The LabVIEW Datalogging and Supervisory Control (DSC) Module provides multiple predefined alarms for the specified shared variable data types.

Predefined alarms for the specified shared variable data types:

  • HI_HI—Valid for numeric shared variables only
  • HI—Valid for numeric shared variables only
  • LO—Valid for numeric shared variables only
  • LO_LO—Valid for numeric shared variables only
  • Bad Status—Valid for all shared variables
  • Rate of Change—Valid for numeric shared variables only
  • Value—Valid for Boolean and U32 bit field shared variables only

    • You can enable and configure alarms and events for shared variables by using the following methods:

    • Shared Variable Properties dialog box — You can enable and configure alarms and events for shared variables in the Shared Variable Properties dialog box. Access this dialog box by right-clicking a shared variable in the Project Explorer window and selecting Properties from the shortcut menu.
    • Multiple Variable Editor window — You can use the Multiple Variable Editor window to enable and configure alarms and events of multiple shared variables.
    • Distributed System Manager — You can use the Distributed System Manager to configure parameters of shared variable alarms.

    Before the DSC Module can log alarms and events, you must enable alarms and events logging. Right-click a LabVIEW project library in the Project Explorer window and select Properties from the shortcut menu. Select DSC Settings: Database from the Category list. On the Citadel page or Relational Database page, place a checkmark in the Enable Alarms and Events Logging checkbox.

    If you configure a shared variable for data or event logging to the Citadel database but the Shared Variable Engine (SVE) cannot establish a connection to the Citadel database, the SVE triggers an alarm and logs the data to the default database.

    You can use the DSC Module to create user-defined alarms and events. User-defined alarms and events are not associated with a shared variable. You can use user-defined alarms and events for error handling and event triggering to detect when an application runs abnormally. LabVIEW logs the user-defined alarm or event to the Citadel historical database.