Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 115)

L-force | PLC Designer
Concepts and Base Components
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DMS 4.1 EN 03/2011 TD29 113
A node has separate network addresses for each network connection. Different
network connections may have the same network address, since this address has to be
unique only locally for each network connection.
Terminology: In general, the network address of a node without statement of the
network connection refers to the network address in the main network.
The length of a network address is specified in bits and can be chosen by the block
driver as required. Within a network segment the same length must be used for all
nodes. A network address is represented as an array of bytes with the following
coding:
• Length of the network address: n bits
• Required bytes: b = (n + 7) DIV 8
• The (n MOD 8) lowest-order bits of the first byte and all remaining (n DIV 8) bytes are
used for the network address.
Example - Network address:
Length: 11 Bit
Address 111 1000 1100
Node addresses
The node address indicates the absolute address of a node within a control network
and therefore is unique within the whole “tree”. The address consists of up to 15
address components, each consisting of two bytes. The lower a node is located within
the network hierarchy, the longer is its address.
The node address is comprised of the partial addresses of all predecessors of the node
and the node itself. Each partial address consists of one or several address
components. The length is therefore always a multiple of two. The partial address of a
node is formed from the network address of the node in its main network and the
subnet index of the main network in the parent node. The bits required for the subnet
index are determined by the router of the parent node. Filler bits are inserted between
the subnet index and the network address in order to ensure that the length of the
partial address is a multiple of 2 bytes.