```pascal
FUNCTION "mmH2O_TO_Freq" : Real
{ S7_Optimized_Access := 'FALSE' }
AUTHOR : 'Author'
FAMILY : 'Function'
NAME : 'Name'
VERSION : 1.0
   VAR_INPUT 
      i_Head : Real;   // Request Head in mmH2O
      i_K_Pump : Real;   // Freq TO Head Pump Factor
   END_VAR

   VAR_TEMP 
      mCalc : Real;
   END_VAR


BEGIN
	
	(*  Calculates the pump frequency TO get an input head
	
	    Freq         =    Pump Frequency [Hz]
	    K_mBar       =    Freq TO Head Pump Constant
	
	    Head [ mBar] = Freq^2 * K_Pump                   *)
	
	//        Pompa INOXPA Modello ______   Motore 4 Poli 960 RPM 
	
	(* classic code: IF #i_K_Pump <> 0.0 THEN*)
	IF #i_K_Pump <> REAL#0.0 THEN
	     #mCalc := SQRT ( #i_Head / #i_K_Pump );
	END_IF;
	
	(* classic code: #mmH2O_TO_Freq := LIMIT(MN:= 0, IN:= #mCalc, MX:= 100.0) ;*)
	#mmH2O_TO_Freq := LIMIT(MN:= 0, IN:= #mCalc, MX:= REAL#100.0) ;
	
	
END_FUNCTION


```