Data Exchange - WAGO 750-341 Manual

60 • Fieldbus Coupler 750-341

Data Exchange

3.1.5 Data Exchange
The ETHERNET TCP/IP fieldbus coupler can be configured for either
MODBUS/TCP or the Ethernet IP protocol.
MODBUS/TCP works according to the master/slave principle. The master is a
superimposed control unit, i.e. a PC or a PLC device. The ETHERNET
TCP/IP couplers of the WAGO-I/O-SYSTEM are slave devices.
The master makes a query for communication. Through adressing, this query
can be sent to a specific node. The nodes receive the query and return a
response to the master, depending on the kind of query.
A coupler is able to produce a defined number of simultaneous socket
connections to other network subscribers:
•
•
•
The maximum number of simultaneous connections may not be exceeded. If
you wish to establish further connections, terminate an existing connection
first.
For data exchange, the ETHERNET TCP/IP fieldbus coupler uses two main
interfaces:
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•
Data exchange takes place between the fieldbus master and the I/O modules.
One uses as field bus of the MODBUS masters, this accesses over the
MODBUS functions implemented in the coupler data, ETHERNET IP however
used for the data access an object model. The addressing of the data is in each
case different thereby very.
3 connections for HTTP (read HTML pages from the coupler),
5 connections via MODBUS/TCP (read or write input and output data from
the coupler),
128 Ethernet IP connections
interface to the fieldbus (master) and
the interface to the I/O Modules.
WAGO-I/O-SYSTEM 750
ETHERNET TCP/IP