Licensing and the OMI web client

AVEVA System Platform licensing controls which products your installation has access to and the number of users who can access them. This topic describes how licensing works with the OMI web client.

Each deployed WebViewEngine consumes one license. This allows an unlimited number of users to run OMI ViewApps deployed on that WebViewEngine. Each user has read/write access in each ViewApp they use. The process of acquiring and renewing the license is as follows:

1. When a WebViewEngine is deployed, it tries to connect to the License Server to acquire a license.

2. Whether it acquired a license or not, it continues to try to connect to the License Server periodically, either to acquire a license or to refresh the license that it has.

3. As long as the WebViewEngine succeeds in acquiring and refreshing its license, all ViewApps deployed to it continue to function normally.

4. If the WebViewEngine fails to acquire or renew a license--for example, if it cannot connect to the License Server--a two-hour countdown begins. During this countdown period:

   • Users can continue to use any open ViewApp deployed on the WebViewEngine. ViewApps will continue to function as normal, with no change in functionality.

   • Users will not see any message or other indication anywhere in the web client that the ViewApp does not have a license.

   • The WebViewEngine continues to try to acquire a license periodically.

   • A warning message is sent to the logger every fifteen minutes about the failure to acquire a license and saying that the OMI web client is in demo mode.

If the WebViewEngine acquires a license before the two-hour period is over, ViewApps return to normal operation. Users will not have seen any difference in operation.

If the WebViewEngine does not acquire a license within the two-hour period, it stops processing new requests for either data or content. This means:

• Any open ViewApp will not receive any new data from external references (User-Defined Attributes).

• Users will not be able to write to any external references. Writes to custom properties and ViewApp namespaces will continue to work.

• Users will see an error message and the action will fail if they try to access the web client home page, open any other ViewApp, or refresh the page of an open ViewApp. The exact error message varies.

• The warning messages sent to the logger change to say that demo mode has expired.

The WebViewEngine continues to try to acquire a license after demo mode has expired. If it is able to contact the license server and acquire one, it resumes normal operation.

Note: If you redeploy the WebViewEngine during or after the demo period, and it cannot acquire a license, it restarts the two-hour demo mode period. For uninterrupted service, you should ensure that the License Server always has enough valid licenses for all deployed WebViewEngines.