800xTrend activated by a trigger to log for startup period
Any idea to get the Trend logging activated by trigger in 800xA ( 5.1 or 6.0 )
Activate high sampling rate trend in process startup ( Automatically triggered by Logic )
You can program one logic in controller, with one trigger that multiply by one or by zero all data you need to register in this way all the data are 0 while you have the trigger inactive, and the real value in the case you need to register, the log is active all time.
With the historians and OPC DA framework available in 800xA you can not sample much faster than 1 second - so I don't see how to perform the "fast logging" you are searching for?
Most parameters for Basic History logs can be changed in runtime (min time, max time, period, aggregate, etc) and will have immediate effect.
However, I see no use to have a subset of Basic History logs to flip/flop between "Min Time=60s" and "Min Time=1s" just to save space between their use? The setting need human intervention and cannot be programmed/controlled from a PLC. Better having the logs permanently on "1s" and toggle the log between active and inactive state (again, this need human intervention and cannot be made from PLC).
I'm no expert on relays, but I would not be surprised if a "relay event" can be over within a few millieseconds. To sample that fast (1ms, 100us, etc) you need a dedicated logger platform with a direct connection to the hardware signals. You can not trust S800 I/O to transfer data with this resolution upwards in 800xA with OPC DA.