Setting the IP address using the ARP table

An easy method of modifying the IP address is to set the address using the DOS window. It is, however, only possible to alter addresses within the same network class. The new IP address that has been set remains stored even after the Bus Coupler has been switched off.

Procedure

• Set DIP switches 9 and 10 to OFF. DIP switches 1-8 then no longer have any address function.
• Open a DOS box on your PC.
• Enter the command "ping <OLD IP address>" to create an entry in the ARP table.
• Read the table with the command "ARP -a".
• Enter "ARP -d <OLD IP address>" to remove the Bus Coupler from the table.
• Use "ARP -s <NEW IP address> <MAC-ID>" to make an entry manually.
• With "ping -l 123 <NEW IP address>" the new IP address becomes valid.

A short flash from the ERROR LED at the moment of switching on indicates that the Bus Coupler is being addressed by ARP, and that DIP switches 1-8 give no indication of the address that is set.

Changing the IP address If the IP address is changed, all dynamic ARP entries must be deleted. Only one ping with a length of 123 bytes is permitted for the reconfiguration of the IP address (>ping -l "IP-Address<).

Sample

1. C:>ping 172.16.17.255
2. C:>ARP -a
   172.16.17.255       00-01-05-00-11-22
3. C:>arp -d 172.16.17.255
4. C:>arp -s 172.16.44.44 00-01-05-00-11-22
5. C:>ping -l 123 172.16.44.44