Detailed Description   
2.12 Block descriptions 
  PLC Basic Program Solution Line (P3 sl) 
2-176  Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0 
2.12.18  FC 12: AUXFU call interface for user with auxiliary functions 
Description of functions 
FC AUXFU is generally called on an event-driven basis in the basic program if the channel 
transferred in the input parameter contains new auxiliary functions. The PLC user can extend 
FC AUXFU with program instructions for processing his auxiliary function to avoid cyclic 
polling of the channel DBs. This mechanism permits auxiliary functions to be processed on a 
job-driven basis. FC AUXFU is supplied as a compiled empty block in the basic program. In 
this case, the basic program supplies parameter "Chan" with the channel number. The PLC 
user knows which channel has new auxiliary functions available. The new auxiliary functions 
can be determined by the auxiliary-function change signals in the channel concerned. 
Declaration 
 
FUNCTION FC 12: VOID  //Event control of auxiliary functions 
VAR_INPUT 
 Chan:  BYTE ; 
END_VAR 
BEGIN 
 BE; 
END_FUNCTION 
Explanation of formal parameters 
The table below lists all formal parameters of the AUXFU function: 
 
Signal  Type  Type  Value range  Remarks 
Chan  I  Byte  0 to 9  No. of NC channel -1