Access the Last 10 Values of a Tag

About this task

This topic describes how to access the last 10 values of a tag up to the current time. The difference in the timestamp of consecutive values depends on the time resolution of the tag. For example, if the time resolution is seconds, the timestamp of consecutive values of the tag will be one second apart.
Note: If a tag name contains a comma or a semicolon, you cannot view the last 10 values of the tag.

Procedure

  1. Access Configuration Hub.
  2. In the NAVIGATION section, under the Configuration Hub plugin for Historian, select Tags.
    A list of all the tags appears.
  3. If you want to narrow down the search results, select Search. Enter the search criteria, and then select Search. You can add more attributes by selecting Add Attribute. You can enter a name or a value partially or use the wildcard character asterisk (*).
    The list of tags are filtered based on the search criteria.
  4. If you want to access the last 10 values of a single tag, right-click the tag (or select ), and then select View Last 10 Values.
    The last 10 values of the tag appear, along with the timestamp and quality of each value. You can switch between the trend view and the table view.
  5. If you want to access the last 10 values of multiple tags, select the check boxes corresponding to the tags, right-click (or select ), and then select Trend. You can select up to 10 tags.

    In table view you can view data attributes which are introduced to store the 128-bit subquality for every sample.

    Note: SCADA applications such as Habitat support data samples with several quality types. To support such SCADA applications, Historian is now enhanced to store up to 128-bit quality types, which are stored in the data attributes. These attributes are extended qualities that you can store more than the regular qualities and subqualities (such as good and bad). In addition to regular qualities, the HAB collector collects extends qualities such as replaced, suspect, garbage, old, and so on.

    The Data Attributes are displayed in the table view along with Timestamp, Value, and Quality. Data Attributes are supported for Current Value, Raw by Number, Raw by Time, Lab, and Lab to Raw. In addition:

    • For an array tag, all the values in the array appear for each timestamp.
    • For a tag using an enumerated set, values of all the states appear for each timestamp.
    • For a tag using a user-defined data type (UDT), values for all the fields appear for each timestamp.
  6. For the selected tag, to view the results in a table, select Table.
    Tip: You can also filter the values by changing the duration, sampling type, time interval, engineering units, and so on by selecting .

  7. For the selected tag, to view the results in a trend chart, select Trend.