Custom digital conversion function support for the PI-OASyS interface

It is possible to create conversion routines that are able to re-map data from AVEVA Enterprise SCADA status points to values that are meaningful in the PI Servers.

There are some AVEVA Enterprise SCADA systems that use the PI system as storage for Historical data. When the existing AVEVA Enterprise SCADA system is upgraded to an AVEVA Enterprise SCADA solution, continuity of the PI data can be maintained. This could be a problem if any status values in the new AVEVA Enterprise SCADA system do not match the values in the old system.

Note: AVEVA has provided sample source code of a library called libPiDigitalConvert.dll. The libPiDigitalConvert.dll library contains specific data conversion functions to handle the data transformation. To build a fresh instance of this library, refer to RealTime PI software development kit (SDK) examples.

Any digital PI Tag which receives data from a RealTime database (RTDB) status point can be configured to use a conversion function. The PI Tag field exdesc is used to configure a data conversion function name along with the AVEVA Enterprise SCADA path. The syntax for this field is:

<tablename>.<point name>.<field name>;CNVFUNC=<conversion function name>

Example

Using the libPiDigitalConvert.dll library, which implements the data conversion function VectorDigConvert, the exdesc is as follows:

status.status_1.cursta;CNVFUNC=VectorDigConvert

The data conversion function name must match the function name in the library.

A PI Tag can configure the exdesc field during point creation. The exdesc field can also be modified in runtime for a given point. After saving the modification, the PI-OASyS interface will apply the specified custom data conversion function to values as they are collected.