VIPA System 200V IM Series, Manual

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Chapter 5 CANopen
Manual VIPA System 200V
5-54 HB97E - IM - Rev. 06/29
IM 253CAN - CANopen slave - PDO
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-Bus coupler IM 253CAN
supports 20 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 10 Tx transmit PDOs for input data and 10 Rx receive PDOs for
output data. The PDOs are named seen from the bus coupler:
Receive PDOs (RxPDOs) are received by the bus coupler and contain
output data.
Transmit PDOs (TxPDOs) are send by the bus coupler and contain input
data.
The assignment of the PDOs to input or output data occurs automatically.
CANopen predefines the first two PDOs in the device profile. The
assignment of the PDOs is fixed in the mapping tables in the object
directory. The mapping tables are the cross-reference between the
application data in the object directory and the sequence in the PDOs.
The assignment of the PDOs, automatically created by the coupler, are
commonly adequate. For special applications, the assignment may be
changed. Herefore you have to configure the mapping tables accordingly.
First, you write a 0 to sub-index 0 (deactivates the current mapping
configuration). Then you insert the wanted application objects into sub-
index 1...8. Finally you parameterize the number of now valid entries in
sub-index 0 and the coupler checks the entries for their consistency.
Note!
The IM 253CAN with DO 24xDC 24V provides only 1 receive PDO, the
PDO mapping is fix.
PDO
Variable PDO
mapping