Mitsubishi Electric AJ71QC24 Manual page 42

4. COMMUNICATIONS USING A DEDICATED PROTOCOL MELSEC QnA
Subcommand
Subcommand designates the read/write units, kind of device designated, and the data
read conditions.
In this guidebook, the read and write operations are performed in word units or bit units.
Therefore, the subcommand is set as shown below.
b7 b6 b5 b4 b3 b2
b l bO
0:
Word units
1 : Bit
unlts
1 9 h
Error No.
The error No. shows the error contents when the opposite device sent a NAK response.
If two or more errors are generated at the same time, the error No. detected first is sent.
For instance, the following shows an example
of
connection of three networks
I
Erternal
I
1
device
I
1 M p l 1
Ns2 2Mpl
2Ns2
$
QLP21
T
AJ71 AJ71
QnACPU
$
QC24 AJ71 QnACPU
Q
2
G
QLP21
anAcPu
A J ~ I
w
o_
!SI
G
o_
QLP21 QLP21
[ I )
C
73
73
Y
o_
r
!S)
( S I
07
!S)
73
r
-
Network No.
1
Network No.
2
1
device
I
1 M p l 1
Ns2 2Mpl
$
QLP21
T
AJ71 AJ71
QnACPU
$
QC24 AJ71 QnACPU
w
o_
!SI
G
o_
QLP21 QLP21
[ I )
C
73
[
!S)
!S)
73
-
73
r
Y
o_
Network No.
1
Network No.
2
js
QLP21
I I
f
QnACPU AJ71
C
73
Y Y
3Ns2 3Ns3
3Ns4
The following shows the settings when an external device uses QnA frame format 1 to access the
QnACPU indicated by
Character
4 - 9