Control Engineering - A guide for beginners - Chapter 6 doc

... transfer from automatic to manual mode, where the manipulating variable remains at its current value, and can then be changed manually. In case of a broken probe, caused, for example, by a cable fault ... invaluable for trials and test runs, when the manipulating variable has to be operated in manual mode, i.e. without automatic control. They can be integrated in the controller or a...

Ngày tải lên: 07/08/2014, 15:20

... the manipulating variable MV. There are a number of ways to carry out this task: me- chanical, pneumatic, electrical, mathematical. The mechanical controller, for example, alters a sig- nal through ... this way leads to a loss of informa- tion about the measured signal. Binary signals In their simplest form the signals can only have two states, and are therefore called binary signals....

Ngày tải lên: 07/08/2014, 15:20

... T g Temperature small electrically-heated oven large electrically-heated furnace large gas-fired reheating furnace autoclave high-pressure autoclave injection molding machine extruder packaging machine ... of a change in manipu- lating variable is only reproduced in the process variable after the dead time has elapsed. If the change in manipulating variable was too large, there is a time...

Ngày tải lên: 07/08/2014, 15:20

... manipulating variable slowly increased by hand, allowing adequate time after the change for the end temperature to be reached. A certain value of manipulating variable will be de- termined, for ... working point A P controller only produces a manipulating variable when there is a control deviation, as we al- ready know from the controller equation. This means that the manipulati...

Ngày tải lên: 07/08/2014, 15:20

... error is also used as a measure of control quality (see Fig. 46) . Linear control area (linear optimum): [A] min = A 1 - A 2 + A 3 Magnitude control area (magnitude optimum): [A] min = | A 1 ... distur- bances of the characteristics in a control loop normally has to be accepted as given, good control quality can only be achieved by a suitable choice of con...

Ngày tải lên: 07/08/2014, 15:20

... a modulating controller. It forms a type of cascade structure (see Chapter 6. 6), and consists of a continuous controller and a subordi- nate actuating controller (Fig. 63 ). Fig. 63 : The actuating ... manipulating variable on the regulating valve. The actuating controller operates the ac- tuator via two switching outputs, and receives an actuator retransmission signal (usuall...

Ngày tải lên: 07/08/2014, 15:20

... such as temperature, pressure or voltage has to take up a specified value, and maintain it as accurately as possible. A simple example is a furnace whose temperature has to be maintained constant. ... output variables. 1.9 Main areas of control engineering Today, control engineering has applications in almost every area of technology. In Chapter 1.1 we have already seen that t...

Ngày tải lên: 13/12/2013, 00:14

... with a Gmail account. To create a Gmail address, go to http://mail.google.com. Gmail and Other Email If you like, Gmail can check other email addresses, and it can also forward email to another address. ... looks. The advantage of creating a website manually is the degree of customization you can have, and the disadvantage is the amount of work it can take to create and maintain, and th...

Ngày tải lên: 29/05/2014, 15:45

... and retrain people mean the need to teach and learn at a distance will escalate. Some of the main benefits of online learn- ing (a form of distance learning) are flexibility (people can learn at ... country and requiring learners to sit in a classroom for a set number of hours. • Improved control and standardization. In today’s interna- tional business climate, many organizations hav...

Ngày tải lên: 03/06/2014, 02:04

... station for a bulletin telling how to use formalin, as well as for information regarding other potato diseases. Give the treatment a fair trial in a portion of your field this year and watch carefully ... may better understand our apple and potato rots, as well as other plant diseases. If you cut a lemon and let it stand for a day or two, there will probably appear a blue mo...

Ngày tải lên: 02/07/2014, 05:20