Mitsubishi Electric AJ71C24-S6 User Manual page 95

6.
DATA COMMUNICATIONS USING AN M : N MULTIDROP LINK
MELSEC-A
6.2.3 Command and message format for data communications among computers
A command and message format for data communications among com-
puters with the dedicated protocol must be set.
Use any command except the commands used with the dedicated protocol
of an AJ71C24. See Section 3.3.1.
The message format basically follows the control procedure set by the mode
setting switch of each AJ71C24. See Section 8.4.
Set the data arrangement after the PC number in the message as desired.
(1)
Protocol 1 when doing data communications
Computer 1
set the
dataarrangement
BE
desired.
(WH tp sFH]
Computer 2
(2) Example of a message format (when station numbers 80H and 81H
perform data communications)
(1) If the mode setting switch of an AJ71C24 is set for the dedicated protocol mode (1 to 4) and
if the station number written in a message to be transmitted from computer 1 is OOH to 31H
(designating AJ71 C24), then the designated station (AJ71 C24) determines that message to
be a faulty message and it transmits back a message beginning with NAK to computer 1.
Always use station numbers 80H to 9FH for communications between the computers.
(2) Section 8.3 tells how to read the message format figures,
Computer 1
(Station
number SOH)
Computer 2
(Station
number 81 H)
$0
station
number
@OH)
3 8 ~ 1 3 0 ~
A
C
K
cw
Sum
=heck
I
code
(87Hl
4 M I 3 7 H
E
N
o
CW
~ r b m
Station
number
(81H)
3 8 ~ 1 3 1 ~
*ti%"
number
(BlHl
38H131H
~ r b m
station
number
(BoH)
38H12Ui
I
Command
(22)
W [ W
M=seQe
wait time
(21
32H