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MELSEC-Q
6 DATA COMMUNICATION USING THE NON PROCEDURE PROTOCOL
(2) Setting values that can be changed
Of the initial settings from GX Configurator-SC stored in the buffer memory, only
the following setting values can be changed after data communication has
started.
• Received data count (buffer memory addresses: A4
H
, 144
H
)
• Receive complete code (buffer memory addresses: A5
H
, 145
H
)
(3) 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 signal (X3, XA) or reception abnormal
detection signal (X4, XB): ON
• Reception data read completion signal (X1, Y8): OFF
2) Change procedure
When data reception from an external device causes the reception data read
request signal/reception abnormal detection signal to turn ON, turn ON the
reception data read completion signal 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
PLC CPU side
Read request signal
(X3)
Read completion signal
(Y1)
Received data count setting area
(buffer memory address: A4
H
)
Receive complete code setting area
(buffer memory 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
(Program example: I/O signals for the Q series C24 are from X/Y00 to X/Y1F)
Reads the data that is equal to the receive
data count.
Change the setting value for the received
data count as needed.
Change the setting value for the receive
complete code as needed.
Reads receive data count.
Turns ON the read complete signal.
( 1)
1 When unit is in bytes
Read request
1)
2)
2)
3)
4)
5)