Compressed Data function

• If you select the Time range option, the Compressed Data function returns all the values of a PI point or PI AF attribute along with a count of values that occur during a specified time period.

• If you select the Number of values option, the Compressed Data function returns a specific number of point values or attribute values beginning at a certain time.

  Note: Values stored in the archive of Data Archive undergo a compression algorithm that removes all values that represent the same slope. Values stored in the Data Archive snapshot have not undergone this compression algorithm. If you specify the current time in the time period of the Compressed Data function, the function retrieves a snapshot value for that time. That snapshot value might not be subsequently stored in the archive due to compression.

  Input	Description
  Root path	The common path to specified data items, including those in expressions. Valid entries include: PI Data Archive server name if the data item is a PI point. PI AF server and database if the data item is a PI AF attribute. Blank if the data item is a PI point on the default PI Data Archive server. See Data items.
  Data item(s)	One or more PI point names or PI AF attribute names, for which the function returns values. To specify multiple data items, enter a range of cells that contain PI point names or PI AF attribute names. The function returns values for each. Required.
  Start time	The start of the time period for which the function returns values. See Time inputs. Required.
  End time	The end of the time period for which the function returns values. See Time inputs. Required if you select the Time range option.
  Number of values	The number of values that the function returns, beginning at Start time. Required if you select the Number of values option.
  Backwards in time	Select this check box to return values recorded at Start time and earlier. Available if you select the Number of values option and enter a value in the Number of values field. If you enter a cell reference in the Number of values field, this check box is disabled. Instead, enter a negative number in the referenced cell to have the same effect.
  Filter expression	A Boolean performance equation that the function uses to filter values. When the expression evaluates to false, the function excludes corresponding values. See Filter expressions.
  Mark as filtered	Select this check box to insert the label Filtered in place of a value or block of values that the function filtered from the output based on Filter expression.
  Boundary type	The method that the function uses to determine which values to return near the start time or end time: inside (default) Returns values at start and end times, if they exist, or the nearest values that occur within the range. outside Returns the nearest values that occur immediately outside the range. interpolated Returns interpolated values at the start and end times. See Interpolated values. auto Returns interpolated values, but uses the inside method for data items with step attributes.
  Output cell	The worksheet cell where the function writes the resulting function array. If you select a cell before you open the function task pane, PI DataLink inserts the selected cell into the Output cell field. Specify the top-left corner of the function array. PI DataLink expands the range downward and to the right of the output cell, as necessary to return specified data. PI DataLink might overwrite adjacent cells. If you specify a multi-cell array in the Output cell field and the specified array is larger than the resulting function array, PI DataLink pastes the function formula in the unneeded cells of the specified array.
  Hide count	Select this check box to hide the count of returned values and show only returned values. Available if you select the Time range option.
  Show time stamps	Select this check box to show the time stamp that corresponds to each returned value. PI DataLink shows time stamps to the left of values displayed in a column or above values displayed in a row.
  Show value attributes	Select this check box to show the extended status bits associated with returned values. Possible status bits include: A Annotated. Indicates the value has a comment. S Substituted. Indicates the value has changed from its originally recorded value. Q Questionable. Indicates that there is some reason to doubt the accuracy of the value. PI DataLink shows value attributes in a column to the right of the values.
  Show annotations	Select this check box to show annotations associated with returned values. Annotations contain notes or comments that describe a data value. PI DataLink shows annotations in a column to the right of the value.
  Column	Select this option to return values in a column.
  Row	Select this option to return values in a row. Note: If you specify a range of items in Data item(s) or a range of expressions in Expression(s), PI DataLink automatically selects Column or Row to match the orientation of the specified range.

See also

• PICompDat()

  Specify a time range without a filter expression.

• PICompFilDat()

  Specify a time range with a filter expression.

• PINCompDat()

  Specify a number of values without a filter expression.

• PINCompFilDat()

  Specify a number of values with a filter expression.