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2.2
Data Exchange Model
2.2.1
Overview
The data exchanged on the CAN subnetwork and the data exchanged on the higher level
network reside in the same internal memory in the Anybus Communicator CAN. In order to
exchange data with the CAN subnetwork, the higher level network simply reads and writes data
to memory locations that have been specified in Anybus Configuration Manager. The same
memory locations can then be exchanged on the CAN subnetwork.
Internal Memory
Input Data
(220 bytes)
CAN Subnetwork
Output Data
(220 bytes)
General Data
Higher Level Network
Fig. 2
Memory buffer structure
The internal memory buffer is divided into three areas based on their function:
Input Data (220 bytes)
This area can be read from by the higher level network.
Output Data (220 bytes)
This area can be written to by the higher level network.
General Data
(up to 1024 bytes)
This area cannot be accessed by the higher level network but can be used for
transfers between individual nodes on the subnetwork, or as a general “scratch
pad” for data.
The size of the General Data area is 1024 bytes. How much of that area that will
be used for communication depends on the configuration.
2.2.2
Memory Map
When building the CAN subnetwork configuration in Anybus Configuration Manager the areas in
the memory buffer will be mapped to the following memory locations:
CAN Network:
Fieldbus:
CAN Network:
Fieldbus:
CAN Network:
Fieldbus:
Write Only
Read Only
Read Only
Write Only
Read/Write
-
Input Data
Output Data
General Data
0x000
0x200
0x0DB
0x2DB
0x400
0x7FF
Fig. 3
Memory Map
The illustration shows the maximum available data areas in Anybus Communicator CAN. The actual
amount of memory that can be allocated depends on the fieldbus network used.
Anybus
®
Communicator
™
CAN PROFINET
®
IRT (2.32) User Manual
SCM-1202-035 1.2 en-US
