Characteristics of priority zero (0) alarms in Vista

Issue

It may be useful to have logic in Menta programs trigger an event in Vista so that it can be recorded and stored in the event log.

Product Line

TAC Vista

Environment

  • Vista Workstation
  • Menta

Cause

Alarms that have the Priority parameter set to 0 are used for info purposes only and only show in the event viewer and not the alarm viewer (queue).

Resolution

Events can be triggered by a Menta program by creating an Alarm block in Menta and setting the Priority parameter to zero. This causes the alarm to only function as an event and keeps it from showing up in the alarm queue.

The following is taken from the Menta Technical Manual:

The alarm priority is specified with the Priority parameter. There are 10 levels, 1 to 9 and 0, where 1 is the highest. Events with priority 0 (Information messages) have the lowest priority. They are not placed in the alarm database of TAC Vista and do not appear in the alarm overview.

An example where using a priority zero alarm might be useful is to record as an event whenever an air handler enables and disables its economizer. This would be done as follows:

1. An ALARM block is created and named EVENTS\ECONOMIZER_ENBL. The Priority parameter is set to 0. Alarm Control is set to the standard alarm control object which is $Alr_Cntrl. The Tripped Alarm text is set as "ECONOMIZER ENABLED" and the Reset Alarm text is set as "ECONOMIZER DISABLED".

2. The ALARM block is then connected to the Economizer function.

Now an event will be generated each time the economizer is enabled and disabled but an alarm will never pop up in the alarm viewer. An Events Viewer object could now be created to make it easier to view just economizer events without everything else. This is done as follows:

  • In Vista Workstation right click the Root object and select New > Object > Viewer - Events. Type in a description and enter the Object ID of the economizer event that has been created. This can be found by locating an instance of the economizer event in the standard event viewer and copying the Object ID from there.

  • The event viewer could be set up to display all priority 0 alarms instead of one specific event type by entering a 0 in Priorities in the Alarms section under the Event Specifics tab.

  • The amount of time displayed in the event viewer can be filtered under the Date and Time tab.
  • It may be useful to remove unneeded columns from the new event viewer so that only the relevant information will be displayed. In this example everything is unselected except Time, Object ID and Text under the Select Column(s) tab.

The event viewer will automatically update and could be used for real-time monitoring of whatever event(s) it has been configured to display.