WAGO 750-341, Руководство пользователя

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52 • Fieldbus Coupler
Fieldbus Coupler 750-341
WAGO-I/O-SYSTEM 750
ETHERNET TCP/IP
3.1.5.2 Addressing the I/O modules
The arrangement of the I/O modules in a node is optional.
When addressing, first of all the more complex modules (modules occupying 1
or more bytes) are taken into account in accordance with their physical order
behind the fieldbus coupler. As such, they occupy the addresses starting with
word 0.
Following this, the data of the other modules (modules occupying less than 1
byte) follow, grouped into bytes. In accordance with the physical byte-wise
order this data is used to fill up the bytes. As soon as a full byte is occupied by
the bit-oriented modules, the next byte is automatically started.
Attention
For the number of input and output bits and/or bytes of the individual activated
bus modules, please refer to the pertaining descriptions of the bus modules.
Attention
Once a node is modified, a new architecture of the process image can result. As
such, the address of the process data will alsochange. In the event of adding
modules, the process data of all previous modules has to be taken into account.
Data width
≥
1 Word / channel Data width = 1 Bit / channel
Analog input modules Digital input modules
Analog output modules Digital output modules
Input modules for thermal elements Digital output modules with diagnosis (2 Bit / channel)
Input modules for resistance sensors Power supply modules with fuse holder / diagnosis
Pulse width output modules Solid State power relay
Interface module Relay output modules
Up/down counter
I/O modules for angle and path measurement
Table 3.1.1: I/O module data width
3.1.5.3 Data exchange between MODBUS/TCP master and I/O modules
The data exchange between the MODBUS/TCP master and the I/O modules is
made by the implemented MODBUS functions in the coupler with reading and
writing in bits or bytes.
The coupler handles four different types of process data:
•
Input words
•
Output words
•
Input bits
•
Output bits
The word for word access to the digital input and output modules is made in
accordance with the following table: