Implementation of EtherNet/IP™
D301271 1013 - FGEN - multi protocol7-2
7.1 EtherNet/IP Communications Profile
EtherNet/IP is based on a connection-oriented communication model. This means that it is only
possible to exchange data via specified connections assigned to the devices.
Communication between the nodes in the EtherNet/IP network can be carried out either via I/O
Messages or Explicit Messages.
7.1.1 I/O Messages
I/O Messages serve to exchange high priority process and application data over the network.
Communication between the slaves in the EtherNet/IP network is carried out according to the Server/
Client Model,
which means a producing application transmits data to another or a number of consuming
applications. It is quite possible that information is passed to a number of Application Objects in a
single device.
7.1.2 Explicit Messages
Explicit Messages are used to transmit low-priority configuration data, general management data or
diagnostic data between two specific devices. This is a point-to-point connection in a Server/Client
System that requires a request from a client always to be confirmed by a response from the server.
Message Router Request
Consists of a service code, path size value, a message router path and service data. An EPATH is used
in the message router path to indicate the target object.
Message Router Response
Consists of a service field with the most significant bit set. This is an echo of the service code in the
request message with the most significant bit set. A reserved byte follows the service code, which is
followed by the General Status code.
7.1.3 Communications profile of FGEN
FGEN behaves as an EtherNet/IP Server in the network; the scanner of the higher-level controller
operates as a EtherNet/IP Client.
The following EtherNet/IP communications types are supported:
Unicast
Multicast
Cyclic Connection
Unconnected (UCMM) Explicit Messaging
Connected Explicit Messaging
Unicast
A point-to-point connection that exists between two nodes only.
Multicast
A packet with a special destination address, which multiple nodes on the network may be willing to
receive.
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