Filter
Top Products
186
Communications Testing Functions Section 9-1
9-1 Communications Testing Functions
The Ethernet Unit provides two functions that allow communications with
other node to be tested.
PING Command The PING command is a common way to perform echoback tests on Ethernet
networks. The PING command can be executed to see if nodes are physically
connected properly and to be sure that IP address are set for the correct
Ethernet nodes.
Internode Testing Echoback tests with specific nodes can also be performed by setting parame-
ters in the DM Area and then manipulating specific bits in memory. This type
of internode test can be performed only for remote nodes that support the
FINS internode testing function. Internode testing can be used to make sure
settings for FINS communications services are correct.
9-2 PING Command
The PING command sends an echo request packet to a remote node and
receives an echo response packet to confirm that the remote node is commu-
nicating correctly. The PING command uses the ICMP echo request and
responses. The echo response packet is automatically returned by the ICMP.
The PING command is normally used to check the connections of remote
nodes when configuring a network. The Ethernet Unit supports both the ICMP
echo request and reply functions.
If the remote node returns a normal response to the PING command, then the
nodes are physically connected correctly and Ethernet node settings are cor-
rect.
9-2-1 Ethernet Unit
The Ethernet Unit automatically returns the echo response packet in
response to an echo request packet sent by another node (host computer or
other Ethernet Unit). An echo request packet can be sent to another node by
issuing the FINS command to execute the PING command from the PC. Refer
to page 236 for details on the PING command.
9-2-2 Host Computer
The PING command can be executed from the host computer to send an
echo request packet to an Ethernet Unit. The method for using the PING com-
mand from a UNIX computer is given next.
TCP UDP
ICMP
IP
Ethernet
Echo request
Echo response
Remote Node
(host computer or Ethernet Unit)
Ethernet Unit
PC