Configure advanced communication management

Advanced Communications Management minimizes network traffic and CPU usage of a DI Object and DAServer when a particular DI attribute is currently subscribed to, but its value is not currently shown. For example, scanning for updated values from a DI attribute representing pump RPM is suspended when an operator minimizes the application window containing a pump graphic containing attribute references that subscribe to the DI object’s pump RPM attributes.

Note: This dependence on the attribute being referenced by a running application is only the case when the attribute subscription is not already active due to configuration for history, alarming, or scripting. For example, if an attribute is configured for history, the subscription to the field device will always be active regardless of what window is active in InTouch, and regardless of whether InTouch is running at all.

When the items on the current window are no longer active because the window is minimized, a Suspend operation is performed for each item. Suspending scanning causes data updates to stop flowing to the application without deleting the subscriptions for each item. This reduces the overhead of unsubscribing and subscribing again to items when windows are minimized and restored.

In Advanced Communication Management, applications monitor the number of outstanding references to attributes that are updated with values from an external source object. When an attribute’s external reference count reaches zero, the application sends a Suspend message to the source object requesting it to suspend updates. For example, a UserDefined object named PumpRPM has an attribute named RPM, which has an integer data type. The input source of RPM is plc1.n7:11, where plc1 is an ABPLC DI object.

When there are no active subscriptions to ud1.RPM, the subscription between input source and PumpRPM is suspended. When a client like ObjectViewer or a managed application running in WindowViewer subscribes to ud1.RPM, an Activate message is sent to the DI object to start sending data between the plc1 object and the PumpRPM object. This enables ObjectViewer or a managed client application running in WindowViewer to receive current plc1 data.

Unlike defined static attributes, some scan groups contain dynamic attributes. Dynamic attributes within a scan group provide the means for a running application’s objects to dynamically subscribe to data from an external device. Dynamic attributes are created, activated and added to the scan group using ApplicationObject attributes or InTouch indirect tags and scripts that include the IOSetRemoteReferences function.

When a dynamic attribute is poked, the time stamp is updated to the timestamp passed in with the value if available, or the current time provided by the hosting AppEngine is used. If the data provider passes in a Value, Time, Quality (VTQ) triplet of data in the callback, the time stamp is associated with the value and quality used to update the attribute.

To enable Advanced Communication Management, you must:

• Select Advanced Communication Management for your Galaxy.

• Set the scan mode for each scan group that belongs to your device integration objects within the Galaxy.