11-5
IM CW120-E
Communication Functions
11
Precautions for Reception Control
While a CW120 or CW121 is controlling a data reception by a handshake,
data may be sent from the computer even when the free space in the
reception buffer is less than 256 bytes. In this case, regardless of whether a
handshake for data reception is set, overflowed data will be discarded after
the reception buffer becomes full. After free space appears in the reception
buffer, data begins being stored to the buffer again.
1024 bytes
Used
256 bytes unused
When performing a handshake, if the
free space in the buffer has decreased to
256 bytes because the internal data
transfer is too slow, the reception stops.
Used
768 bytes unused
After the status above, when data was
transfer internally and the free space in
the buffer has increased to 768 bytes, the
reception restarts.
Used
After the buffer has become full,
regardless of whether a handshake for
data receptions is set, overflowed data
will not be stored and will be discarded.
TIP
When developing the computer’s communication program, be careful about the data transmission rate
so that the reception buffer either in the CW120/121 or in the computer will not become full.
11.1 RS-232
