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Process Image
WAGO-I/O-SYSTEM 750
750-657 IO-Link Master
Manual
Version 1.0.2, valid from FW/HW-Version 02/01
6.4.1
Unfragmented Process Data
If the size of a port segment is equal to or larger than the process data width of the
attached IO-Link device and fragmentation for this segment is switched off, the
process data of the IO-Link device is transferred via internal bus. The following
example shows the process data for an attached IO-Link device with a Mailbox
size of 2 bytes, process data width of 3 bytes (segment width: 5 bytes) on port 3.
Table 16: Distribution of the process data in the IO-Link master, example
Byte 0 1 2 3 4 5 6
7 8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Content
C
ont
ro
l byt
e
/ St
at
us byt
e
M
ailbo
x / Reg
ister comm..
M
ailbo
x / Reg
ister comm.
SIO byte
Segme
nt
P
ort
1
Segme
nt
P
ort
1
Segme
nt
P
ort
1
Segme
nt
P
ort
2
Segme
nt
P
ort
2
S
eg
m
en
t P
ort
3
=
0x
12
S
eg
m
en
t P
ort
3
=
0x
34
S
eg
m
en
t P
ort
3
=
0x
56
Segme
nt
P
ort
3 =
0x
00
Segme
nt
P
ort
3 =
0x
00
Segme
nt
P
ort
4
Segme
nt
P
ort
4
Segme
nt
P
ort
4
Segme
nt
P
ort
4
Segme
nt
P
ort
4
Segme
nt
P
ort
4
Segme
nt
P
ort
4
Un
use
d, 0
x00
Un
use
d, 0
x00
Un
use
d, 0
x00
Port
1
2
3
4
Segment size > process data width of the IO-Link device!
If the segment size is equal to or greater than the process data width of the IO-
Link device, the excess bytes of the input data are populated with "0x00". The
excess bytes are ignored in the output direction.
Segment size < process data width of the IO-Link device!
If the segment size is smaller than the process data width of the IO-Link device
and fragmentation is set to "inactive", the input process data is cut upwards. In the
output direction, the missing bytes are populated with zeros.
Notice
: Avoid this configuration because the PLC output data does not
correspond to the output value!
6.4.2
Fragmented Process Data
An IO-Link device can process up to 32 bytes of process data per port and per
direction. With 4 ports, up to 128-byte process data and 128-byte process output
data is possible.
Because the data width of the internal bus may not be sufficient, the IO-Link
master provides the option of fragmented transfer of process data. When
fragmentation is switched on, the data is transferred fragmented per port
independent of each other and in the respective port segment.
More information about fragmentation is available in the appendix, section
"Mailbox 2.0 Transmission Mechanism".