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Triggering an alarm or message if a point goes old in I/NET


Triggering an alarm or message if a point goes old in I/NET




Need to track or actively monitor points that are frequently found with an Old flag.


  1. Connect to the controller that contains the point you wish to monitor.
  2. Create an internal DA or DI point to use as a monitoring point. (Set 0 as normal and 1 as alarm)
  3. Add a Calculation extension to this point with this Calculation:  OLD(P0)  [where P0 is the point you wish to monitor going old]
  4. If you wish to use one point to monitor several points that may go old, simply use the OR symbol which is " | ".  The expression will look like this: OLD(P0)|OLD(P1)|OLD(P2)...


  • Whenever the monitored point goes old, your internal monitoring point will change to a value of 1.
  • Remember that the calculation only runs once every scan interval so a longer scan interval will delay your results.

For further Indirect Point "Old Data" Filtering Techniques read Lessons Learned #5488

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