Step 5: set alarms

smc_create_alarm_ex sets an alarm on any numeric data item (except for IDs) in a view. When specifying an alarm for a particular data item in a live connection, an application supplies a callback function that is invoked when the alarm is triggered.

The Historical Server cannot call a callback function, but it can write to a log file or execute a procedure each time an alarm is triggered.

An example of the type of actions an application can execute upon the triggering of an alarm is to log a message, which is one of the features provided by Historical Server.

You can add or drop an alarm at any time. The change in alarm specification takes effect as of the next refresh.

NoteMonitor Client Library applies alarms after it applies filters.

See the code sample on page 25.