Mitsubishi MELSEC LJ71C24, Руководство пользователя

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10 DATA COMMUNICATION USING THE NONPROCEDURAL PROTOCOL
10.1.6 Received data count and receive complete code settings
(1) Setting method before receiving data
The following default values have been set for the received data count and
receive complete code that are used for data reception with the nonprocedural
protocol.
The received data count and the receive complete code setting value can be
changed by the sequence program before data receive processing. (Refer to (3))
The default value can be changed in the following items of GX Works2.
[Various_Control_Specification] screen "For data reception" "Receive
complete code designation" or "Received data count designation"
For details, refer to Section 7.2.
Setting data
Default
value
Allowable range
Buffer memory address where
the setting value is stored
Remarks
Received data
count
511 (1FF
H
)
Less than the size of the
receive data storage area
A4
H
/144
H
Unit is in accordance with the
word/byte units designation
0000
H
to 00FF
H
When any code is set
Receive
complete code
0D0A
H
(CR+LF)
FFFF
H
A5
H
/145
H
When there is no receive
complete code
(2) Setting method after receiving data
Other than through the setting using GX Works2 or the TO instruction at the
startup of the C24, the received data count and receive complete code setting
values can be changed even after data communication has started if the timing is
as shown in the chart below.
The following describes the procedure for changing setting values for data
reception via the nonprocedural protocol after the start of data communication,
and for the resumption of data reception processing. Specifically, the module
restrictions are explained, along with the timing and procedure for changing the
setting values.
(a) How to receive data
Reception using a dedicated instruction (INPUT) or an interrupt program
( 1) cannot be performed. (Transmission using a dedicated instruction
(OUTPUT) can be performed.) Data must be received using the FROM
instruction in the main program.
The following describes the I/O signals. (A program example is shown on
the following page.)
1 For details on the data reception using interrupt programs, refer to the
User's Manual (Application).
I/O signal Device that turns ON/OFF
CH1 side CH2 side
Signal name
CPU
module
C24
Timing
X3 XA
Reception data read request
X4 XB
Reception abnormal detection
Reception
Y1 Y8
Reception data read completion
(Only when normal)
(Only when abnormal)