Use global I/O addresses

Global addresses to I/O data allow all View nodes to share a common network-based I/O Server. This eliminates the need for multiple I/O Servers, but is less fault-tolerant and can result in lower overall performance.

In the following figure, two View nodes are running a copy of the same application. Both View nodes refer to the same I/O data source. Because each application uses a fully qualified I/O address for the data source, all references point to the same I/O Server.

You can set up an InTouch application to identify an element of data stored on another node by using a three-part addressing convention in an Access Name. The Access Name addressing convention includes the node name, application name, and topic name where the remote data is located. An InTouch application obtains remote data using the Access Name in combination with an item name. For more information about defining an Access Name for a remote I/O Server, see Data access with I/O in AVEVA™ InTouch HMI Application Development.

Note: When you create Access Names in WindowMaker, if the Access Name uses the SuiteLink protocol, the software prevents Access Names from accessing the same node, application and topic. Do not use the IOSetAccessName() function to redirect Access Names to duplicate ones during run time or else the redirected Access Name will not work.