FUNCTION "UnixTimeStamp" : String
{ S7_Optimized_Access := 'FALSE' }
VERSION : 0.1
   VAR_TEMP 
      Leapyears : Int;
      Days_from_1970 : DInt;
      days_from_BeginOfYear : Array[1..12] of Int;
      l_unixtime : DInt;
      sfc1_ret_val : Int;
      CDT_systemtime : Date_And_Time;
      systemtime AT CDT_systemtime : Struct
         Year_CDT : Byte;
         Month_CDT : Byte;
         Day_CDT : Byte;
         Hour_CDT : Byte;
         Minute_CDT : Byte;
         Second_CDT : Byte;
         MSec : Word;
      END_STRUCT;
      Year : Int;
      Month : Int;
      Day : Int;
      Hour : Int;
      Minute : Int;
      Second : Int;
      Msecs : Int;
   END_VAR


BEGIN
	// Convert system time to unix time
	// (seconds until 1970-01-01 00:00)
	
	
	
	
	
	#Leapyears := 0;
	#Days_from_1970 := 0;
	
	// days of current month without leap day
	
	#days_from_BeginOfYear[1] := 0;
	#days_from_BeginOfYear[2] := 31;
	#days_from_BeginOfYear[3] := 59;
	#days_from_BeginOfYear[4] := 90;
	#days_from_BeginOfYear[5] := 120;
	#days_from_BeginOfYear[6] := 151;
	#days_from_BeginOfYear[7] := 181;
	#days_from_BeginOfYear[8] := 212;
	#days_from_BeginOfYear[9] := 243;
	#days_from_BeginOfYear[10] := 273;
	#days_from_BeginOfYear[11] := 304;
	#days_from_BeginOfYear[12] := 334;
	
	
	// read system time
	#sfc1_ret_val := RD_SYS_T(#CDT_systemtime);
	#Year := BCD16_TO_INT(#systemtime.Year_CDT) + 2000;
	#Month := BCD16_TO_INT(#systemtime.Month_CDT);
	#Day := BCD16_TO_INT(#systemtime.Day_CDT);
	#Hour := BCD16_TO_INT(#systemtime.Hour_CDT);
	#Minute := BCD16_TO_INT(#systemtime.Minute_CDT);
	#Second := BCD16_TO_INT(#systemtime.Second_CDT);
	
	#Msecs := BCD16_TO_INT(SHR(IN := #systemtime.MSec, N := 4));
	
	// sum of leap years since 1979 (without current leap year)
	#Leapyears := ((#Year - 1) - 1968) / 4
	- ((#Year - 1) - 1900) / 100
	+ ((#Year - 1) - 1600) / 400;
	
	
	#Days_from_1970 := (#Year - 1970) * 365 + #Leapyears
	+ #days_from_BeginOfYear[#Month] + #Day - 1;
	
	IF ((#Month > 2) AND ((#Year MOD 4 = 0) AND ((#Year MOD 100 <> 0) OR (#Year MOD 400 = 0)))) THEN
	    #Days_from_1970 := #Days_from_1970 + 1; // + leap day, if year is leap year
	END_IF;
	
	// OUTPUT in s
	#l_unixtime := #Second + 60 * (#Minute + 60 * (#Hour + 24 * #Days_from_1970));
	
	
	// if error return 0
	IF #sfc1_ret_val <> 0 THEN
	    #UnixTimeStamp := '';
	ELSE
	    
	    CASE #Msecs OF
	        0..9:
	            #UnixTimeStamp := CONCAT(IN1 := DELETE(IN := DINT_TO_STRING(#l_unixtime), L := 1, P := 1),
	                                     IN2 := DELETE(IN := INT_TO_STRING(#Msecs), L := 1, P := 1), IN3 := '00000000');
	        10..99:
	            #UnixTimeStamp := CONCAT(IN1 := DELETE(IN := DINT_TO_STRING(#l_unixtime), L := 1, P := 1),
	                                     IN2 := DELETE(IN := INT_TO_STRING(#Msecs), L := 1, P := 1), IN3 := '0000000');
	        100..999:
	            #UnixTimeStamp := CONCAT(IN1 := DELETE(IN := DINT_TO_STRING(#l_unixtime), L := 1, P := 1),
	                                     IN2 := DELETE(IN := INT_TO_STRING(#Msecs), L := 1, P := 1), IN3 := '000000');
	            
	        ELSE
	            #UnixTimeStamp := '';
	    END_CASE;
	        
	        
	   
	END_IF;
	
	
	
END_FUNCTION