Snapshot state and related properties

The previous version of the QRC demo project, the "Color" property of the Load button was used to recognize the snapshot state. This is an unofficial "workaround" but it is still working well. Now, a new way has been implemented. The "Color" functionality still remaines.

Since the version 1.1.0.0, the function block FB_QRC_Snapshot can now be used to load or save a snapshot directly, and to query multiple snapshots manually. With the help of method AddSnapshotControl of the function block FB_QRC_ChangeGroup multiple snapshots can be joined in a change group. Afterwards their states can be polled cyclically. The function block FB_QRC_ResExtract has also been updated in order to extract the response frame of a snapshot.

A Snapshot Bank consists of a Snapshot Controller, and all the controls and components you add to it. This Snapshot Controller is also a component control and is called "snapshot component" in the following documentation for a better understanding.

Within a snapshot component, each snapshot has two related properties/component controls, which are listed below:

• last.x: It describes whether the snapshot is loaded or not.
• match.x: It describes whether Controls within the snapshot have been changed after this snapshot was loaded.

These two property names can be found using the menu "View Component Control Info..." in Q-SYS Designer. With the help of these two properties, the snapshot state can be determined.

"last" and "match" property value and their corresponding snapshot state are listed below.

This logic has been implemented in the function block FB_QRC_ResExtract and the method AddSnapshotControl and GetSnapshotState.