PointSource

The PointSource is a unique, single or multi-character string that is used to identify the PI point as a point that belongs to a particular interface. For example, the string Boiler1 may be used to identify points that belong to the MyInt interface. To implement this, the PointSource attribute would be set to Boiler1 for every PI point that is configured for the MyInt interface. Then, if /ps=Boiler1 is used on the startup command-line of the MyInt interface, the interface searches the PI Point Database upon startup for every PI point that is configured with a PointSource of Boiler1.

Before an interface loads a point, the interface usually performs further checks by examining additional PI point attributes to determine whether a particular point is valid for the interface. For additional information, see the /ps parameter. If the PI-API version being used is prior to 1.6.x or the Data Archive version is prior to 3.4.370.x, the PointSource is limited to a single character unless the SDK is being used.

• Case-sensitivity for PointSource Attribute

  The PointSource character that is supplied with the /ps command-line parameter is not case sensitive. That is, /ps=P and /ps=p are equivalent.

• Reserved Point Sources

  Several subsystems and applications that ship with PI are associated with default PointSource characters. The Totalizer Subsystem uses the PointSource character T, the Alarm Subsystem uses @ for Alarm Tags, G for Group Alarms, and Q for SQC Alarm Tags, Random uses R, RampSoak uses 9, and the Performance Equations Subsystem uses C. Do not use these PointSource characters or change the default point source characters for these applications. Also, if a PointSource character is not explicitly defined when creating a PI point, the point is assigned a default PointSource character of Lab (PI 3). Therefore, it would be confusing to use Lab as the PointSource character for an interface. Pointsource 9 should be used for the Ramp Soak interface simulator.

  Note: Do not use a point source character that is already associated with another interface program. It is acceptable to use the same point source for multiple instances of an interface.