6DATA COMMUNICATION USING THE NON PROCEDURE PROTOCOL MELSEC-Q

(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 Q series C24 at the complete of the message to be sent from the external device.

(b)When the Q series C24 receives the receive complete code data preset in GX Configurator-SC by the user, it sends a receive data read request to the sequence program.

The read request from the Q series 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 00H to FFH range can be designated.

(d)The Q series C24 issues a receive data read request to the PLC CPU as follows, according to the set value of the receive end code.

1)When receive complete code not changed (Default value: 0D0AH) (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 Q series C24 stores the receive data up to CR+LF to the buffer memory receive data storage area and turns on the read request signal to the PLC CPU.

 

 

 

Timer 0

 

 

 

 

C

L

 

 

 

set time

 

External device

 

R

 

F

 

 

 

 

 

 

 

 

 

 

 

 

Q series C24

 

 

 

 

 

Reception data read reqest signal

(X3/XA)

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