Configuration software address assignment
When the TCP/IP address is set with the aid of the KS2000 configuration software, the
software sets the first three bytes of the IP address. The DIP switch configures the
“low” byte on the BK9000 or the BC9000. This means that devices in the subnet
can all receive the same “basic setting”, and are subsequently differentiated
from one another – as is usual with fieldbus devices – merely by the setting of
the DIP switch.
Address assignment by DHCP server
Assignment by a DHCP server (Domain Host Control Protocol) is made through a table in the
server software. To do this, it is necessary to know the MAC-ID of the Ethernet node, and
enter it at the server. Usually, the DHCP server dynamically assigns IP addresses. This
means that Ethernet nodes may have a different IP address after a period of time, or after
a restart. Because the application software does not automatically detect dynamic IP
assignment, it is possible under some circumstances for data to be received from the wrong
node, or sent to the wrong node. Dynamic assignment is, for this reason, not helpful. The
relationship between the MAC-ID and the IP addresses in the DHCP server should be fixed.
Since the MAC-ID of Beckhoff Bus Couplers is pre-set, it is possible to set the IP address
without additional tools.
Address assignment by BOOTP server
A BOOTP server is comparable to a DHCP server. Under BOOTP there is also a form of table
in which the association between the MAC-ID and the IP address is specified. BOOTP is,
however, not able to assign addresses dynamically. The BOOTP server offered by Beckhoff
performs the association of the MAC-ID and the IP address. The BOOTP is configured in such
a way that only the Ethernet nodes of Beckhoff devices are detected automatically. This
ensures that only these IP addresses, not those of other devices on the network, are
passed on to the application. The MAC-ID is automatically displayed to the user as soon as
the nodes are connected to the network. This means that if each node is brought into
operation individually, the BOOTP server no longer has to know the MAC-ID. The first time
it is started up and receives its IP address, the Ethernet device can store the address
permanently, or it can request it again at a later start-up. The assignment of the IP
address takes between one and 10 seconds, after which it is immediately valid. The BOOTP
server from Beckhoff can run under Windows 98/ME/NT4.0/2000/XP.
Address assignment by ARP message
In the “ARP” method, the MAC-ID of the Ethernet device must be known. The new IP
address is transmitted to the Ethernet nodes with arp –s (Set) and the MAC-ID. The
new IP address is then immediately valid, and remains stored in EEPROM. All that is
necessary for this method is the command line interface of any operating system –
special software tools are not required.
A new firmware and the libraries can be found on the Internet at www.beckhoff.com
