Mitsubishi Electric AJ71C24-S6 User Manual page 129

8. COMMUNiCATlONS USING DEDICATED PROTOCOLS
MELSEC-A
8.4.5
Setting protocol data
(1) Control code
D
All control codes are sent and received in hexadecimal. They are
shown in the following table.
I
STX
j
02H
I
Start of Text
/
CL
/
OCH
I
Clear
Signal
NUL
p - ~ ~
EIX 03H End of Text
End of
Transmission
Code
(Hexadecimal)
OOH
Carriage Return
Negative
Acknowledge
I
ENQ
1
05H
I
Enquiry
/
G
1
47H
I
Good
Description
Null
(a) The NUL code (OOH) is ignored in all messages. If a NUL code is
included in a message,
it
is processed as if it did not exist.
Signal
LF
ACK
(b) In format
3,
control code "GG" is equivalent to ACK and "NN" is
equivalent to NAK.
(c) After receiving an EOT or CL code, the AJ71C24 initializes transmis-
sion but does not answer. The initializing code depends on the
format as indicated below. At this time there is no answer from the
Code
(Hexadecimal)
OAH
06H
Format 1 to 3
Description
Line Feed
Computer
Acknowledge
(2) Block number
Format 4
N
Or
Computer
The block number is an optional number assigned as a data reference
number for the computer. Block numbers are used to arrange data, etc.
Block numbers may be from OOH to FFH in 2-digit ASCII (hexadecimal).
4EH No Good