What Methods are Available for Accessing OSIsoft’s PI Server?

When someone jumps into a project without thinking things through we’ll often say that he or she took the “hard way”.  While the easy way usually involves a little more thought at the start, it typically results in a faster and more satisfactory finish.  Racing into a project often results in delays, cost overruns, and general dissatisfaction.  This is especially true in the world of software application development.  Most every software technology firm can share stories to corroborate the value of a well-planned project versus the hazards of a poorly planned effort.

OSIsoft’s PI System is widely recognized as the automation market’s leading data historian.  The architecture of the PI Server is such that it provides manufacturers with a highly secure, scalable environment for capturing and storing their production data.  Beyond capture and storage the PI Server also makes the data available to other applications for the purpose of providing operational intelligence.  The consideration put into the PI Server’s development is reflected in OSI’s market position – they’ve made it easy for manufacturers to succeed.

Here are three different ways by which software applications can connect with the OSI PI Server – some easier than others – and tap into the data stored therein:

OPC-HDA

As with other historian solutions the data that’s stored within the PI Server can be retrieved via OPC Historical Data Access (OPC-HDA).  While this is a common approach, OPC-HDA data access requires thorough knowledge of DCOM in order to securely transfer data across networks.  The complexity and security concerns associated with DCOM can be significant which makes it less than ideal for staff at many facilities.

OLE DB

Another popular approach for accessing historical data is OLE-DB – an API from Microsoft.  This method eliminates the security issues frequently encountered with use of OPC-HDA.  However, programmers must possess a strong grasp of the specific data structure and the queries required to access the data when configuring OLE-DB.  While OSI has standardized those data calls relative to accessing the PI Server, the data calls used with other historians can be unique to each implementation.

PI-SDK / AF-SDK

OSIsoft’s Software Development Kit (SDK) facilitates access to data that’s first captured then stored in its PI Server.  As a solution, the PI-SDK both eliminates the security issues associated with OPC-HDA and it standardizes the structure by which data calls are configured.  In that fashion the PI-SDK overcomes the two primary deficiencies that exist with OPC-HDA and OLE DB.

From a design and interoperability standpoint the team at OSIsoft took the easy route – they mapped out a clear and long-term plan for the development and support of their PI Server.  Their choice of the easy path is clear in terms of how OSI PI users can access their data.  The PI Server supports the industry’s most common communication methods, and the PI SDK provides an ideal means for tapping into data.

Control Station has a long history of working with the PI Server from OSIsoft.  Indeed, PlantESP is the only controller performance monitoring product that fully utilizes the PI-SDK to access process data natively from the PI Server – a feature that has facilitated numerous PlantESP deployments.  As OSI’s newest partner, Control Station will showcase PlantESP this week during the OSI User Conference.