YOKOGAWA WT1600FC User Manual page 18

2.4 Handshaking
3 XON-RS
4 CS-RS
Precautions Regarding Data Receiving Control
2-6
Transmission data control
A software handshake status is established between the instrument and host
computer. The instrument will stop a data transmission when an X-OFF signal is
received from the host computer, and will resume transmission when the next X-ON
signal is received. A CS signal from the host computer is ignored.
Reception data control
A hardware handshake status is established between the instrument and host
computer. When the instruments reception buffer vacancy reaches 64bytes, an "RS =
False" status will be established. When the reception buffer vacancy reaches 192
bytes, an "RS = True" status will be established.
Transmission data control
A software handshake status is established between the instrument and host
computer. The instrument will stop a data transmission if a "CS = False" status is
established, and will resume the transmission when a "CS = True" status is
established. The X-OFF and X-ON signals from the host computer are processed as
data.
Reception data control
A hardware handshake status is established between the instrument and host
computer. When the instruments reception buffer vacancy reaches 64bytes, an "RS =
False" status will be established. When the reception buffer vacancy reaches 192
bytes, an "RS = True" status will be established.
When handshaking is used to control the reception of data, data may still be sent from
the computer even if the free space in the receive buffer drops below 64 bytes. In this
case, after the receive buffer becomes full, the excess data will be lost, whether
handshaking is in effect or not. Data storage to the buffer will begin again when there is
free space in the buffer.
256 bytes
Used
Used
Note
It is necessary to create a host computer program which prevents the buffers of both the
instrument and the computer from becoming full.
Free, 64 bytes
Free, 192 bytes
Used
Data Receiving Control using Handshaking
When handshaking is in use,
reception of data will stop when the
free space in the buffer drops to 64
bytes since data cannot be passed to
the main program fast enough to
keep up with the transmission.
After reception of data stops, data
continues to be passed to the internal
program. Reception of data starts
again when the free space in the
buffer increases to 192 bytes.
Whether handshaking is in use or not,
if the buffer becomes full, any
additional data received is no longer
stored and is lost.
IM 760151-17E