WAGO -I/O-SYSTEM 750 Series Manual page 51

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).
Process
image size
n-th
PDO
n+1-th
PDO
n+2-th
PDO
n+3-th
PDO
n+4-th
PDO
n+5-th
PDO
n+6-th
PDO
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 n-
th 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.
WAGO-I/O-SYSTEM 750
I/O Modules
12 bytes 20 bytes
1 status-/ 1 status-/
control byte control byte
1 empty byte 1 empty byte
6 byte 6 byte
mailbox mailbox
4 byte process
data 8 byte process
(flags and data
Slave 1/1A - (flags and
Slave 7/7A) Slave 1/1A –
4 bytes empty Sl. 15/15A)
(reserved)
4 byte process
data
free for next (Sl. 16/16A –
module Sl. 23/23A)
4 bytes empty
(reserved)
free for next
module
Fieldbus-specific behavior
24 bytes 32 bytes
1 status-/ 1 status-/
control byte control byte
1 empty byte 1 empty byte
6 byte 6 byte
mailbox mailbox
8 byte process 8 byte process
data data
(flags and (flags and
Slave 1/1A – Slave 1/1A –
Sl. 15/15A) Sl. 15/15A)
8 byte process 8 byte process
data data
(Sl. 16/16A – (Sl. 16/16A –
Sl. 31/31A) Sl. 31/31A)
8 byte process
free for next data
module (Slave 1B –
Slave 15B)
free for next
module
• 51
CANopen
40 bytes 48 bytes
1 status-/ 1 status-/
control byte control byte
1 empty byte 1 empty byte
6 byte 6 byte
mailbox mailbox
8 byte process 8 byte process
data data
(flags and (flags and
Slave 1/1A – Slave 1/1A –
Sl. 15/15A) Sl. 15/15A)
8 byte process 8 byte process
data data
(Sl. 16/16A – (Sl. 16/16A –
Sl. 31/31A) Sl. 31/31A)
8 byte process 8 byte process
data data
(Slave 1B – (Slave 1B –
Slave 15B) Slave 15B)
8 byte process 8 byte process
data data
(Slave 16B – (Slave 16B –
Slave 31B) Slave 31B)
free for next 8 bytes empty
module (reserved)
free for next
module