Event frames start trigger on trigger condition change
I would like to be able to define start trigger that fires a e new event frames only if the start condition changes. I mean:
- Start trigger: 'Equip Status' = "ON"
- End trigger: 'Equip rpm' >= 1000
I would like that the event start is triggered only if the 'Equip Status' changes from OFF to ON (discarding Bad Values).
This is because when the event ends, the Equip Status is sitll ON and there are lots of false generated events.
In response to Stephen Kwan, "Hi Nicola, Have you looked at using the..."
HasValueChanged wouldn't help with Bad Values, as going to Bad and then back to ON would trigger a new EF.
Furthermore it would not help with analog tags I suppose.
Have you looked at using the builtin function "HasValueChanged"?
In response to Brent Bregenzer, "Hi, Nicola. Would a start trigger like '..."
that is how I am doing it now, but it gives me some problems with bad values.
Furthermore that doesn't solve the problem when I work with analog signals...
For example when the start trigger is 'equip rpm' >3600.
I can still make it work with
'equip rpm' >3600 And TagVal('equip rpm', '*-15m')<3600 but it leads to trial and error process.
Brent Bregenzer commented
Would a start trigger like 'Status' = "ON" AND PrevVal('Status','*') = "OFF" work for your use case? Please let us know what you think.