essentials of process control solution

... 61285 (1994) Industrial-process control – Safety of analyzer houses 61297 (1995) Industrial-process control systems – Classification of adaptive controllers for the purpose of evaluation 61298-1 ... pneumatic signal for process control systems Expression of performance of air quality infra-red analyzers 60534: — Industrial-process control valves 60534-1 (1987) Part 1: Control valve terminology ... industrial-process measurement and control equipment in oxygen service Industrial-process measurement and control – Terms and definitions Binary direct voltage signals for process measurement and control

Ngày tải lên: 04/04/2014, 11:29

... Before looking at the variety of plots available, let us remind ourselves of the object of the exercise We have a system that we believe will benefit from the application of feedback Before “closing ... a question of the location of the poles of a system, with disaster if any pole strayed to the right half of the complex frequency plane Where will we find the poles of the closed loop system? ... square of its modulus to m, use Equation 11.3 to derive the equation of the locus of the M-circles in G. We see that we have a safely stable system, although the gain peaks at a value of 2.88

Ngày tải lên: 21/06/2014, 07:20

... be generated in terms of a few lines of software If we were meticulous, we could find a lot of unanswered questions about the stability of the simulation, about the quality of Trang 2the approximation ... understanding of underlying principles of functions of time and the way that dynamic systems affect them In fact, many of the issues of convolution can be much more easily be explored in terms of discrete ... the “meaning” of functions We could think of x(t) as a simple number, the result of substituting some value of t into a formula for computing x. We can instead expand our vision of the function

Ngày tải lên: 21/06/2014, 07:20

... a direction of any of the columns of AB But there is more The A matrix can send each of these new displacements in the direction A2B , then A3B and so on forever So to test for controllability ... the direction of that single column vector of B If there are two inputs then B has two columns If they are independent the state can be sent in the direction of any combination of those vectors ... enough can be seen by examining the rows of C, of CA and so on, or more formally by testing the rank of C CA CA CA and ensuring that it is the same as the rank of the system Showing that the output

Ngày tải lên: 21/06/2014, 07:20

... z-transform of g(n), then if we let z tend to 1 the value of G(z) will tend to the sum of all the elements of g(n) If we can construct g(n) to be the differ-ence between consecutive elements of f(n), ... limit of this when N is taken to infinity is the final value of f(n) So what is the relationship between G(z) and Far from being the “poor cousin” of continuous control, discrete time control ... ◾ Essentials of Control Techniques and TheoryWe would also like to look closely at reduced-state observers, perhaps to find the equivalent of phase advance Now we set up a system within the controller

Ngày tải lên: 21/06/2014, 07:20

... have assumed that the goal of the controller is to bring the error to zero in the absence of any other input This is an oversimplification, since the objective of many controllers is to combat ... has been driven to zero—or until the limit of maximum drive is reached Many principles of controller design have arisen from the needs of gunnery A controller containing one integration can reduce ... is a hope of achieving dead-beat correction of the offset, instead of the slow exponential decay resulting from continuous integral feedback Now we must investigate the various forms of disturbance

Ngày tải lên: 21/06/2014, 07:20

... involving sums of squares of combinations of states, added to sums of squares of mixtures of inputs. We can exploit matrix algebra to express this mess more neatly as the sum of two quadratic ... required sum of squares and cross-products. e diagonal elements of R give multiples of squares of the u’s, while the other elements define products of pairs of inputs. Without any loss of generality, ... system’s behavior with and without control. By applying a battery of mathematical tools we can devise controllers that will meet a variety of objectives, and some of them will actually work. Other

Ngày tải lên: 21/06/2014, 07:20

... expedi-ent way to control a throwaway consumer product So where should the design of a controller begin? There must first be some specification of the performance required of the con-trolled ... computer that applies the control, it is the control strat-egy that counts, rather than the size of the system A radio-telescope in the South of England used to be controlled by two mainframes, ... sensors and actuators that are fundamental to many of the control decisions Let us try to put them into some sort of order of complexity By orders of magnitude, the most common sensor is the thermostat

Ngày tải lên: 21/06/2014, 13:20

... direct-synthesis controllers The basic idea is to specify the desired response of the system to a particular type of disturbance and then, knowing the model of the process, back-calculate the controller ... PI controller Use r/ values of 0.5 and minutes 15.3 Make Nyquist plots for the process of Problem 15.1 and find the value of gain that gives the following specifications: l l l Gain margin of ... Calculate the controller gain that gives a closedloop damping coefficient of 0.3 CIJA~~EK IS: Stability Analysis of Sampled-Data Systems 537 15.8 A process controlled by a proportional digital controller...

