YOKOGAWA wt1600, User Manual

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2-6
IM 760101-11E
2.4 Handshaking
3 XON-RS
• 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 intstruments 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.
4 CS-RS
• 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 shen 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 intstruments 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.
Precautions Regarding Data Receiving Control
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 Free, 64 bytes
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.
Used
Free, 192 bytes
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.
Used
Whether handshaking is in use or not,
if the buffer becomes full, any
additional data received is no longer
stored and is lost.
Data Receiving Control using Handshaking
Note
It is necessary to create a host computer program which prevents the buffers of both the
intrument and the computer from becoming full.