Siemens Module B3 ユーザーズマニュアル

 

 

 

 

 

 

 

   

 

 

 

 

T I A  Training Document 

Page 54 of 64 

  Module 

 
5. SETTING CONTROLLED SYSTEMS 
 

 

Below, setting controlled systems is discussed, using a PT2 system as an example. 

The basis for the methods according to Ziegler-Nichols and according to Chien, Hrones and 

Reswick is the T

u

-T

g

 approximation.  With it, the parameters following parameters transfer coefficient 

of the system K

S

, delay T

u

 und transition time T

g

 can be determined from the system step response. 

The rules for controller adjustment that are described below were found experimentally, by using 

analog computer simulations.  

P-T

N

 systems can be described with sufficient accuracy with a so-called T

u

-T

g

 approximation; that 

means, through approximation by means of a P-T

1

-T

L

 system.  

Starting point is the system step response with the input step height K. The necessary parameters: 

transfer coefficient of the system K

S

, delay T

u

 and transition time T

g

 are ascertained as shown in the 

figure below. 

This requires measuring the transition function up to the stationary upper range value (K*Ks), so that 

the transfer coefficient for system K

S, 

 required for the calculation, can be determined. 

The essential advantage of these methods is that the approximation can also be used if the system 

can not be described analytically. 

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Preface    Fundamentals     Discontinuous Action Controller     Controller Block (S)FB41     Setting the System     Appendix 

 

Wendepunkt 

K*K

S

 

T

g

T

u

 

Turning Point 

t/sec 

B3 

Issued: 02/2008                                                                                                                                     Control Engineering with STEP 7