Time Filtered function

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.

Expression(s)

A Boolean performance equation that the function evaluates. See Expressions.

To specify multiple expressions, enter a range of cells that contain complete expressions. 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.

Time interval

The frequency that the function returns calculated values during the time period. Enter a value and time unit. For example, enter 15m (15 minutes) to return a value for every 15-minute interval in the time period. See Learn about time-interval specifications.

Time units

The units of time in which the function returns the result.

Required.

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.

Show start time

Select this check box to show the start time of the time interval used to calculate the returned value. PI DataLink shows the start time in a column to the left or in a row above returned values. Only available if you specify Time interval.

Show end time

Select this check box to show the end time of the time interval used to calculate the returned value. PI DataLink shows the end time in a column to the left or in a row above returned values. Only available if you specify Time interval.

Show percent good

Select this check box to show the percentage of time that good values were returned during the array time period. PI DataLink shows the percent-good values in a column to the right or in a row below returned values.

Good values are recorded values that Data Archive determined were valid, and not in an error state. You might use the percentage of good values to assess the reliability of calculations built on PI point values, particularly if you use calculated values in further calculations.

For example, if a time period includes bad data, the resulting time-weighted total equals the total divided by the fraction of the interval where good data is available. This normalization assumes that the average over the time period with bad data is equivalent to the average value over the entire period. Thus, the average becomes less reliable if a large fraction of the time period contains bad data.

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 Expression(s), PI DataLink automatically selects Column or Row to match the orientation of the items.