Page History

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1. Transmission connects and publishes its BIRTH
   1. The timestamp for Tag1 set at the Edge to 'now' per the Edge's system clock.
      
      
2. Tag change events occur naturally at the Edge
   1. During this time the timestamp is always set using the tag change event time at the Edge. This results in Tag1's timestamp at Engine matching that of the Edge.
      
      
3. Transmission loses connection
   1. Transmission caches a BIRTH to the history store with the timestamp for Tag1 set to 'now' per the Edge's system clock.
   2. All changes to Tag1 at the Edge are stored to the configured History Store.
   3. At this point, Engine 'stales' the tag by setting the quality to BAD_STALE and sets the timestamp of Tag1 to 'now' per the Central Gateway's system clock.
   4. The tag may or may not be changing at the Edge - Engine won't know in real time this is happening so it sets the quality of Tag1 to BAD_STALE.
      
      
4. Transmission reconnects and publishes the cached history store BIRTH
   1. The timestamp for Tag1 set at the Edge to 'now' per the Edge's system clock.
   2. The history store is flushed before any live data is published. This means that any changes to Tag1 will be stored to the history store until the flush is complete.
   3. Assuming the quality of Tag1 at the Edge is GOOD - it will be set to GOOD at Engine.
   4. If the tag value had never changed at the Edge, then you would see three events with the same value, three different timestamps, and the quality go from GOOD -> BAD_STALE -> GOOD.

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1. Transmission connects and publishes its BIRTH
   1. The timestamp for Tag1 set at the Edge to 'now' per the Edge's system clock.
      
      
2. Tag change events occur naturally at the Edge
   1. During this time the timestamp is always set using the tag change event time at the Edge. This results in Tag1's timestamp at Engine matching that of the Edge.
      
      
3. Transmission loses connection
   1. Transmission caches a BIRTH to the history store with the timestamp for Tag1 set to 'now' per the Edge's system clock.
   2. All changes to Tag1 at the Edge are stored to the configured History Store.
   3. At this point, Engine 'stales' the tag by setting the quality to BAD_STALE and sets the timestamp of Tag1 to 'now' per the Central Gateway's system clock.
   4. The tag may or may not be changing at the Edge - Engine won't know in real time this is happening so it sets the quality of Tag1 to BAD_STALE.
      
      
4. Transmission reconnects and publishes the cached history store BIRTH
   1. The timestamp for Tag1 set at the Edge to 'now' per the Edge's system clock.
   2. The history store will be flushed whilst live data is published.  This means that any changes to Tag1 will be interleaved with the historic data publishes.
   3. Assuming the quality of Tag1 at the Edge is GOOD - it will be set to GOOD at Engine.
   4. If the tag value had never changed at the Edge, then you would see three events with the same value, three different timestamps, and the quality go from GOOD -> BAD_STALE -> GOOD.

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