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The PI Adaptor standardised access to OSIsoft PI historian servers, hiding the complexity of obtaining data from PI and facilitating visualisation of data via consuming applications. It provides the ability to read and write time series tag data to and from the PI historian.
The PI Adaptor requires the OSIsoft PI SDK to be installed to access real-time and historical data from OSIsoft's PI historian. This requires a license for the OSIsoft PI SDK, which is a third party component.
Features
PI Server Version Support
The PI Adaptor supports version 3 of the PI Server. Version 3.3 or later is recommended due to the availability of the ArcMaxCollect configuration parameter, which was fixed to 150000 in versions prior to 3.3. Note that the adaptor requires the PI Software Development Kit (PI SDK) v1.4.4 or later to be installed as a prerequisite.
Data Type Support
The following PI Point data types are supported:
- Float16
- Float32
- Float64
- Int16
- Int32
- Digital
- String
This means the Adaptor supports all numeric, string, and digital type tags.
Sample Methods
The PI Adaptor supports all standard time series data sample methods used by IFS OI Server: Raw, Adaptive Raw, Average, Last Known Value, and Linear Interpolate. For more information on how these sample methods are calculated, see Data Transformation & Sample Methods.
For data fetches using the Adaptive Raw sample method, the PI Adaptor will invoke the PlotValues() function of the historian API instead of performing the default reduction on raw data. This should significantly reduce the overhead involved in servicing Adaptive Raw requests for larger fetch ranges.
Average Calculation Methods
The PI Adaptor supports the TIME average calculation method, which is used when retrieving data using the Average sampling method. The supported methods are:
- Time Weighted Average - Weights the values in the calculation by the time over which they apply. Interpolation is based on the step attribute of the point. Interpolated events can only be generated at the boundaries if the PIValues collection time range is wider than the calculation time range.
Daylight Savings Time & Time Zones
The PI Adaptor stores all timestamps in UTC (Universal Time Coordinated) format, meaning that timestamps are independent of the local time zone preferences and Daylight Savings Time (DST) issues.
At the point of displaying and using the entity values in pages and trends, the local time zone is used, allowing data to be displayed with local timestamps.
Logging
The IFS OI Logger is used by the PI Adaptor to log warning, error, information, and debug messages.
Logging of debug messages results in significant overhead due to the large amount of extra logging, and should only be turned on when troubleshooting a specific issue if directed by IFS OI Customer Support. It should not be enabled for general usage.
The IFS OI Logger component should be installed to view the messages via the IFS OI Log Viewer application.
PI Adaptor Settings
The following table lists the adaptor's parameters, along with the name and type to be used in the Import/Export spreadsheet.
| Parameter | Description and example | Name | Type |
| Server | Name of the server machine on which the historian is hosted. | Server | String |
| User ID | User ID to use to connect to the historian. | User Id | String |
| Password | Password for the User ID used to connect to the historian. | Password | EncryptedString |
| Use Point Cache | The cache retains the tag metadata used to look up recorded values from PI. Enabling this cache may save time when fetching data for a tag that has been previously fetched by the same adaptor instance. Note that enabling this caching will increase the potential memory consumption of each adaptor instance for this datasource. Options: True, False. | Use Point Cache | Boolean |
| Questionable Confidence Level | Data points in PI may be stored with a "questionable" flag set. Points that are flagged as questionable will have their confidence value set to what is specified here, while points without the flag will have a confidence value of 100. Acceptable range: 0-100. | Questionable Confidence Level | Integer |
| Fetch Concurrency Limit | The number of tags that may be fetched in parallel from the PI server per adaptor instance. Note that the maximum number of simultaneous data fetches that can occur for this datasource is the concurrency limit multiplied by the maximum pool size. Default: 32. | Concurrency Limit | Integer |
| Allow Write | Whether this data source should allow IFS OI Server client applications to write data to tags on the historian. Options: True, False. | AllowWrite | Boolean |
| Allow High Availability | This setting allows the PI Adaptor to connect to other PI servers within a collective of PI servers. PI organises servers in "collectives", where one is designated "primary" and is the default connection target even if another server in the collective is specified. Enabling this option will allow the PI client (configured separately on the hosting system) to use its own configuration for which servers to use. Options: True, False. | AllowHighAvailability | Boolean |
| Use Custom Floating Point Conversion | When this flag is set to false, the adaptor will use the .NET runtime's built-in conversion algorithm for converting PI floating-point values to decimal. If it is set to true, then a custom algorithm will be used which can produce more accurate decimal values. Options: True, False. | UseCustomFloatingPointConversion | Boolean |
| Number of Decimal Places For Custom Floating-point Conversion | This setting specifies the number of decimal places to round to when the custom algorithm is used for converting PI floating-point values to decimal. | NumberofDecimalPlacesForCustomFloating-pointConversion | Integer |
Release History
- PI Adaptor Features 4.10.2
- Improved handling of Adaptive Raw requests
- PI Adaptor Features 4.9.7
- Added Use Custom Floating-point Conversion, Number of Decimal Places For Custom Floating-point Conversion
- PI Adaptor Features 4.7.0
- Added Allow High Availability
- PI Adaptor Features 4.3.1
- Added Use Point Cache, Questionable Confidence Level, Fetch Concurrency Limit, Allow Write
- PI Adaptor Features 4.3.0
- Initial version