Mitsubishi L02CPU User Manual page 114

(a) TCP standard receive mode
When data are received, they are stored in the Socket communication receive data area, and SD1286 turns on.
If data are received exceeding the specified receive data size, the excess data are read out the next time.
The receive data size is set to 300 bytes, and 500-byte data are received.
Ex.
Reading receive data
Socket communication
receive data area
SD1286
(b) TCP fixed-length receive mode
When data are received, they are stored in the Socket communication receive data area, and SD1286
(Receive state signal) turns on.
However, if the size of the data does not reach the specified receive data size, SD1286 does not turn on.
Data reception is repeated and once the data size reaches to the specified size, SD1286 turns on.
If data are received exceeding the specified receive data size, the excess data are read out the next time.
The receive data size is set to 300 bytes, and 200-byte data are consecutively received.
Ex.
Reading receive data
Socket communication
receive data area
SD1286
● Effective use of devices
Devices can be effectively used by setting the receive data size to less than 1024 words while the default size of the
receive data storing devices for the SP.SOCRCV and S.SOCRCVS instructions is 1024 words.
● Prevention of receive data fragmentation
Data from the connected device may be fragmented depending on the line type. To prevent this, the receive data size can
be specified in the TCP fixed-length receive mode.
● Prevention of receive data binding
Separately sent data may be combined depending on the interfacing device due to a delay in receive processing of the
program. To prevent this, the receive data size can be specified in the TCP fixed-length receive mode.
112
Data stored
(300 bytes)
ON
OFF
Data reception
(500 bytes)
Data cannot be read out because
the receive data size is not reached.
Data stored
(200 bytes)
ON
OFF
Data reception
(200 bytes)
SP.SOCRCV or
S.SOCRCVS
instruction
Data stored
Data reading
(200 bytes)
SP.SOCRCV or
S.SOCRCVS
instruction
Data reading
Data stored
(300 bytes)
Data reception
(200 bytes)
SP.SOCRCV or
S.SOCRCVS
instruction
Data reading
The remaining 100
bytes will be stored
at the next data
reception (200 bytes).