PI Web API subscriber resources

The PI Web API subscriber resources specify the tag configuration for monitoring changes on a PI Web API server. When used in the PI Web API Subscriber module, these resources set up a subscription for each listed tag. All changes in the specified tags are received as messages from PI Server.

Code example: Aveva PI resource

"dataServers":

{

"webId": "F1DSA_IIvCccC0KbowWzAt8ruAMTAuMC4wLjI",

"name": "Factory1",

"items": [

{

"name": "BA:LEVEL.1",

"webId": "F1DPA_IIvCccC0KbowWzAt8ruABwAAAAMTAuMC4wLjJcQkE6TEVWRUwuMQ",

"metaData": { "foo": "bar" }

},

{

"name": "BA:CONC.1",

> "webId": "F1DPA_IIvCccC0KbowWzAt8ruACAAAAAMTAuMC4wLjJcQkE6Q09OQy4x",

"metaData": { "foo": "baz" }

}

]

> }

]

}

A JSON file defines the configuration for each tag to be subscribed to.

Note: While webId for each dataServer and tag is optional, it is recommended to include it for optimized performance, as omitting webId can significantly slow down the subscription setup.

How to reference PI Web API Subscriber resources

The resource file supports configuring multiple data servers, with each server containing its own list of tags. This approach allows for efficient data retrieval across multiple servers within a single configuration file.

In this resource file, dataServers represent PI data servers; each one is defined as a JSON object. Each data server must include a name and at least one tag in the items list. The webId of the data server is optional but recommended to improve performance. Custom metadata can be added to each item object, which will appear in the outgoing messages.

Each tag (or item) has the following parameters:

• name: The unique identifier for the tag, required for every tag.

• webId: An optional, unique identifier within PI for efficient lookup; including the webId improves performance.

• metaData: The optional custom metadata associated with the tag. This metadata is added to the outgoing message to provide additional context.

This resource format allows for a configuration of multiple data servers, each with their own tags, to subscribe to updates across a network of PI servers.