process simulators, while the numerical (time) integrators for ODEs have default settings or sophisticated automatic parameter adjustment routines. For example, using finite difference methods for the time domain, an adaptive selection of the time step is performed that is coupled to the iteration needed to solve the resulting nonlinear algebraic equation system. For additional information concerning numerical procedures and algorithms the reader is referred to the literature. [Pg.249]

With active systems, the controls are mostly automatic, heat flows are well contained, and heat transfer processes are accrrrately predictable. With passive systems, heat flows are more diffuse and complex interchanges occttr, which can be grossly influenced by user interference. Often the appropriate adjustment of controls (e.g., of shading devices or of Trombe-wall vents) by the user at the right time is reqtrired to achieve optimttm performance of the system. Both the competence and the attitude of the user can drastically influence the resrrlts. [Pg.231]

Effectiveness of transport system embraces different aspects. Individual users perceive differently advantages and costs of transport. In the assessment process it is essential to have possibility of selection of options of infrastructure adjustment to perform transport tasks. The complexes of decisions affect the effectiveness of integrated transport systems (Leontiadis et al. 2011). [Pg.560]

Model update functions provide users the possibility to change, update and reconfigure the BBN model intuitively. The original generic BBN model can be adjusted based on the specific requirements of the R MM for a certain industrial system or process. After the update, the new model can be saved and utihzed for future application. [Pg.822]


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