ProSoft Technology MVI56-GEC - Manual (Page 83)

MVI56-GEC ♦ ControlLogix Platform Reference
Generic ASCII Ethernet Communication Module User Manual
ProSoft Technology, Inc. Page 83 of 108
October 8, 2010
Each server on the module is assigned its own server port number. This does not
mean that two or more servers cannot share the same port number. In fact this
might be desirable in some instances. It is up to the ladder logic to keep track of
each message and to insure that a request/response transaction is associated
with the correct connection. Information to keep track of each connection is
passed in each input image. The status data set provides the IP address and
TCP port address for the connection on each server. Each message transferred
between the module and the processor has a server index word. This word
associates the message with a server, which is associated with a connection to a
specific IP address and TCP port address. Therefore, each connection is
specified to the processor by the server index. The following illustration shows a
snapshot of the modules status data:
Server Status Data Description of Server
Server 0 IP of Host (192.168.0.100) This server is connected (State=1) to IP address
192.168.0.100 on TCP port 1243.
Port of Host (1243)
State = 1
Server 1 IP of Host (192.168.0.100) This server is connected (State=1) to IP address
192.168.0.100 on TCP port 1244.
Port of Host (1244)
State = 1
Server 2 IP of Host (192.168.0.101) This server is connected (State=1) to IP address
192.168.0.101 on TCP port 56443.
Port of Host (56443)
State = 1
Server 3 IP of Host (192.168.0.102) This server is connected (State=1) to IP address
192.168.0.102 on TCP port 7943.
Port of Host (7943)
State = 1
Server 4 IP of Host (0.0.0.0) This server is not connected (State not equal to 1)
and is waiting for a connection.
Port of Host (0)
State = 0
Ladder logic can send messages to the clients connected to servers 0 to 3.
Messages sent to server 4 will not be sent from the module because there is no
connection active on that server.