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This tag looks for active or unacknowledged alarms matching a given set of characteristics. It can be used to build a trigger for an output or another alarm. For example, you might use it to trigger a warning system when any alarm with a given priority in a given area is active.
The value of the Alarm Status tag will be either 1 or 0 depending on whether any matching alarms have been triggered.
If this tag is a child of an Alarm Database, it will look only for alarms in that database. Otherwise, it will look for all alarms in all Alarm Databases. Use with care if you have a large number of alarms in your system.
Alarm Status properties ID tab
The ID tab of every tag includes the same common elements: Name, Area, Description, and Help ID.
Name:
Uniquely identifies each tag in the application. If the tag is a child of another, the parent names will be displayed in a separate area before the name field.
You may right-click on the tag's name to add or remove a conditional start expression.
Area
The area field is used to group similar tags together. By defining an area, you make it possible to:
- Filter for particular tag groups when searching in the tag browser
- Link dial-out alarm rosters to Alarm tags having a particular area
- Limit the number of tags loaded upon startup.
- Filter the alarm display to show only certain areas.
- Filter tag selection by area when building reports
When working with Parent-Child tag structures, the area property of all child tags will automatically match the configured area of a parent. Naturally, you can change any tag's area as required. In the case of a child tag, the field background will turn yellow to indicate that you have applied an override. (Orange in the case of user-defined types. Refer to Configuration Field Colors)
To use the area field effectively, you might consider setting the same Area for each I/O driver and its related I/O tags to group all the tags representing the equipment processes installed at each I/O device. You might also consider naming the Area property for the physical location of the tag (i.e. a station or name of a landmark near the location of the I/O device). For serial port or Roster tags, you might configure the Area property according to the purpose of each tag, such as System or Communications.
You may define as many areas as you wish and you may leave the area blank for some tags (note that for Modem tags that are to be used with the Alarm Notification System, it is actually required that the area field be left blank).
To define a new area, type the name in the field. It will immediately be added. To use an existing area, use the drop-down list feature. Re-typing an existing area name is not recommended since a typo or misspelling will result in a second area being created.
There is no tool to remove an area name from VTScada since such a tool is unnecessary. An area definition will exist as long as any tag uses it and will stop existing when no tag uses it (following the next re-start).
Description
Tag names tend to be brief. The description field provides a way to give each tag a human-friendly note describing its purpose. While not mandatory, the description is highly recommended.
Tag descriptions are displayed in the tag browser, in the list of tags to be selected for a report and also on-screen when the operator holds the pointer over the tag’s widget. For installations that use the Alarm Notification System, the description will be spoken when identifying the tag that caused the alarm.
The description field will store up to 65,500 characters, but this will exceed the practical limits of what can be displayed on-screen.
This note is relevant only to those with a multilingual user interface:
When editing any textual parameter (description, area, engineering units...) always work in the phrase editor. Any changes made directly to the textual parameter will result in a new phrase being created rather than the existing phrase being changed.
In a unilingual application this makes no difference, but in a multilingual application it is regarded as poor practice.
Help Search Key
Used only by those who have created their own CHM-format context sensitive help files to accompany their application.
Alarm Status properties Alarm tab
The alarm tab is used to define which alarms will be counted an instance of the Alarm Status tag. Use the fields to select the characteristics that must be found in an alarm to be included in the count.
Low Alarm Priority
Select the lower end of the range of alarm priorities to be filtered for. Any alarm with a priority between the Low Alarm Priority and the High Alarm Priority, and matching the remaining conditions will be included in the filter. The minimum priority cannot be set above the maximum priority.
To filter for alarms of only a given priority, set both the Low Alarm Priority and the High Alarm Priority to that value.
High Alarm Priority
Select the upper end of the range of alarm priorities to be filtered for. Any alarm with a priority between the Low Alarm Priority and the High Alarm Priority, and matching the remaining conditions will be included in the filter. The maximum priority cannot be set below the minimum priority.
To filter for alarms of only a given priority, set both the Low Alarm Priority and the High Alarm Priority to that value.
Area Filter
Select the area that the alarm must be configured within to be included in the filter. Areas shown in the list include all system alarm areas as well as developer-created areas.
Name Filter
Use this field to restrict the list of filtered alarms to only those matching a given name. The * wildcard may be used to permit selection on a set of similar names. For example, "East*" will match "East Pump Alarm", "East Tank Alarm", etc.
Alarm List
Options include "Active", "Unacknowledged" and "Current". Only one option may be chosen. Restricts the filter to only those matching a particular list type.
Alarm Status properties Display tab
When this tag is represented on screen by widgets that can use a Style Settings tag, you can save development time by choosing the Style Settings tag that holds the correct display configuration for this tag instance.
The default configuration will use System Style, the default style tag that is automatically part of every new VTScada application.
Alarm Status Tag Widget
The following widget is available to display information about your application’s Alarm Status tags:
