I/O Modules • 177
Process Data Architecture for CANopen
WAGO-I/O-SYSTEM 750
CANopen
The following table shows the assignment of the process image size to the
number of occupied PDOs when the mailbox is permanently superimposed
(Mode 1).
Input and Output Process Image
process
image size
12 byte
20 byte
24 byte
32 byte
40 byte
48 byte
n-th PDO
1 status/
control byte
1 empty byte
6 byte
mailbox
1 status/
control byte
1 empty byte
6 byte
mailbox
1 status/
control byte
1 empty byte
6 byte
mailbox
1 status/
control byte
1 empty byte
6 byte
mailbox
1 status/
control byte
1 empty byte
6 byte
mailbox
1 status/
control byte
1 empty
byte
6 byte
mailbox
n+1-th
PDO
4 byte prozess
data
(flags and
slave 1/1A -
slave 7/7A)
4 byte empty
(reserved)
8 byte prozess
data
(flags and
slave 1/1A –
sl. 15/15A)
8 byte prozess
data
(flags and
slave 1/1A –
sl. 15/15A)
8 byte prozess
data
(flags and
slave 1/1A –
sl. 15/15A)
8 byte prozess
data
(flags and
slave 1/1A –
sl. 15/15A)
8 byte
prozess data
(flags and
slave 1/1A –
sl. 15/15A)
n+2-th
PDO
free for next
module
4 byte prozess
data
(sl. 16/16A –
sl. 23/23A)
4 byte empty
(reserved)
8 byte prozess
data
(sl. 16/16A –
sl. 31/31A)
8 byte prozess
data
(sl. 16/16A –
sl. 31/31A)
8 byte prozess
data
(sl. 16/16A –
sl. 31/31A)
8 byte
prozess data
(sl. 16/16A
– sl.
31/31A)
n+3-th
PDO
free for next
module
free for next
module
8 byte prozess
data
(slave 1B -
slave 15B)
8 byte prozess
data
(slave 1B -
slave 15B)
8 byte
prozess data
(slave 1B -
slave 15B)
n+4-th
PDO
free for next
module
8 byte prozess
data
(slave 16B -
slave 31B)
8 byte
prozess data
(slave 16B -
slave 31B)
n+5-th
PDO
free for next
module
8 byte
empty
(reserved)
n+6-th
PDO
free for next
module
Here, the n-th PDO represents the first PDO occupied by the AS-interface
Master module. It contains the status / control byte, one empty byte and up to
six bytes of mailbox data.
If the length of the permanently superimposed mailbox is 0 bytes, then the nth
PDO only contains the status / control byte and one empty byte.
If the process image of the AS-interface Master module is 12 bytes or 20 bytes
in size, the last PDO is not fully occupied. A further module then starts with
the next PDO.
Note
When the mailbox size is 6 bytes and 62 AS-interface slaves are
connected, a process image size of 40 bytes is sufficient to transmit all
process data. The module then occupies five PDOs.
The following assignment of the process image size to the number of occupied
PDOs applies in the operating mode with suppressable mailbox (Mode 2).
