Technical Manual – IP Router SCN-IP100.03
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The assignment of the IP address of the device can be done either manually or by a DHCP server, this
is often available in DSL routers.
When selecting “DHCP - do not use”, the IP configuration can be set manually.
When selecting "DHCP – use”, a DHCP server must assign a valid IP address to the KNX / IP router. If
there is no DHCP server available, the router restarts after a certain waiting period with an AutoIP
address (address range of 169.254.1.0 to 169.254.254.255). Once a DHCP server is available, it
automatically assigns a new IP address to the device.
IP-address
The IP address must be allocated so that the bytes 1-3 are the same as those of the communicating
computers. So the membership is given on the network. The 4th byte must be any available IP
address (0-255) on the network, so as to avoid addressing conflicts.
The subnet mask is used for the device to determine whether a communication partner is located in
the local network. Should not be a partner in the local network, the device does not send the
telegrams directly to the partner but to the gateway, which handles the routing.
The setting of the gateway makes it possible for networks, which are based on different protocols to
communicate with each other.
Note: If the KNX IP Interface is only be used in the local LAN, the entry can remain 0.0.0.0.
The network settings of the communicating computers can be read in the network settings of the PC.
4.3 Example of assigning IP addresses
A KNX IP interface to be accessed via PC. The PC has the following IP settings:
IP address of the PC:
192.168.1.30
Subnet of the PC:
255.255.255.0
Is the KNX IP Router located in the same local LAN, i.e. it uses the same subnet, the assignment of the
IP address is restricted by the subnet. That means in this example the IP address of the IP Router has
to be 192.168.1.xx. xx can be a number from 1 to 254 (with the exception of 30, which has already
been used). It must be ensured, no numbers are assigned twice. The following settings can therefore
be made in the IP Interface:
IP address of the IP Router:
192.168.1.31
Subnet of the IP Router:
255.255.255.0