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Data sources

Tagreader supports connecting to PI and IP.21 servers using a Web API interfaces. When calling certain methods, the user will need to tell tagreader which system and which connection method to use. This input argument is called imstype , and can be one of the following case-insensitive strings:

  • piwebapi : For connecting to OSISoft PI Web API
  • aspenone : For connecting to AspenTech Process Data REST Web API

Listing available data sources​

The method tagreader.list_sources() can query for available PI and IP.21 servers available. Input arguments:

  • imstype : The name of the IMS type to query. Valid values: piwebapi and aspenone.

The following input arguments are only relevant when calling list_sources() with a Web API imstype ( piwebapi or aspenone ):

  • url (optional): Path to server root, e.g. "https://aspenone/ProcessData/AtProcessDataREST.dll" or "https://piwebapi/piwebapi". Default: Path to Equinor server corresponding to selected imstype if
  • imstype is piwebapi or aspenone .
  • verifySSL (optional): Whether to verify SSL certificate sent from server. Default: True.
  • auth (optional): Auth object to pass to the server for authentication. Default: Kerberos-based auth objects that work with Equinor servers. If not connecting to an Equinor server, you may have to create your own auth.

When called with imstype set to pi , list_sources() will search the registry at HKEY_CURRENT_USER\Software\AspenTech\ADSA\Caches\AspenADSA{username} for available PI servers. Similarly, if called with imstype set to ip21 , HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\PISystem\PI-SDK will be searched for available IP.21 servers. Servers found through the registry are normally servers to which the user is authorized, and does not necessarily include all available data sources in the organization.

Example:

from tagreader import list_sources
list_sources("ip21")
list_sources("piwebapi")

When called with imstype set to piwebapi or aspenone , list_sources() will connect to the web server URL and query for the available list of data sources. This list is normally the complete set of data sources available on the server, and does not indicate whether the user is authorized to query the source or not.

When querying Equinor Web API for data sources, list_sources() should require no input argument except imstype="piwebapi" or imstype="aspenone". For non-Equinor servers, url will need to be specified, as may auth and verifySSL .