Run StartTimer to start the incrementation and StopTimer to stop the incrementation. The cell in question is B9 :
Public RunWhen As Double
Public Const cRunIntervalSeconds = 60
Public Const cRunWhat = "refresh"
Sub StartTimer()
RunWhen = Now + TimeSerial(0, 0, cRunIntervalSeconds)
Application.OnTime earliesttime:=RunWhen, procedure:=cRunWhat, _
schedule:=True
End Sub
Sub StopTimer()
On Error Resume Next
Application.OnTime earliesttime:=RunWhen, _
procedure:=cRunWhat, schedule:=False
End Sub
Sub refresh()
Range("B9").Value = Range("B9").Value + 100
Call StartTimer
End Sub