Ethernet; Network-Addresses, Network-Connections; Tcp-Connection Setup; Data Exchange - DEUTSCHMANN AUTOMATION UNIGATE CL-Fast Ethernet Instruction Manual

Deutschmann Automation GmbH & Co. KG

14 Ethernet

Each Ethernet-Client processor with TCP/IP network-protocol in a 10/100 Mbaud Ethernet can
exchange data with the Gateway.

14.1 Network-addresses, network-connections

After switching on, the Gateway is waiting for data communication with a network-participant. In
this case the Gateway is always prepared to react to ICMP messages (e. g. PING Request and
Reply). The functions of the ARP-protocol are also available.

14.2 TCP-connection setup

In the characteristic application in the TCP/IP-protocol, after switching on, the Gateway is in the
state "Passive Open" under an IP-address and port number that was determined in the configu-
ration. A Client processor is in the position to open a TCP/IP connection with the Gateway under
the port determined in the configuration. After a successful connecting, data can be exchanged.

14.3 Data exchange

At the protocol TCP/IP, a full duplex data connection is available after establishing a connection
between the Gateway and the attached Ethernet-Client. The data stream is protected by the
TCPI/IP-protocol in both directions.
When operating with UDP/IP-protocol, no connection is established before data is transferred. In
this case the application is responsible for the control of the data flow as well as for the backup of
the data.

14.3.1 TCP or UDP?

TCP is a connection-oriented protocol: Here a fixed logical connection between Client and
Server exists in the course of the data communication. TCP features all mechanisms, that are
required, in order to open a connection and to guarantee a flawless data transfer across the net-
work and then again close the connection. For that reason the protocol software creates and
administers own buffers for each connection. In case a lot of UNIGATE
addressed from one processor at the same time, storage limits in the processor might result in an
extreme case.
In contrast to TCP, UDP does not have mechanisms available to repeat data packets or to check
them on their completeness. The data communication with UDP is to be recommended if a
parent protocol guarantees a flawless transmission between the terminal device at the
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UNIGATE -server and the application on the TCP/IP-station anyhow.

14.4 Data exchange mode

The Gateway has to be in the data exchange mode, so that a data exchange between the
RS-side of the Gateway and the fieldbus is possible. As long as the Gateway is not in the config-
uration mode or the test mode, the data exchange mode is active. In the data exchange mode
the Gateway will carry out the Script with those parameters preset through WINGATE and in the
Script.
There are 4 communication channels.
For the channels the following adjustments in the Script in each case have to be made:
21.6.18 UNIGATE Fieldbus Gateway UNIGATE
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-servers are to be
CL - Fast Ethernet V. 2.6
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Ethernet
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