Ngày tải lên: 24/07/2014, 07:21

... continuous analog control Computer control offers a number of advantages that outweigh its theoretical dynamic disadvantages: cost; ease of configuring and tuning control loops; ease of maintenance; ... It is defined below A sequence of impulses z.$, comes out of the impulse sampler on the input of the process Each of these impulses produces a response from the .process Consider the kth impulse ... of powers of z-t, the coefficients in front of all the terms give the values of fCllr,,, The infinite series is obtained by merely dividing the numerator of F,,, by the denominator of Fczj Z(c)...

Ngày tải lên: 24/07/2014, 07:21

... number of zeros and the number of poles of Fts, in the right half of the s plane If the process is openloop stable, none of the transfer functions in &ts, has any poles in the right half of the ... everything but the essentials A chemical engineer who is thoroughly grounded in the essence of chemical process control will be capable of understanding the features of model predictive control should ... we can tune each controller independently As we will soon see, the dynamics and stability of this multivariable closedloop process depend on the settings of all controllers Controller structures...

Ngày tải lên: 24/07/2014, 07:21

... RESPONSE OF FEEDBACK CONTROLLERS Before we give some examples of the design of feedback controllers in the frequency domain, it would be wise to show what the common P, PI, and PID controllers ... 11.13 Bode plots of controllers 11.3.1 Proportional Controller (P) The transfer function of a P controller is G cCs) = KC Substituting s = iw gives Gc(iw) = Kc (11.37) A proportional controller merely ... Proportional-Integral Controller (PI) The transfer function of a PI controller is ~‘IIAIWK I I: F;requency-I>otllaitl Analysis of Closedloop Systems G(i,,) = Kc 397 (11.38) The Bode plot of this combination of...

Ngày tải lên: 24/07/2014, 07:21

... important property of complex numbers The magnitude of the product of two complex numbers is the product of their magnitudes The argument of the product of two complex numbers is the sum of their arguments ... the size of the reactor increases The flow rate of cooling water also increases rapidly as reactor size increases The ratio of K,,, to Kmi”, which is a measure of the controllability of the system, ... used a model of the process to calculate the controller settings, but the structure of the model has not been explicitly involved in the controller design There are several alternative controller...

Ngày tải lên: 24/07/2014, 07:21

... (N - M) of 1, and the asymptotes go off at 180” Example 8.7 shows that the asymptotes go off at 60” since the order of the system is third * B Use of hIATLAB software The commercial software ... by a factor of over the firepower of the Klingon vessels, which all have the same firepower The firepower of the rest of Kirk’s fleet is on a par with that of the Klingons But these officers have ... advantages of Laplace transforms The techniques involve finding the transfer function of the openloop process, specifying the desired performance of the closedloop system (process plus controller),...

Ngày tải lên: 24/07/2014, 07:21

... controllability factor can be some measure of the “goodness” of control (integral of the squared error), the cost of the control effort, or the value of some controllability measure (such as the plant ... steady-state effects of recycles 6.2 EFFECT OF RECYCLE ON TIME CONSTANTS One of the most important effects of recycle is to slow down the response ,of the process, i.e., increase the process time constant ... The annual profit for each plant is calculated by taking the value of the onspecification products and subtracting the cost of reprocessing off-specification material, the cost of raw materials,...

Ngày tải lên: 24/07/2014, 07:21

... performance of a control system These structures include ratio control, cascade control, and override control 4.1 RATIO CONTROL As the name implies, ratio control involves keeping constant the ratio of ... type of nonlinear control can bc achieved by using nonlinear transformations of the controlled variables For example, in chemical reactor control the rate of reaction can be controlled instead of ... of adaptive control strategies in process control 4.6 VALVE POSITION (OPTIMIZING) CONTROL Shinskey [Chem Erg Prog 72(5):73, 1976; Chem Eng Prog 74(5):43, 19781 proposed the use of a type of control...

Ngày tải lên: 24/07/2014, 07:21