essentials of process control solution

... 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

... briefly at some of the control hardware that is currently used in process control systems: transmitters, control valves, controllers, etc Then we discuss the performance of conventional controllers ... Analog and Digital Controllers The part of the control loop with which we spend most of our time in this book is the controller The job of the controller is to compare the process signal from ... controversial subjects in process control The sizing of control valves is a good example of the engineering trade-off that must be made in designing a plant Consider the process sketched in Fig...

Ngày tải lên: 24/07/2014, 07:21

... Levels of Process Control 1.4.1 Process Control Laws / 1.4.2 Languages qf Process Control / 1.4.3 Levels of Process Control 1.5 Conclusion P A R T 20 22 24 I Time Domain Dynamics and Control ... LANGUAGES, AND LEVELS OF PROCESS CONTROL 1.4.1 Process Control Laws Several fundamental laws have been developed in the process control field as a result of many years of experience Some of these may ... knowledge not only of these traditional areas but also of the fundamentals of process control For those of us who have been part of this period of development, the attainment of parity with the...

Ngày tải lên: 24/07/2014, 07:21

... Flow diagram of proposed framework 111 Figure 6.9: ACF of process variable (y) in example 123 Figure 6.10: BI of process variable (y) in example 124 Figure 6.11: Surrogate data plot of process variable ... ends of gas concentration section Today, the operation of the FCC unit has become advanced, encompassing the use of automatic process controllers to control the key variables This is because control ... plants and (9) Mineral Processing etc However, regardless of the application, the purpose of process control is still the same and its objective is to ensure that the process is kept within certain...

Ngày tải lên: 28/11/2015, 13:34

... int aCount = 0; // number of As 12 int bCount = 0; // number of Bs 13 int cCount = 0; // number of Cs 14 int dCount = 0; // number of Ds 15 int fCount = 0; // number of Fs 16 cout

Ngày tải lên: 06/10/2013, 08:20

... Page of Tuning of a PID controller using Ziegler-Nichols Method LAB Objective: 1) To demonstrate the use of PID controller using LabVIEW 2) Finding the values of KP and TI and TD ... there are several PID controller modules We shall use the Academic PID controller The difference between different PID controllers is shown below: Page of Program: Page of Page of Conclusion: 1) ... and described in this note The PID controller encapsulates three of the most important controller structures in a single package The parallel form of a PID controller has transfer function: (...

Ngày tải lên: 27/02/2014, 03:20

... 14.4 Implementation of Control Loops 14.4.1 ON/OFF action pneumatic controller 14.4.2 ON/OFF action electrical controller 14.4.3 PID action pneumatic controller 14.4.4 PID action control circuits ... 1.2 Process Control In order to produce a product with consistently high quality, tight process control is necessary A simple-to-understand example of process control would be the supply of water ... understanding of instrumentation and process control Instrumentation and process control involve a wide range of technologies and sciences, and they are used in an unprecedented number of applications...

Ngày tải lên: 01/04/2014, 10:58

... 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

... IEC:2000 –5– INDUSTRIAL -PROCESS CONTROL VALVES – Part 6-2: Mounting details for attachment of positioners to control valves – Positioner mounting on rotary actuators Scope This part of IEC 60534 is intended ... INTERNATIONAL ELECTROTECHNICAL COMMISSION –––––––––––– INDUSTRIAL -PROCESS CONTROL VALVES – Part 6-2: Mounting details for attachment of positioners to control valves – Positioner mounting on rotary actuators ... to be in conformity with one of its standards 6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights The IEC shall...

Ngày tải lên: 04/04/2014, 11:29

... Essentials of Control Techniques and Theory 91239.indb 10/12/09 1:40:29 PM This page intentionally left blank Essentials of Control Techniques and Theory John ... xiii Section I  Essentials of Control Techniques— What You Need to Know   1  Introduction: Control in a Nutshell; History, Theory, Art, and Practice 1.1 The Origins of Control ... paper 1.1 The Origins of Control We can find early examples of control from long before the age of “technology.” To flush a toilet, it was once necessary to tip a bucket of water into the pan—and...

Ngày tải lên: 21/06/2014, 07:20

... steady state solution (after the effects of any initial transients have died away)? The solution will be a mixture of sines and cosines of 3t, which we can represent as the real part of Xe3jt The ... frequency of the input signal will of course change the gain of the response; the gain is a function of the test frequency If tests are made at a variety of frequencies, then a curve can be plotted of ... logarithm of a product is the sum of the individual logarithms If we take the logarithm of the gain of a system described by a ratio of polynomials, we are left adding and subtracting logarithms of...

Ngày tải lên: 21/06/2014, 07:20

... properties of the real system The literature is full of simulated solutions to artificial problems, but in the case of this pendulum, the same algorithms have been used by generations of students to control ... coefficient of λ3 that the coefficient of tiltrate must exceed that of v The coefficient of tilt must be greater than that of x, but must also ­ vercome o 91239.indb 118 10/12/09 1:43:39 PM Controlling ... 0.36788) = 10/12/09 1:43:25 PM 110  ◾  Essentials of Control Techniques and Theory The limit of ak for stability has now reduced below 2.4 (otherwise the product of the roots is greater than unity),...

Ngày tải lên: 21/06/2014, 07:20

... to have to deduce the rate of change of tilt instead of measuring it directly In Section 8.9 we saw that a rate signal could be generated just by a couple of lines of software, xslow = xslow + ... ◾  Essentials of Control Techniques and Theory 10.4 Complex Integration In real calculus, integration can be regarded as the inverse of differentiation If we want to evaluate the integral of ... the pole, that is the limiting value of (z – a) f(z) as z tends to a The residue can be thought of as the value of the function when the offending factor of the denominator is left out We can...

Ngày tải lên: 21/06/2014, 07:20