Supported features

The following table describes features that this interface supports. Some features are described in more detail after the table.

• Outputs from Data Archive to data source

  The OPCHDA Server must have the method: SyncUpdate::InsertReplace implemented for outputs from PI to work. Not all OPCHDA Servers implement this optional method. For example, Honeywell Experion OPCHDA Server does not implement this method.

• Uses PI SDK

  The PI SDK and the PI API are bundled together and must be installed on each interface node. This interface does not specifically make PI SDK calls.

• Source of Time stamps

  The interface uses the time stamps from the OPCHDA Server. The time stamps will adjust to the time difference from the OPCHDA Server and the Data Archive.

  It is possible to use the /TSU command-line parameter to adjust this behavior of the interface.

  /TSU is an option that must be selected with caution. With this option, the time stamps received from the OPCHDA Server will be sent to the Data Archive directly without any adjustments. If the OPC Server time is ahead of the Data Archive time, this option will result in the Data Archive receiving time stamps that are in the future. Consequently, the data will not be written to the . The user should select this option only if the clock settings on both servers are appropriate (that is, either the same or the clock is ahead) and the clocks are either automatically synchronized or clock checks are made frequently.

  If the user is getting error -11049 in the pipc.log file, the clocks on the Data Archive and on the interface node must be checked. This error occurs when the interface has sent a timestamp that is outside of the range for the PI archives.

• History Recovery

  History recovery is performed on a per-point basis for both scanned and event tags. When performed at startup, the interface uses the timestamp of the last good Data Archive value or the /hi=x command-line parameter, whichever is closer to the current time, to determine how far back in time to retrieve data. When performed after the connection to the OPC HDA Server has been lost and then re-established, the interface uses the timestamp of the last good PI Archive value to determine how far back in time to retrieve data. In this context, a "good" Data Archive value means one that is not a system digital state. System digital state values within the history recovery time period are deleted from PI System when the interface is running in History Recovery Only mode.

• UniInt-based

  UniInt stands for Universal Interface. UniInt is not a separate product or file; it is an AVEVA-developed template used by developers integrated into many interfaces, including this interface. The purpose of UniInt is to keep a consistent feature set and behavior across as many of our interfaces as possible. It also allows for the very rapid development of new interfaces. In any UniInt-based interface, the interface uses some of the UniInt-supplied configuration parameters and some interface-specific parameters. UniInt is constantly being upgraded with new options and features. The PI Universal Interface (UniInt) Framework User Guide is a supplement to this manual.

• Failover

  • Server-Level Failover

    This interface supports server-level failover which allows the interface to continue to collect data from the currently active OPCHDA server when two servers are running in unison and the primary server shutdown or an unexpected communication failure occurs.

  • UniInt Failover Support

    UniInt Phase 2 failover provides support for cold or warm failover configurations. In warm and cold failover configurations, you can expect a small period of data loss during a single point of failure transition. This failover solution requires that two copies of the interface be installed on different interface nodes collecting data simultaneously from a single data source. Phase 2 failover requires each interface have access to a shared data file. Failover operation is automatic and operates with no user interaction. Each interface participating in failover has the ability to monitor and determine liveliness and failover status. To assist in administering system operations, the ability to manually trigger failover to a desired interface is also supported by the failover scheme.

    Details for configuring this interface to use failover are described in the PI Universal Interface (UniInt) Framework User Guide .

• SetDeviceStatus

  The interface is built with a version of UniInt that is newer than 4.3.0.x and that supports interface health points. The health point with the point attribute Exdesc = [UI_DEVSTAT], is used to represent the status of the source devices. The following events can be written to the point:

  • "Good" - This value indicates that the interface is properly communicating and reading data from the devices. If no data collection points have been defined, this indicates the interface has successfully started.

  • "3 | 1 devices(s) in error" - This value indicates that the interface has determined that the listed device(s) are offline. A device is considered offline when the connection to the HDA Server has failed.

    Note: Refer to the PI Universal Interface (UniInt) Framework User Guide for more information on how to configure health points.

• Vendor Software Required

  The OPCHDA Server may run on the same system as the interface, or it may run on another system.

  • The OPC Security standard

    The OPC Foundation published the OPC security standard in October 2000. It provides an interface for the client and server to agree to either use NT security, where the server interrogates the system to get the client's Security ID, or to use OPC Private security, where the client passes a userid and password to the server. It is important to note that the userid and password are sent in clear text, meaning that they can be seen by anyone with a sniffer on the network.

    Few OPC servers have implemented the OPC security standard. It does allow for more granular control over who can read and write individual OPC Items, however the OPC Private security design, by passing credentials in clear text, is inherently insecure. OPC servers can implement NT security without the need for clients to implement the OPC security standard at all.

• Additional PI Software

  The PI HDA Tool is a product that ships with the interface to assist in configuring and troubleshooting of the interface.

• Device Point Types

  By default, the interface requests the following data types:

  PI Point Type	OPCHDA Server Data Type
  Digital	2-byte Integer (VT_I2)
  Int16	2-byte Integer (VT_I2)
  Int32	4-byte Integer (VT_I4)
  Float32	4-byte Float (VT_R4)
  FLoat64	8-byte Float (VT_R8)
  String	String (VT_BSTR)