Browsing Tree

The address space can be browsed online.

The address space on OPC Classic and OPCPipe starts in the root.

Example: <PLC>.flag0. Or "System.Topics.<PLC>.Status

On OPC UA the root starts with "Objects". Under this topic there are multiple elements depending on the OPC configuration. The most important element is the element "Topics". All elements described on this manual are under this item.

Example: Objects.Topics.<PLC>.flag0. Or "Objects.Topics.System.Topics.<PLC>.Status

If browsing of items is not used registering an item needs a prefix. Which prefix your OPC UA server requires can be found in the documentation of your OPC UA server. No standard for a prefix exist, some servers are using names, others UUID or numbers, but it can be a binary field also. There exist no limitation in length. It is not guaranteed that the prefix will be the same after reconnect to the UA server.

The OPC UA server needs if browsing will not be used "#ns=1;s=" in front of an item. Leave the "Objects.Topics" away.

Example the OPC UA server: Read the flag word zero from a Siemens S7 300, the OPC connection is named "OPC", the controller connection is named "s7": "OPC.#ns=1;s=s7.mw0"