Registration of an interface instance with PI APS

An interface instance must be registered with PI APS for its points to be synchronized. The PI APS Configuration Utility is the means for registering and un-registering interface instances with PI APS. When the PI APS Configuration Utility registers an interface instance, it creates a module in the Module Database on the PI Server that contains the points for the interface instance. The presence of this module indicates that the interface instance is registered with PI APS and most PI APS configuration settings for the interface instance are stored in this module or sub-modules under it. (For classic interfaces, PI APS also uses PI ICU configuration settings in the Module Database for the interface instance.) The PI APS Configuration Utility stores permanent and configurable settings for the new interface instance into the PI Module Database (PI MDB). An example of a permanent setting is the specific PI APS Connector that the PI APS Synchronization Engine calls while synchronizing the interface instance. After registration, this association cannot be changed without un-registering and re-registering the interface instance. When an interface instance is registered with PI APS, the values for most configurable settings are initialized to values that are built into the PI APS Configuration Utility. The exceptions, which are initialized with suggested values obtained from the PI APS Connector, are the scheduling frequency for synchronizing the interface instance and the specific actions to take when differences between PI points and data source tags are detected. For explanations of the dialog boxes that display or change configurable settings, including the default value for each option or parameter, see PI APS Configuration Utility.

When an interface instance is registered, the PI APS Configuration Utility also creates a folder for the interface instance under the %PIHOME%\APS folder. (The exact location of the %PIHOME% folder is established when PI API is first installed on a computer; the default path is \Program Files\PIPC on the primary hard drive of a 32-bit Windows system, or \Program Files (x86)\PIPC on a 64-bit Windows system.) The name of the folder for the new interface instance has the form InterfaceHost_InterfaceName_PIServer, where InterfaceHost is the host name on which the interface instance runs, InterfaceName is the short service name of the interface instance, and PIServer is the host name of the PI Server that contains the points for the interface instance.

After the folder is created, the PI APS Configuration Utility copies APSPoints.mdb (an empty Microsoft Access database file) from the APS folder into the new folder. PI APS uses the APSPoints.mdb database in each folder for long-term storage and communication between the PI APS Configuration Utility and Synchronization Engine. For example, this database contains the per-point synchronization settings for each of the PI points for the interface instance. Other uses of this database are discussed later in this chapter.

This folder is also the storage site for point logs. If point logs are enabled by the configuration settings, the PI APS Synchronization Engine may create one or more point log files in this folder each time the interface instance is synchronized. For more information on point logs, see Synchronization in PI APS

Registering an interface instance is a prerequisite for synchronizing its points but is not sufficient. Each registered interface instance has a configuration setting that controls whether synchronization is enabled or disabled.

Note: When initially registered, synchronization is disabled for the new interface instance.

This prevents a synchronization scan from occurring (with default configuration settings) before you configure PI APS parameters and options for the interface instance.