 Home
 Products
 Integration
 Tutorial
 Barcode FAQ
 Purchase
 Company
barcode reader using c#.net CONTROL in Software
CONTROL Decoding ANSI/AIM Code 128 In None Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications. Code 128 Creator In None Using Barcode generation for Software Control to generate, create Code 128 Code Set B image in Software applications. SYSTEM
Code 128A Reader In None Using Barcode scanner for Software Control to read, scan read, scan image in Software applications. Code128 Drawer In C# Using Barcode generator for VS .NET Control to generate, create Code 128 Code Set C image in VS .NET applications. DESIGN
Creating Code128 In .NET Framework Using Barcode encoder for ASP.NET Control to generate, create Code128 image in ASP.NET applications. Paint Code 128A In Visual Studio .NET Using Barcode printer for VS .NET Control to generate, create ANSI/AIM Code 128 image in .NET framework applications. FREQUENCY
Code 128 Code Set B Maker In VB.NET Using Barcode drawer for VS .NET Control to generate, create Code 128C image in .NET framework applications. Creating USS Code 39 In None Using Barcode creator for Software Control to generate, create USS Code 39 image in Software applications. RESPONSE
ECC200 Printer In None Using Barcode printer for Software Control to generate, create DataMatrix image in Software applications. Generating EAN 13 In None Using Barcode printer for Software Control to generate, create EAN 13 image in Software applications. criteria. Fortunately, for this case and others there are simple rules for directly establishing values of the control parameters that usually give satisfactory gain and phase margins. These are the ZieglerNichols rules, which we develop in the next section. USS128 Creator In None Using Barcode printer for Software Control to generate, create UCC.EAN  128 image in Software applications. Paint Barcode In None Using Barcode printer for Software Control to generate, create bar code image in Software applications. ZieglerNichols
European Article Number 8 Creation In None Using Barcode generator for Software Control to generate, create EAN / UCC  8 image in Software applications. Printing Bar Code In .NET Using Barcode generator for ASP.NET Control to generate, create bar code image in ASP.NET applications. Controller
EAN / UCC  13 Generator In ObjectiveC Using Barcode printer for iPhone Control to generate, create EAN 13 image in iPhone applications. Draw Code 128B In Java Using Barcode generator for Java Control to generate, create Code 128 image in Java applications. Settings
Bar Code Creation In ObjectiveC Using Barcode generation for iPhone Control to generate, create barcode image in iPhone applications. Bar Code Maker In Java Using Barcode creator for Eclipse BIRT Control to generate, create barcode image in BIRT reports applications. Consider selection of a controller G, for the general control system of Fig. 17.5. We first plot the Bode diagram for the final control element, the process, and the measuring element in series, GiG2H(ju). It should be emphasized that the controller is omitted from this plot. Suppose the diagram appears as in Fig. 17.6. As noted on the figure, the crossover frequency for these three components in . . senes is o,,. At the crossover frequency, the overall gain is A, as indicated. According to the Bode criterion, then, the gain of a proportional controller which would cause the system of Fig. 17.5 to be on the verge of instability is l/A. We define this quantity to be the ultimate gain K,. Thus Code 128 Code Set B Encoder In ObjectiveC Using Barcode generator for iPhone Control to generate, create Code 128C image in iPhone applications. Scan UPCA In Visual Basic .NET Using Barcode recognizer for .NET framework Control to read, scan read, scan image in .NET applications. K, = A' (17.3) The ultimate period P, is defined as the period of the sustained cycling that would occur if a proportional controller with gain K, were used. From the discussion of Fig. 17.3, we know this to be p, = E
time/cycle
(17.3a) The factor of 2~ appears, so that P, will be in units of time per cycle rather than time per radian. It should be emphasized that K, and P, are easily determined from the Bode diagram of Fig. 17.6. The ZieglerNichols settings for controllers are determined directly from K, and P, according to the rules summarized in Table 17.1. Unfortunately, specifications of K, and ro for PD control cannot be made using only K, and P,. In general, the values 0.6K, and PUB, which correspond to the limiting case of no integral action in a threemode controller, are too conservative. That is, the TABLE 17.1
ZieglerNichols Controller Settings
ljpe of control Proportional Proportionalintegral (PI) (PID) G,(s) KC KC 71 7D
OJK, 0.45K,, p,, i
Proportionalintegralderivative
FREQUENCY
RESPONSE
resulting system will be too stable. There exist methods for this case which am in principle no more difficult to use than the ZieglerNichols rules. One of these is selection of ~0 for maximum K, at 30 phase margi , which was discussed above. Another method, which utilizes the step response L d avoids trial and error, is presented in Chap. 19. The reasoning behind the ZieglerNichols selection of values of K, is relatively clear. In the case of proportional control only, a gain margin of 2 is established. The addition of integral action introduces more phase lag at all frequencies (see Fig. 16.10); hence a lower value of Kc is required to maintain roughly the same gain margin. Adding derivative action introduces phase lead. Hence, more gain may be tolerated. This was demonstrated in Example 17.2. However, by and large the ZieglerNichols settings am based on experience with typical processes and should be regarded as first estimates. Example 17.3. Using the ZieglerNichols rules, determine K, and ~1 for the control system shown in Fig. 17.10. For this problem, the computation will be done without plotting a Bode diagram; however, the reader may wish to do the problem with such a diagram. We first obtain the crossover frequency by applying the Bode stability criterion: 180 =  tan (o)  57.3(1.0;)(0) The value 57.3 converts radians to degrees. Solving this equation by trial and error gives for the crossover frequency, wCO = 2 rad/min. The amplitude ratio (AR) at the crossover frequency for the open loop can be written A R = where we have used Eq. (16.16) for the firstorder system and the fact that the amplitude ratio for a transport lag is one. According to the Bode criterion, the AR is 1.0 at the crossover frequency when the system is on the verge of instability. Inserting AR = 1 into the above equation and solving for K, gives K,, = 2.24. From the ZieglerNichols rules of Table 17.1, we obtain K, = 0.45K,, = (0.45)(2.24) = 1.01 and 71 = PJ1.2 = [21rlw,,]/1.2 = [21r/2]/1.2 = 2.62 min. b :

