Siemens Module B3 ユーザーズマニュアル

 

 

 

 

 

 

 

   

 

 

 

 

T I A  Training Document 

Page 17 of 64 

  Module 

 

The controlled variable continues to grow after a fault, without aiming for the high range value. 

 
 
 
 
 
 
 
 
 
 

Example: Level Control  

In the case of a container with a drain whose inflow volume stream and outflow volume stream are 

the same, a constant level is the result. If the flow rate of the inflow or the outflow changes, the liquid 

level rises or falls.  The larger the difference between inflow and outflow, the faster does the level 

change.  

The example shows that in practice, the integral action usually has limits. The controlled variable 

rises or fills up only so long until it has reached a limit that is contingent on the system:  the container 

overflows or empties, the pressure reaches the plant maximum or minimum, etc.. 

The figure shows the trend of an I-system when there is an abrupt change of the input variable, as 

well as the block diagram derived from it. 

 

 

 

 

Block Diagram

 

 

 

 

 

 

 

If the step function at the input changes into any function xe(t), the following happens: 

 
 

integrating controlled system 

 integral coefficient of the controlled system 

 
 
 
 

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

B3 

Issued: 02/2008                                                                                                                                     Control Engineering with STEP 7