Lesson 3

Information systems in control engineering

1. An information system turns collected data into meaning­ful information. Business, industry, and the military are mechanizing important information systems as fast as the communications and computer arts permit. The object of this mechanization is better information about critical operating conditions in a shorter time. And when informa­tion systems become so fast that the information can be considered «current», automatic control is feasible. Thus the information system enters the control system and control engineering.

2. Four principal functions are recognizable in informa­tion systems: data gathering, data transmission, data pro­cessing, and information presentation. The first and last are input and output functions for the information system. The transmission and processing functions may appear anywhere in the system in any order. Each of these func­tions can be mechanized in whole or in part by many tech­niques and many equipments already available.

3. Mechanized information systems have already reached the level of automatic control: in business for inventory control and automatic customer billing, in industry for control of machine-tools, unit operations and processes, and even whole production lines and operating departments; and in military operations for missile guidance and checkout defence warning, and logistics systems. There are many other examples.

4. But the much larger number of off-line applications of information systems must also concern control engineers. First, because an information system is a dynamic system and its dynamics must be made compatible with the dy­namics of the system in which it operates. Second, open-loop applications often suggest solutions for the closed-loop. And third, the end purpose of any information system is control in some sense, even if only indirect.

5. The information system fits into the control system so that its addition does not change the control system. How­ever, there is a new view of the general control system which undoubtedly should be taken by the engineers of systems that include extensive information handling.

6. The new concept is that any control system can he con­sidered as a measuring system plus an information system plus an actuating system. This view may also prove useful to control theorists for analysis of even simple systems. In this concept the information system is the decision­ maker or brains of the control system. It can include means for calculating known or probable measurements errors, and if sophisticated enough, can even make up for inade­quacies in accuracy or speed of the actuating system.

Exercise1. Find the synonyms in the text to the following words:

1. acceptable (2) 5. transform (1)

2. suppose (4) 6. main (2)

3. complex (6) 7.method (2) .

4. precision (6) 8. goal (4)

9. gather (1).

Exercise 2. Give the Ukrainian equivalents to the following words and word- combinations:

1. critical operation conditions;

2. mechanizing important information systems;

3. collected data;

4. data transmission;

5. information presentation;

6. anywhere in any order;

7. missile guidance.

Exercise 3. Say if the statements are true or false.

1. An information system makes data useful information.

2. Information systems are on the level of automatic control.

3. Data gathering and data transmission are input and output functions.

4. An information system changes the control system greatly.

5. The new concept is that any control system can be regarded as an actuating system.

Exercise 4. Complete the sentences choosing the right variant.

1. The object of this mechanization is…

a). automatic control;

b). better information;

c). collected data.

2. Data gathering and information presentation are…

a). I/O functions;

b). processing functions;

c). control functions.

3. Off-line applications of information systems must concern…

a). control theorists;

b). decision- makers;

c). control engineers.

4. In this concept the information system is … of this system.

a). “hands’’;

b). “brains’’;

c). “heart”.

5. Mechanized information systems are used in…

a). business and industry, military operations;

b). business, management, marketing;

c). industry, agriculture, military operations.

Exercise 5. Answer the following questions:

1. What are the main functions in the information systems?

2. What are the applications of the information systems?

3 .Why does the information system enter the control system and control engineering?

4. How can every function in the information system be mechanized?

5. What does a new concept comprise?

Exercise 6. Explain the term ”current” information.

Exercise 7. Define the object of mechanization.

Exercise 8. Explain why off- line applications of the information systems concern control engineers.

Exercise 9. Prove that the information system is the ”brains” of the control system.

Exercise 10. Discuss the text according to the points:

1. Applications of the information systems.

2. Principal functions in the information systems.

3. New concept of the general control system.

Exercise 11. Translate in writing the last passage of the text (6).

Notes:

1. customer billing - обробка рахунків покупців;

2. off - line applications - невиробничі галузі застосування;

3. feasible – придатний;

4. inventory control- облік матеріальних цінностей;

5. missile guidance – управління ракетами;

6. checkout defense warning – відбій бойової тривоги;

7. compatible – сумісний;

8. open / close loop operations – замкнуті (незамкнуті) цикли операцій.