Fieldbus-Specific Behavior; Canopen; Accessing The Process Image - WAGO -I/O-SYSTEM 750 Series Manual

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Fieldbus-specific behavior

CANopen

4 Fieldbus-specific behavior
4.1 CANopen

4.1.1 Accessing the process image

The CANopen master accesses the AS-Interface mailbox and process data in
the coupler / controller with process data objects (PDO).
In the default configuration, the data for the AS-Interface master module are
mapped in consecutive PDOs. Each PDO can hold eight bytes of data. The
maximum process image of the AS-Interface master of 48 bytes therefore
includes six PDOs.
PDO for status-/control-
byte and mailbox or
cyclical data
Fig. 4-1: PDO assignment, AS-Interface master module
The first PDO, which is assigned to an AS-Interface master module, contains
the status / control byte, one empty byte and up to six bytes of mailbox or
process data. The subsequent PDOs contain AS-Interface process data.
Note:
When using a CANopen coupler / controller, the maximum mailbox size is
limited to six bytes.
1
PDO for cyclical data
PDO for cyclical data
PDO for cyclical data
Process image
AS-interface - master
1 8
C Mailbox
...
/
data
S
acyclical
8
1 8
1 8
1
PDO for cyclical data
PDO for cyclical data
12-48
...
Process data
cyclical
8
1 8
1 8
WAGO-I/O-SYSTEM 750
I/O Modules
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