VBA Macro On Timer style to run code every set number of seconds, i.e. 120 seconds

When the workbook first opens, execute this code:

alertTime = Now + TimeValue("00:02:00")
Application.OnTime alertTime, "EventMacro"

Then just have a macro in the workbook called "EventMacro" that will repeat it.

Public Sub EventMacro()
    '... Execute your actions here'
    alertTime = Now + TimeValue("00:02:00")
    Application.OnTime alertTime, "EventMacro"
End Sub

Yes, you can use Application.OnTime for this and then put it in a loop. It's sort of like an alarm clock where you keep hittig the snooze button for when you want it to ring again. The following updates Cell A1 every three seconds with the time.

Dim TimerActive As Boolean
Sub StartTimer()
    Start_Timer
End Sub

Private Sub Start_Timer()
    TimerActive = True
    Application.OnTime Now() + TimeValue("00:00:03"), "Timer"
End Sub

Private Sub Stop_Timer()
    TimerActive = False
End Sub

Private Sub Timer()
    If TimerActive Then
        ActiveSheet.Cells(1, 1).Value = Time
        Application.OnTime Now() + TimeValue("00:00:03"), "Timer"
    End If
End Sub

You can put the StartTimer procedure in your Auto_Open event and change what is done in the Timer proceedure (right now it is just updating the time in A1 with ActiveSheet.Cells(1, 1).Value = Time).

Note: you'll want the code (besides StartTimer) in a module, not a worksheet module. If you have it in a worksheet module, the code requires slight modification.

In Workbook events:

Private Sub Workbook_Open()
    RunEveryTwoMinutes
End Sub

In a module:

Sub RunEveryTwoMinutes()
    //Add code here for whatever you want to happen
    Application.OnTime Now + TimeValue("00:02:00"), "RunEveryTwoMinutes"
End Sub

If you only want the first piece of code to execute after the workbook opens then just add a delay of 2 minutes into the Workbook_Open event