The state change is internally done by automatic calling the methods
Activate,
Inactivate and
Acknowledge so that the alarm item reaches the new required state.
In some cases it is possible to pass directly from the current state to the required state by calling one of the above mentioned methods. In other cases it is not possible to pass directly from one state to another state but some of the above mentioned methods has to be called internally more times and the alarm item must pass through several other states before it is moved to the required state.
The alarm in the state "
inactive acknowledged [green]" can be moved to the state "
active unacknowledged [red]" directly by calling the
Activate method.
The alarm in the state "
active acknowledged [yellow]" can be moved to the state "
inactive unacknowledged [blue]" by successive calling the methods
Inactivate ("
inactive acknowledged [green]"),
Activate ("
active unacknowledged [red]") and finally
Inactivate ("
inactive unacknowledged [blue]").
The real sequence of gradually called methods can be found in the alarm history.
This method can be used first of all in case when the alarms are implemented outside PROMOTIC (e.g. in the PLC device) and PROMOTIC is using them for the visualization. By the
onUserItemAction event it is possible to catch even the acknowledgment of these alarms with the result that the acknowledgment in the PROMOTIC system is suppressed and instead of this the information about the acknowledgment is sent to the system reponsible for the alarms (e.g. into the PLC device).
The method is
synchronous, it means that it is processed immediately by the alarm subsystem. Nevertheless writing the history to disk is
asynchronous, it means that this method passes the request for writing into the history of alarms subsystem, it is placed into the queue of requests and it is processed later by the alarm subsystem.