VIPA CPU 21 Series, Руководство пользователя

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Manual VIPA CPU 21x Chapter 8 Deployment CPU 21xCAN
HB103E - Rev. 05/45 8-17
A CANopen device can be structured as follows:
Communication
Status machine
SDO
PDO
PDO
SYNC
NMT
Heartbeat or
Node Guarding
SDO
Status machine
Application
Object
Object directory
Index Subind. Value
entry 1
entry 2
entry 3
.
.
.
entry n
Application
Application
Object
Application
Object
Application
Object
Application
Object
P
ro
c
e
s
s (
I/
O
s)
CA
N b
u
s
s
y
s
te
m
.
.
.
Communication
Serves the communication data objects and the concerning functionality for
data transfer via the CANopen network.
Application
The application data objects contain e.g. in- and output data. In case of an
error, an application status machine switches the outputs in a secure state.
The object directory is organized as 2 dimension table. The data is addres-
sed via index and sub-index.
Object directory
This object directory contains all data objects (application data +
parameters) that are accessible and that influence the behavior of
communication, application and status machines.
In many fieldbus systems the whole process image is transferred - mostly
more or less cyclically. CANopen is not limited to this communication
principle, for CAN supports more possibilities through multi master bus
access coordination.
CANopen divides the process data into segments of max. 8Byte. These
segments are called
p rocess d ata o bjects (PDOs). Every PDO represents
one CAN telegram and is identified and prioritized via its specific CAN
identifier.
For the exchange of process data, the VIPA CAN-Master supports 80
PDOs. Every PDO consists of a maximum of 8 data bytes. The transfer of
PDOs is not verified by means of acknowledgments since the CAN protocol
guarantees the transfer.
There are 40 Tx transmit PDOs for input data and 40 Rx receive PDOs for
output data. The PDOs are named seen from the CAN-Master:
Receive PDOs (RxPDOs) are received by the CAN-Master and contain
input data.
Transmit PDOs (TxPDOs) are send by the CAN-Master and contain output
data.
The assignment of the PDOs to input or output data occurs via WinCoCT
automatically.
Structure of the
device model
PDO