The following retrieval modes can be set for a PI data source:
|
Retrieval mode |
Description |
|
CurrentValue |
Returns the most current value from the PI system snapshot. |
|
Even |
Interpolated values are returned from the PI archive, using the Start Time, Duration, and Max Points parameters. |
|
Compressed |
Raw values are returned from the PI archive with no interpolation, using the Start Time, Duration, and Max Points parameters. |
|
Total |
The time-based total is converted to a total for the entire time range. If some of the data are bad, the calculated total is divided by the fraction of the time period for which there were good values. If the engineering units for the point do not match default time units for the system, the resulting value must be properly adjusted using a conversion factor. |
|
Minimum |
Returns the minimum value in a specific time period. |
|
Maximum |
Returns the maximum value in a specific time period. |
|
Std Dev |
Returns the standard deviation of values in a specific time period. The standard deviation calculation uses the first good value received as a standard value. |
|
Range |
Returns the difference between the minimum and maximum values in a specific time period. |
|
Average |
Returns the time-weighted average value in a specific time period. |
|
Mean |
Returns the mean value in a specific time period. |
