Fluke NetDAQ 2645A - Manual (Page 279)

Network Considerations
Troubleshooting Information
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NetDAQ instrument and the PC default gateway addresses to make sure they
are set correctly.
Check all network wiring. Make sure that 10Base2 terminators are placed at
the two open ends of the coax. Make sure that there is no more than one
terminator on each end (some network repeaters, bridges, and routers have
termination built into the unit.)
In a 10Base2 network, make sure that the collision indicator on the
instruments (amber LED) is not lighting. If the collision indicator lights often,
check all wiring for possible sources of impedance mismatch, missing
terminators, broken insulation, metal parts touching each other (i.e. the Tee
touching another connector on the PC), or other wiring problems.
In a 10BaseT network, make sure that the link indicator (same amber LED) is
lit continuously. If it is not, make sure that connection to the hub is correct
and that the hub port is active.
If you have replaced an instrument with another with the same IP address
(same BCN in the isolated network mode), you must reboot your PC. The
TCP/IP software builds a table of the relationship between an instrument’s IP
address and its Ethernet address. If you attach a new instrument to the network
with an IP address that has been previously used, the relationship between the
IP and Ethernet address will be wrong, causing communication with that
instrument to fail. Rebooting the PC clears the IP/Ethernet address
relationship table (the ARP table).
Make sure that there is only one TCP/IP stack software package running on
this PC.
4. Instrument to PC communication starts OK, but there are frequent
communication interruptions reported.
On a general network that is heavily loaded or if there are lots of routers or
gateways between the host and the instrument, the communication time-out
value may need to be increased. Edit the CommTimeout parameter in the
netdaq.ini file (value is seconds) to increase the timeout up to 1000
seconds.
There may be times on a very heavily loaded general network where it is
impossible to maintain high enough speed communication with the instrument
to avoid communication interruptions. In this case, consider moving the
instrument to an isolated network or a different subnet.
5. NetDAQ Logger can not keep up with the scan rate selected in the
instruments. This is indicated by the count of the number of scans in the
instrument increasing continually, to the maximum count, during a data
acquisition run. Once the maximum count is reached, an error message is
displayed by the NetDAQ Logger software indicating that scans are being lost.