Mitsubishi Electric QJ71C24N-R4 - Data Reception from the External Device; Receiving Methods

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MELSEC-Q
6 DATA COMMUNICATION USING THE NON PROCEDURE PROTOCOL
6.1 Data Reception from the External Device
This section explains data reception from the external device.
6.1.1 Receiving methods
The following shows the methods for receiving data in any format using the non-
procedure protocol.
There are three methods for receiving data: the "reception by the receive complete
code" for receiving variable length messages, and the "reception by the receive data
count" for receiving fixed length messages, and the "reception by a timeout of the no-
reception monitoring time (timer 0)" for the case when the receive complete code and
receive data count have not been determined.
The receive complete code and received data count used for data reception can be
changed to any setting values by the user using GX Configurator-SC.
Method Application
Reception by the receive complete code Receives variable length messages.
Reception by the receive data count Receives fixed length messages.
Reception by a timeout of the no-reception
monitoring time (timer 0)
Receives a message of which the receive complete code and receive data
count have not been determined. For a specification of the non-reception
monitoring time (timer 0), refer to the User's Manual (Application).
Programmable
controller
CPU
1)
Reception data
read request
Receiving area
(buffer memory)
Receive data
Receive data
count
10
STX
D
F
H
(02
H
)
(48
H
)
(46
H
)
(44
H
)
B
(42
H
)
(0A
H
)
A
(41
H
)
G
(47
H
)
E
(45
H
)
C
(43
H)
ETX
(03
H
)
(00
H
)
Q series C24
STX
A
BCDEFGHETX
Head data Receive complete code
(02
H
)(41
H
)(48
H
)(47
H
)(46
H
)(45
H
)(44
H
)(43
H
)(42
H
)(03
H
)
Transmission data
External device
RUN.
ERR.
USER.
BAT.
BOOT.
RS-232
USB
Q25HCPU
MODE.
2) 3)
INPUT
instruction
1) When data is received from the external device using either "reception via receive
complete code" or "reception via received data count" method, the reception data
read request (X3/XA) turns ON.
2) Control data is stored in the device designated with the INPUT instruction.
3) When the INPUT instruction is executed, receive data is read from the reception
data storage area of the buffer memory.
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