1. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved

2. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved OBJECTIVES: By the end of this chapter, you should:- Understand the functional layout for a single control loop. Be able to explain the meaning of the terms controlled variable, disturbance, manipulated variable, and etc. Be able to construct a single loop Signal Flow Diagram / Signal Block Diagram. Appreciate the mathematical structure of a single control loop.

3. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved Represent the relationship between signal and instruments for the whole system - Formalize control system as “Pictures”. - Have mathematical models to system components. - Components can be combined to produce an overall mathematical description of systems. - Interaction between elements is well defined. Why we need Signal Flow/Block Diagram? DEFINITION

4. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved MEASURING ELEMENT Set Point CONTROL LAW Final control Element PROCESS X y z we CONTROLLER SIGNAL BLOCK DIAGRAM

5. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved MEASURING ELEMENT Set Point CONTROL LAW FCE PROCESS x y z we CONTROLLER e or Xd – error/control difference/deviation - the difference between set point and measured value (controlled variable) x d = w-x or e =SP-PV w – set point/command variable - the value that we desired y – correcting/manipulated variable – is a controller output or a value has a direct effect to the control element z – disturbances/unwanted variable - the unwanted variable that affect the process x – controlled/measured variable - the system/variable that we going to controlled ANNOTATIONS

6. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved Command Variable (w) / Set Point (SP) –The required value of the process variable may be set by the operator or by the output of another controller (cascaded) Control difference (Xd) / Error (E) –Measure how far the process variable is from the set point –Defined as SP-PV Controlled Variable (x) / Process Variable (PV) –The measured value of the variable to be controlled Correcting Variable (y) / Manipulated Variable (MV) –The variable that is adjusted to correct any error Disturbance Variable (z) –The variable that drive the controlled variable away from their desired or setpoint conditions TERMS & DEFINITIONS

7. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved DIN JIS,ANSI, BS Controlled Variable xPV Set Variable wSV Manipulated Variable yMV Disturbance Variable zD ANNOTATIONS

8. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved

9. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved RECTANGLE BLOCK

10. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved G xy G x1 y x2 x3 x4 RECTANGLE BLOCK y = G.x y = ? (Not allowed) Indicates Function

11. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved z = ? x y a b c d e = ? Two input: z = ? SUMMING POINT Three or more : e = ? Indicates Combination of Signal

12. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved X1 BRANCH POINT Division of a signal to give two or more paths without modification

13. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved INTERACTION BETWEEN ELEMENT

14. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved

15. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved MANIPULATION OF BLOCK DIAGRAM A(s) X(s) B(s) Y(s) Z(s) In using block diagrams to analyze control problems it is important to be able to convert from one form to another. A(s)B(s) X(s) Z(s) A(s) X(s) B(s) Z(s) + + A(s) + B(s) X(s) Z(s) A(s) X(s) Y(s) Z(s)+ - A(s) X(s) Y(s) Z(s) + - A(s) X(s) Z(s)+ - A(s) 1+A(s) X(s) Z(s)

16. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved MANIPULATION OF BLOCK DIAGRAM

17. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved MANIPULATION OF BLOCK DIAGRAM

18. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved MANIPULATION OF BLOCK DIAGRAM

19. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved MANIPULATION OF BLOCK DIAGRAM

20. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved MANIPULATION OF BLOCK DIAGRAM

21. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved CONCLUSION

22. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved - Setpoint : Desired Speed - Controlled Variable: Actual Speed - Measuring Element: Tachometer measurement + Noise - Signal Type: Voltage - Disturbance: Variation of Load Torque 1. DC Motor Speed Control W x EXAMPLE OF C/L CONTROL

23. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved 2. Aircraft Autopilot -Goal: Keep aircraft on desired path -Disturbance: Wind,air density and etc -Feedback: To reject Disturbance EXAMPLE OF C/L CONTROL

24. Industrial Electronic Department Copyright of German Malaysian Institute. All rights reserved THERMOSTAT Set Point CONTROL LAW VALVE HOME HEATING X y z we TEMPERATURE CONTROLLER Home Heating System