PI Web Service and Trend

The PI Service is a web service which acts as a single point of access to PI data. Both people and application programs can retrieve PI data using the same simple web requests. From a security and manageability standpoint, only a webserver needs to access the historian directly, allowing the firewall to be dramatically locked down to protect the historian from attack by compromised user machines.

The PI Web Service allows speedy access to current and archived data and can be permissioned to allow writing data down to the historian. Various sample methods can be utilised such as raw, average or standard deviation and a wildcard tag search facility is provided. No client-side software needs to be deployed, beyond the standard Internet Explorer browser.

The PI Trend is a separate component that works with the PI Service. It provides a high-speed, smoothly scrollable trend in the form of a web page. The user can interact with the trend, changing ranges, timebase and sample methods, as well as adding tags with a built-in search facility

All aspects of the trend can be specified on the URL, (tags, axes, etc) making it ideal for embedding in web pages or Sharepoint systems. When used in an iframe, it also exposes an API which allows developers to programmatically interact with the trend