750-841 WAGO, 750-841 Datasheet - Page 58

• Manufacturer Part Number: 750-841
• Description: CONTR.ETHERNET TCP/IP 10/100MBIT
• Manufacturer: WAGO

Specifications of 750-841

• Rohs Compliant: YES
• No. Of Digital Inputs: 10
• No. Of Digital Outputs: 10

50 •
3.1.5 Process Image
3.1.5.1 General Structure
Fieldbus Controller 750-841
Process Image
The powered-up controller recognizes all I/O modules connected in the node
that are waiting to transmit or receive data (data width/bit width > 0). The
maximal length of a node is limited to 64 I/O modules.
The controller generates an internal local process image from the data width
and type of I/O modules, as well as the position of the I/O modules in the
node. This image is divided into an input and an output area.
The data of the digital I/O modules are bit-based (i.e., the data exchange is
made by bits). The analog I/O and most specialty modules (e.g., counter
modules, encoder modules, and communication modules) are byte-based, in
which the data exchange is made by bytes.
The process image is divided into an input and an output data area. Each I/O
module is assigned a location in the process image, based on the data
exchange type (i.e., bit-based or byte-based) and their position after the
controller.
All of the byte-based I/O modules are filled in the process image first, then the
bit-based modules. The bits of the digital modules are grouped into a word.
Once the number of digital I/Os exceeds 16 bits, the controller automatically
starts another word.
The process image for physical input and output data is stored in the first 256
words of memory (word 0 to 255). This memory actually consists of a
separate area for the input and output data, but both areas are referenced in a
PLC program with an index of 0 to 255 for word operations.
Note
Use of the WAGO 750-628 Bus Extension Coupler Module and the 750-627
Extension End Module enables support of up to 250 I/O modules on the
750-841 controller.
Note!
Expansion to 250 I/O modules is enabled in the controllers with software
version ≥ SW 9.
Note
For the number of input and output bits or words of an individual I/O module,
please refer to the corresponding module description later in this chapter.
Note
Changing the physical layout of a node will result in a new structure of the
process image. Also, the addresses of the process data will change. When
adding or removing modules, the process data must be verified.
WAGO-I/O-SYSTEM 750
ETHERNET TCP/IP