Purpose
This Technical Note describes a documented issue in Vaisala viewLinc Enterprise Server 5.1 where an alarm record may remain in the historical database without a matching deactivation timestamp. It also explains the Vaisala-provided tool used to correct these records.
Condition Description
Under certain conditions in viewLinc 5.1, an alarm that was acknowledged and deactivated may still appear as active in the Alarm Report, showing a duration of months or years, even though no active alarm ticket appears in the Alarms window. Operationally, the alarm has ended, but the deactivation event was not recorded in the historical database.
Vaisala has identified these contributing causes:
- In earlier viewLinc versions, a timestamp-resolution interaction could cause an acknowledgement event and a deactivation event for the same alarm to share the same timestamp and identifier key. In that case, the acknowledgement record could overwrite the deactivation record in the historical database.
- Server-clock adjustments could place the recorded deactivation time before the recorded activation time. The standard Alarm Report and standard remediation logic do not treat this as a valid activation/deactivation pair.
- Interruptions while transferring a deactivated alarm ticket from the configuration database to the historical database—for example, power loss, hardware failure, or an unhandled software exception—can leave the activation record in the historical database without its matching deactivation record.