Siemens Module B3 ユーザーズマニュアル

 

 

 

 

 

 

 

   

 

 

 

 

T I A  Training Document 

Page 39 of 64 

  Module 

 

 
(S)FB 41 "CONT_C“ (continuous controller) is used for controlling technical processes with 
continuous input and output variables on the PLC SIMATIC S7. By means of parameter 
assignments, you can switch on or switch off subfunctions of the PID controller, and thus adjust it to 
the controlled system. 

 

 

Use: 
 
You can use the controller as PID fixed setpoint controller individually, or in multi-loop control 
systems as cascade controller, blended controller, or ratio controller. The working method is based 
on the PID algorithm of the sampling controller with analog output signal; if needed, supplemented 
with a pulse shaper step to generate pulse-width-modulated output signals for two position or three 
position controller with proportional final control elements.   
 

Description: 
 
In addition to the functions in the setpoint and actual value, the (S)FB implements a complete PID 
controller with a continuous manipulated variable output and the capability to influence the 
manipulated value manually.  

Depending on the CPU type, it can be used as FB 41 or as SFB 41.  
 
The following subfunctions exist: 
 
- 

 

Operating modes complete restart/restart 

 
The (S)FB 41 (CONT_C) has a complete restart routine that is run if the input parameter is set to 
COM_RST = TRUE. 
At startup, the integrator is set internally to the initialization value I_ITVAL. When called in a time 
interrupt level, it continues processing starting with this value.   
The other outputs are set to their default values. 
 

Error Information 

 
The error signal word RET_VAL is not used. 

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

B3 

Issued: 02/2008                                                                                                                                     Control Engineering with STEP 7