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.
- Connect to the controller that contains the point you wish to monitor.
- Create an internal DA or DI point to use as a monitoring point. (Set 0 as normal and 1 as alarm)
- Add a Calculation extension to this point with this Calculation: OLD(P0) [where P0 is the point you wish to monitor going old]
- 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