<Toc> <Ind>
<7. I/O Communications >
7-9
IM 34M6H28-01E
1st Edition : Feb.01,1999-00
■
High order/ low order byte swapping of multiple byte data
The encoding rules are different for data on the FA-M3 and DeviceNet. Hence in multiple-
byte data it is necessary to swap the high order/low order bytes every 2 bytes.
Examples are shown in Figures 7.6 and 7.7. For programming, see Section 7.6, “I/O Data
Access (Example of Programming).”
$00
$00
$01
DeviceNet
$78
$56
$34
$12
"A"
"B"
Other node
$01
$78
$56
$34
$12
"A"
500
Data location number
This module
501
502
503
"B"
$01
$00
$56
$78
$12
$34
"A"
D0100
Data register number
When reading data from this module, it is
necessary to swap the high order/low order
bytes using a ladder or BASIC program
Input data
. 16 bit integer (bit string): $0100
. 32 bit integer (bit string): $12345678
. 1 byte character
: "A"
. 1 byte character
: "B"
CPU module
D0101
D0102
D0103
"B"
F0706.EPS
Figure 7.6 Example of Swapping of Input Data
$00
$00
$01
DeviceNet
$78
$56
$34
$12
"A"
"B"
Other node
$01
$78
$56
$34
$12
"A"
1000
I/O data location number
This module
1001
1002
1003
"B"
$01
$00
$56
$78
$12
$34
"A"
D0100
Data register number
When writing data into this module, it is
necessary to swap the high order/low
order bytes using a Ladder or BASIC program.
Output data
. 16 bit integer (bit string): $0100
. 32 bit integer (bit string): $12345678
.1 byte character string
: "A"
.1 byte character string
: "B"
CPU module
D0101
D0102
D0103
"B"
F0707.EPS
Figure 7.7 Example of Swapping of Output Data
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