6 DATA COMMUNICATION USING THE NON PROCEDURE PROTOCOL MELSEC-Q

(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: A4H, 144H)

•Receive complete code (buffer memory addresses: A5H, 145H)

(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

Data 1

 

 

Data 2

 

 

 

 

 

 

 

device side

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PLC CPU side

 

 

Data read request using

 

 

Data read request using

 

 

setting value -A/-1

 

 

setting value -B/-2

 

 

 

 

 

 

 

Read request signal

 

1)

 

 

 

 

 

 

 

 

 

 

 

(X3)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2)

 

 

 

 

Reads

 

 

 

 

 

 

receive data

 

 

 

 

 

Reads

 

 

Read completion signal

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

receive data 3) 5)

 

 

 

 

 

 

 

 

(Y1)

 

 

4)

 

 

 

 

 

 

 

 

 

Received data count setting area (buffer memory address: A4H) Receive complete code setting area (buffer memory address: A5H)

Setting value-A

Setting value-1

Setting value-B

Setting value-2

Read request 1)

(Program example: I/O signals for the Q series C24 are from X/Y00 to X/Y1F)

2)

 

Reads receive data count.

 

 

 

 

( 1)

 

2)

 

Reads the data that is equal to the receive

 

 

3)

 

data count.

 

Change the setting value for the received

 

 

4)

 

data count as needed.

 

Change the setting value for the receive

 

 

 

5)

complete code as needed.

 

Turns ON the read complete signal.

 

 

 

 

 

1 When unit is in bytes

 

 

 

 

 

 

 

 

 

 

6 - 21

6 - 21