计时器

Public RunWhen As Double
Public Const cRunIntervalSeconds = 120 ‘ two minutes
Public Const cRunWhat = "TheSub"  ‘ the name of the procedure to run
Sub StartTimer()
    RunWhen = Now + TimeSerial(0, 0, cRunIntervalSeconds)
    Application.OnTime EarliestTime:=RunWhen, Procedure:=cRunWhat, Schedule:=True
    Range("a1") = Time
End Sub
Sub TheSub()
    StartTimer  ‘ Reschedule the procedure
End Sub
Sub StopTimer()
    On Error Resume Next
    Application.OnTime EarliestTime:=RunWhen, Procedure:=cRunWhat, Schedule:=False
End Sub