//GET THE SYSTEM CLOCK
CALL "READ_CLK"
RET_VAL:=#STATUS1
CDT :=#SYSTEM_DATE_AND_TIME
//MOVE SYSTEM CLOCK INFO INTO DB499
CALL "Block Move"
SRCBLK :=#SYSTEM_DATE_AND_TIME
RET_VAL:=#STATUS1
DSTBLK :="DATE AND TIME BCD".TimeStamp
//CONVERT YEAR VALUE FROM BCD TO INTEGER AND CONVERT TO ACTUAL YEAR
L "DATE AND TIME BCD".TimeStamp.Year
BTI
T "DATE AND TIME INT".DateYear
L 2000
+I
T "DATE AND TIME INT".YearActual
//CONVERT MONTH VALUE FROM BCD TO INTEGER
L "DATE AND TIME BCD".TimeStamp.Month
BTI
T "DATE AND TIME INT".DateMonth
//CONVERT DAY VALUE FROM BCD TO INTEGER
L "DATE AND TIME BCD".TimeStamp.Day
BTI
T "DATE AND TIME INT".DateDay
//CONVERT HOUR VALUE FROM BCD TO INTEGER
L "DATE AND TIME BCD".TimeStamp.Hour
BTI
T "DATE AND TIME INT".DateHour
//CONVERT MINUTE VALUE FROM BCD TO INTEGER
L "DATE AND TIME BCD".TimeStamp.Minute
BTI
T "DATE AND TIME INT".DateMinute
//CONVERT SECOND VALUE FROM BCD TO INTEGER
L "DATE AND TIME BCD".TimeStamp.Second
BTI
T "DATE AND TIME INT".DateSecond
帮忙注释一下这段S7-300西门子PLC程序,谢谢!