Managing dynamic objects

Dynamic objects are BACnet objects that can be created during runtime (RUN or Free RUN) on a server (local) or a client (remote) without having to reactivate/restart TwinCAT. Dynamic objects of a local server are accessed via the Settings tab of the BACnet server. In the Settings tab the dynamic objects can be displayed, created or deleted. In addition, the Scan button can be used to scan existing objects that are not displayed and integrate them into the tree diagram under the server (e.g. dynamic objects that were generated by a remote system). To create an object the corresponding Object Typeand an Instance ID (object number) have to be entered. To delete, enter an existing object number with associated object type, or conveniently select it with the button "Dynamic Objects".

The procedure for accessing the dynamic objects of a client (remote access) is similar. The management function can be found in the Settings tab of the associated BACnet client. The difference in the management of a server is in the distinction between dynamic and static (configured offline) objects. In general all dynamic objects can be created/deleted, except loop, device and program objects. Static objects can neither be created nor deleted at runtime. However, since the BACnet communication makes no distinction between dynamic and static objects, there is no difference in how the objects are displayed in the tab "Settings" → "View Objects" of the BACnet client. The "Online Objects" dialog therefore lists all objects that the client side makes available. An attempt to delete a static object is acknowledged with fault feedback from the BACnet client (error result). The Settings tab of the BACnet client offers an option to create several dynamic objects simultaneously. To this end press the shortcut CTRL+SHIFT when pressing the Create button.

Dynamic objects are indicated with a green symbol under a BACnet server. Due to the client behavior mentioned above, on the client side there is no distinction in the tree view.

During the dynamic creation of client objects the user can specify whether or not an object ID has to be specified in the CreateObject service. It should be noted that the devices from some manufacturers only support dynamic object creation without specification of an object ID. In this case the "Instance ID" option can be deselected.

Since dynamic objects are only created at runtime, there is no process data mapping option. The linking of process data must be known during loading of the TwinCAT configuration. This in turn precludes offline configuration of dynamic objects. The configuration therefore always takes place under the Online tab. Please note that the configuration of all dynamic objects and their properties is only retained after a restart if data persistence is activated (for information on data persistence please refer to chapter "Persistent data").