Option Explicit
 
Private WithEvents tmr As ApiTimer
 
Private Sub cmdStartTimer_Click()
   Dim nextHour As Date
   Dim mSeconds As Long
 
   'die nächste volle Stunde ermitteln
   nextHour = CDate(Hour(Now) & ":00")
   nextHour = DateAdd("h", 1, nextHour)
   Set tmr = New ApiTimer
   'Differenz von jetzt auf die nächste Stunde in Millsekuden
   mSeconds = DateDiff("s", Time, nextHour) * 1000
   tmr.Interval = mSeconds
   tmr.Enabled = True
 
   Debug.Print "Interval: " & mSeconds & " msec - " & mSeconds / 60000 & " min"
 
End Sub
 
 
Private Sub Form_Load()
   cmdStartTimer.Caption = "Start Timer"
End Sub
 
Private Sub tmr_Timer()
   Debug.Print "Timer-Event"
   'Stop
   tmr.Interval = 60& * 1000&
   'tmr.Interval = 2000
End Sub
 
Private Sub Form_Unload(Cancel As Integer)
   Set tmr = Nothing
End Sub