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APPENDIX
Appendix 7.5 How to Clear Reception Data Stored in the Receive Buffer
Appendix 7.6 Sending or Receiving Character Data of 256 Bytes or More
(Example of transmission)
Data that must be sent
(Example of reception)
Data entered at one time,
among the data received
Data entered at one time,
among the data received
Data entered at one time,
among the data received
App - 42
If 1 or greater is specified in the receive buffer specification when the communication
channel is opened, the data received from the external device is stored in the receive
buffer of the specified size.
Use one of the methods indicated below to clear the reception data stored in the
receive buffer and then store data received later in the receive buffer anew.
1) Close the currently open target communication channel, then reopen it.
2) Specify the number of requested characters for the size of the receive buffer and
the timeout value as 1 using the ZRECEIVE instruction, then request to receive
data.
All of the data returned by this reception request will be ignored.
3) Change the setting value using the ZCNTL instruction.
When sending or receiving character data of 256 bytes or more to/from an external
device in non procedure mode via the RS-422 interface or RS-232C interface, divide
the data into units of a maximum 255 bytes.
This must be done because a BASIC program cannot handle character data of 256
bytes or more per transmission or reception request.
Data transmitted
The user divides
the data into units
Data transmitted
of maximum 255
bytes per unit.
Data transmitted
Each is stored in the character
variable or character array variable.
(This will become the output element.)
ZRECEIVE # to
ZRECEIVE # to
ZRECEIVE # to
at one time
ZSEND # to
at one time
ZSEND # to
at one time
ZSEND # to
Receive buffer
The user divides
and enters the data.
MELSEC-Q
Transmission
Transmission
Transmission
Reception
App - 42
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