Mitsubishi MELSEC LJ71C24, Руководство пользователя

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10 DATA COMMUNICATION USING THE NONPROCEDURAL PROTOCOL
POINT
When the reception abnormal detection (X4/XB) turns ON, read the error code from
the buffer memory below, and then check the type of error and take corrective
action based on the information found in Chapter 15.
• Data reception result (addresses: 258
H
/268
H
)
(b) Setting values that can be changed
Of the initial settings from GX Works2 stored in the buffer memory, only the
following setting values can be changed after data communication has
started.
• Received data count designation (addresses: A4
H
/144
H
)
• Receive complete code designation (addresses: A5
H
/145
H
)
(c) Timing and procedure for changing the setting values
1) Timing of change
To change the receive complete code and received data count after
data communication has started, change the setting when the status of
the I/O signals relating to the reading of receive data is as follows.
• Reception data read request (X3/XA) or reception abnormal
detection (X4/XB): ON
• Reception data read completion (X1/Y8): OFF
2) Change procedure
When data reception from an external device causes the reception
data read request (X3/XA)/reception abnormal detection (X4/XB) to
turn ON, turn ON the reception data read completion (Y1/Y8) after
performing the following.
• Read the receive data.
• Change the setting values for the receive complete code and the
received data count.
(Example) When reading data received in the CH1 side interface
External
device side
Data 1 Data 2
CPU module side
(X3)
Reception data read
completion
Received data count designation
(address: A4
H
)
Receive complete code designation
(address: A5
H
)
Setting value-A
1)
2)
3) 5)
4)
Reads
receive data
Data read request using
setting value -A/-1 Data read request using
setting value -B/-2
Reads
receive data
Setting value-1
Setting value-B
Setting value-2
(Y1)
Reception data read
request