17
Ethernet Setup Notes
Make sure the instrument is connected to an Ethernet port (either part of an existing network or a direct
connection to a PC with a 10Base-T Ethernet card installed). For an existing connection, an RJ-45
straight
through
cable is required. For a direct connection, an RJ-45
crossover
cable is required.
Before Ethernet communications can work, it is necessary to configure the instrument using application
software designed to work with instrument. By default, the Ethernet ability is disabled in the instrument
and must be enabled. If the instrument does not have an assigned IP address and a DHCP (Dynamic Host
Configuration Protocol) server is available on the network, enable the
use DHCP
option. Using DHCP
automatically sets up critical Ethernet parameters using the instrument name. The default instrument name
is the letters “VC” followed by the instrument serial number. The application software should allow the
instrument name to be changed if necessary. (NOTE: Valid names for Ethernet follow strict rules.
Generally, alphanumeric names work best with no special characters). If your network administrator has
assigned a static IP address to the instrument, DHCP may be left unchecked, but then the
IP address
and
Netmask
are required to be entered. The DHCP method is recommended for a quick and temporary
connection. For more permanent installations it is recommended that a permanent IP address be reserved
for the instrument and the instrument should operate in the static mode (DHCP disabled).
If there is a failure to communicate, check the cables and the communication configuration to make sure
they are correct. If the Ethernet has worked previously, but fails to connect, go to the
start/run
entry box
provided by Windows
. Type and run the line: nbtstat –R
Make sure the –R is the capital letter. This utility clears a table that matches names with IP addresses
maintained by Windows
. If there are redundant DHCP servers on the network, it is possible for the
wrong IP address to be assigned to the instrument name. Clearing the table corrects this problem.
Typically, the table updates itself after about 15 minutes, but nbtsat –R clears the table causing an
immediate update when necessary.
