WAGO 750-341, Руководство пользователя

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50 • Fieldbus Coupler
Fieldbus Coupler 750-341
WAGO-I/O-SYSTEM 750
ETHERNET TCP/IP
3.1.4.3 Process Data Architecture
With some I/O modules, the structure of the process data is fieldbus specific.
In the case of an Ethernet TCP/IP coupler/controller, the process image uses a
word structure (with word alignment). The internal mapping method for data
greater than one byte conforms to the Intel format.
More Information
You can find the fieldbus specific process data architecture for all I/O
Modules of the WAGO-I/O-SYSTEM 750 and 753 in the chapter „Process
Data Architecture“.
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:
•
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
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:
•
interface to the fieldbus (master) and
•
the interface to the I/O Modules.
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