看来节奏难带啊... ...

就是用  “西山炮台” 说的方法，自己做减法了。

#iTemp := RD_SYS_T(OUT=>#ACTUAL_TIME);   //读取当前系统时间

IF    #ACTUAL_TIME.YEAR=#LAST_TIME.YEAR

  AND #ACTUAL_TIME.MONTH=#LAST_TIME.MONTH

  AND #ACTUAL_TIME.DAY=#LAST_TIME.DAY

  AND #ACTUAL_TIME.HOUR=#LAST_TIME.HOUR

  AND #ACTUAL_TIME.MINUTE=#LAST_TIME.MINUTE

THEN

  #rCycleTime := LREAL_TO_REAL(#ACTUAL_TIME.SECOND-#LAST_TIME.SECOND+LReal#1.0E-9*(UDINT_TO_LREAL(#ACTUAL_TIME.NANOSECOND)-UDINT_TO_LREAL(#LAST_TIME.NANOSECOND)));

END_IF;

#rDeltaTime := 1.0E-3*DINT_TO_REAL(TIME_TO_DINT(T_DIFF(IN1:=#ACTUAL_TIME, IN2:=#LAST_TIME)));

#LAST_TIME := #ACTUAL_TIME;  //为下一次调用做准备

Test.rar

测试程序在附件内。