SetTimer(ELAPSE, CALLBACK)

The SetTimer() function starts an asynchronous timer, which invokes the CALLBACK every time ELAPSE milliseconds have expired. Calling SetTimer() with ELAPSE set to 0 stops the timer for this specific CALLBACK. If CALLBACK is omitted, it will default to Timer().

The ELAPSE parameter can also be specified in "hh:mm:ss.xxxx" format. Examples are:

  :15       => 15 seconds
  1:30      => 1 hour, 30 minutes
  4:30:15   => 4 hours, 30 minutes, 15 seconds
  2.500     => 2 seconds, 500 milliseconds

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 SetTimer ( 1800000, \&ip )  # 1800 seconds x 1000 for millisecs
 #or possibly 
 SetTimer ( 0:30, \&ip);