238 • LON

Network installation

5.4 Network installation

A node initially network-neutral, obtains its identity only at the time of installation. Three tasks are necessary during installation:

•Address assignment

•Configuration

•Binding

During the installation process a network database (Database) is created in which all network information is saved or from which such information can be taken. Once the installation is completed, the database receives a copy of the network configuration including all node names, the network variables of all nodes, the addresses, the time generator adjustments and all connections produced during binding. In this manner defective nodes can be easily exchanged by new nodes and the communication continued quasi without interruption. All network parameters and also the application specific parameters are available and only need to be written into the new node. This can be performed directly via the network.

5.4.1 Addressing

The Neuron ID is used by the WAGO TOPLON® Software for the unique and unmistakable identification of the nodes.

When pressing the Service Pin key (SRQ) at the begin of the network configuration a node is identified to all nodes in a network by means of the coupler inherent ID.

For programming own Neuron-C applications, the assignment of a logical address proves one's usefulness. This logical node address can be assigned using the two coding switches. If it is nessassary to replace one node by a new one, the new node will receive the logical address of the failed one although its Neuron ID is certainly different from that of the previous node. No changes have to be made to the logic overall network structure.

Addressing the Lonworks technology has a 3-level hierarchy.

•Domain (area) represents the logical separation of the networks which physically share one transmission medium (channel).

•Subnet (partial network) logically groups network nodes which are located on one channel or on channels interconnected by means of bridges.

•Nodes as physical components.

The maximum number of subscribers in a domain is limited to 32.385 for the possible addressing of 255 subnets per domain and 127 nodes per subnet.

Addressing is not influenced by the transmission medium. As such, a domain can contain one or also several channels. The subnet and node addressing is possible beyond the channel boundaries.

Modular I/O System

LONWORKS®

LON • 239

Network installation

5.4.2 Configuration

During configuration the network-specific and application relevant parameters of a node are activated in order to set it for a certain network and a specific application. Network-specific parameters are, for instance, the node priority or the decision about the utilisation of a data transmission service. Set point values or calibration values are application specific parameters. A node is configured either by a pre-configured file from the data base or with the aid of a network management tool.

5.4.3 Binding

The so-called binding is the linking process of a node with other nodes in the network. This interlinking is physically achieved by the transmission of a network management message containing the required address information to a node to be integrated.

The following chapter: "Network communication" contains an example which illustrates the binding between two nodes.

Modular I/O System

LONWORKS®