If your database has items that have their alarms enabled or disabled unexpectedly, the most probable cause is that:
- The Independent feature is disabled and Logic programs, Schedules, and/or Method Calls are triggering the Enable Alarms or Disable Alarms action automatically.
When the Independent feature is disabled on the server:
- Enable Alarms is available when the item’s Overall ‘Disable Alarms’ state is 1 (Disabled). When Enable Alarms is triggered, it is applied almost immediately, irrespective of any other User Types or disable alarms durations.
- Disable Alarms is available when the item’s Overall ‘Disable Alarms’ state is 0 (Enabled). When Disable Alarms is triggered, it is applied almost immediately, irrespective of the enabled or disabled status of the other User Types.
Example:
Your server settings could define a 1 hour Fixed Duration for Disable Alarms. So when you select Disable Alarms for a point, you may expect the point’s alarms to be disabled for an hour. This may not be the case, as a Logic program, Schedule or Method Call could trigger Enable Alarms within the hour period. If Independent is disabled, the Enable Alarms action is applied, irrespective of the hour period.
If Independent is enabled:
- Enable Alarms can be triggered by any User Type that is currently disabling the alarms (i.e. has previously called the Disable Alarms action on the item or one of the item’s parents). Triggering Enable Alarms will change the flag for the User Type that triggered the action, but this may not change the Overall ‘Disable Alarms’ state of the item—Enable Alarms will only change the Overall state if all of the flags are set to 0 (Enabled).
The ‘Disable Alarms’ flags for the User, Logic, Schedule and Method Calls User Types are all set to Enabled by default. - Disable Alarms can be triggered by any User Type that currently has its ‘Disable Alarms’ flag set to 0 (Alarms Enabled). Triggering Disable Alarms will change the Overall ‘Disable Alarms’ state of the item and so will cause its alarms to be withheld.
Further Information
Independent: see Define whether User Types can Disable Alarms Independently in the ClearSCADA Guide to Server Administration.