Mitsubishi MELSEC LJ71C24, User Manual

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10 DATA COMMUNICATION USING THE NONPROCEDURAL PROTOCOL
(1) Data reception by receive complete code (for variable length
reception)
(a) This method is used to send data by adding the receive complete code set in
the C24 at the completion of setting the message from the external device.
(b) When the C24 receives the receive complete code data preset in GX Works2
by the user, it sends a receive data read request to the sequence program.
The read request from the C24 allows the sequence program to read the
receive data up to the receive complete code received from the external
device.
(c) The receive complete code can be changed to match the specifications of the
external device. An arbitrary 1-character (1-byte) code within the 00
H
to FF
H
range can be designated.
(d) The C24 issues a receive data read request to the CPU module as follows,
according to the set value of the receive end code.
1) When receive complete code not changed (Default value: 0D0A
H
)
(CR+LF is added to the end of the message and sent from the external
device.)
• If LF is received within the time set in the no-reception monitoring time
(timer 0) after CR is received, the C24 stores the receive data up to
CR+LF to the buffer memory receive data storage area and turns on
the reception data read request (X3/XA) to the CPU module.
External device
Reception data read request (X3/XA)
Timer 0
set time
C
R L
F
C24 side