FUNCTION_BLOCK GETCRC16
VAR_EXTERNAL
  VALCRC : array[0..100] of byte;
END_VAR

VAR_INPUT
   CRC_ADR :dword;
   CRC_LEN :word;
END_VAR

VAR_OUTPUT
   CRC16H :byte; 
   CRC16L :byte;
END_VAR

VAR
(*CRC计算用定义*)
   CRC16Lo,CRC16Hi : Byte;     
   CL,CH : Byte;		
   SaveHi,SaveLo : Byte;
   Flag: Int;
   	i : int;
	j : int;
	k : int;
(*	MemToVar : AdvMemToVar;
	VarToMem : AdvVarToMem;
*)
END_VAR
  (*MemToVar(EN :=true , DW_MEM_ADDR :=CRC_ADR , W_MEM_LEN :=CRC_LEN , STR_FILENAME :='OPCDA1' , STR_VARNAME :='VALCRC' );*)
      CRC16Lo := 255;
	  CRC16Hi := 255;
	  CL := 1;
	  CH := 160;
  
	  For i := 0 To (word_to_int(CRC_LEN)-1) by 1 do
	    CRC16Lo := CRC16Lo Xor VALCRC[i]; 
	    For Flag := 0 To 7 by 1 do
	      SaveHi := CRC16Hi;
	      SaveLo := CRC16Lo;
	      CRC16Hi := shr(CRC16Hi,1);            
	      CRC16Lo := shr(CRC16Lo,1);
	            
		      If ((SaveHi And 1) = 1) Then 
		        CRC16Lo := CRC16Lo Or 128;      
		      End_If;                           
		      If ((SaveLo And 1) = 1) Then 
		        CRC16Hi := CRC16Hi Xor CH;
		        CRC16Lo := CRC16Lo Xor CL;
		      End_If;
	     end_for;
	 
	   end_for;
   
	 CRC16H:=CRC16Lo;
	 CRC16L:=CRC16Hi; 








END_FUNCTION_BLOCK