Good point.
The "Old/Legacy/Data/IA Series" Historian (did any program every have so
many names?) uses the OM API. The OM API has the ability to set the update
scan rate on the list. The Historian uses this feature. However, the rate is
adjustable only between 0.5 seconds in 10s in 0.5 second in
Message text written by "Foxboro DCS Mail List"
>To generate a change in the historian, set the change delta to a very,
very small number,
but not zero (0). A zero change delta will result in a new value in the
historian every 0.5 seconds.<
Alex,
Will a 0.0 deadband make to historian record a new
The problem here is if the change delta is too small you don't get any
value. Still, you could set it to be very, very small, but not zero and get
what you want.
My concern is that normally this request comes when the value to be recorded
is used for validation in a plant, e.g., FDA or EPA, and t
AIM*Historian has event triggered data.
The "Old/Legacy/IA Series" Historian is strictly change driven. Changes can
be generated based on:
1) Delta violations
2) Status Bit changes
So, I think your options are:
1) Use a variable with a known "ignore me" value and the "good" val
Hi David,
You might have the value you want to record copied to a second block -
like a real or calc ROxx, and then have that second calue stored by the
historian. That way your second value only changes when your counter logic
tells it to, and the historian never "sees" the original value cha
Hello all,
I was wondering if there is a good way to do event triggered data
collection in the legacy (Informix) historian. Ideally I would like to
place a value in the historian only when a counter increments. Is there a
way to do this at the historian configuration level, or do I need to w
