update rate -9000ms
When I changed the update rate of some object at the control connection aspect in the control structure,
default value was -9000 ms. I want to know why default value was -9000 and what this mean?
inform : 800xA 6.03 with AC450
Voted best answer
9 sec. update is set by default, since RTA board supports 9sec, 3sec or 1sec updates.
Update rate shall be kept as slow as possible to prevent MB300 & AC450 overload.
"Minus" means that value is updated only if particular value has changed, not continuos but event driven. -9000ms is the most suitable setting in terms of the system load.
If you set e.g. 3000ms update rate in the graphic, OPC should set the same update rate to RTA board. It is possible to use 3sec update for some values, *but* not for all.
Use 1sec update rate with caution, only for few values, which really need fast update, like rolling force, roll gap position or mill speed.
> "I changed the update rate of some object at the control connection aspect"
Don't ! - Unless you understand what the subscription rates mean and what could go wrong on an Advant Controller.
Subscription rates should ONLY be set to 1,3 or 9 seconds or longer than 30. Serious performance problems can occur if you try to use other subscription rates on loaded Advant controller nodes - Including killing the subscription tasks which will break all objects of the same type.
xxxx = update rate in millieseconds (AC400 only support 1, 3 and 9 seconds)
s = if - (negative) send intermediate update on event.
9000 = susbscribe on 9s. No intermediate updates.
-9000 = subscribe on 9s *with* intermediate updates, eg into alarm state.
An intermediate update is driven by a change of the STATUS word (disturbance, alarm_unack, selected, etc).