6 DATA COMMUNICATION USING THE NON PROCEDURE PROTOCOL MELSEC-Q

POINT

(1)Receive data can also be read using interrupt programs.

For more details on reading receive data with interrupt programs, see Chapter 4 of the User's Manual (Application).

Note that if the reading of data received from the same interface is to be performed, it is not possible to combine the reading of data received by the main program and reading of data received by the interrupt program. Accordingly, use one or the other of the above programs to read the data received.

(2)The SPBUSY instruction is used to read the execution status when using a dedicated instruction. (See Chapter 9.)

(3)More than one INPUT instruction cannot be executed simultaneously. Execute the next INPUT instruction only after the execution of the first INPUT instruction is completed.

(4)When the communication data count is set in word units, and if the received data count is an odd byte when requesting the reading of received data to the

PLC CPU, the receive data count is processed as follows:

Receive data count = Receive data byte count/2 … Fractions following the

decimal point are rounded up

Also, 00H is stored in the higher byte of the final data storage position in the receive area where receive data is stored.

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