Yokogawa Button Operated MV2000 - Manual (Page 61)

3-3 M-4662
Using
the
Serial
Interface
1
2
3
4
5
6
7
App
Index
• Connection example
SD
RD
RS
CS
SG
SD
RD
RS
SG
• OFF-OFF/XON-XON
PC MV
SD
RD
RS
CS
SG
SD
RD
RS
SG
• XON-RS (XON-RTS)
PC MV
SD
RD
RS
CS
SG
SD
RD
RS
SG
• CS-RS (CTS-RTS)
PC MV
CS
CS
CS
2
3
8
7
5
2
3
8
7
5
2
3
8
7
5
You do not need to wire RS on the PC to
CS on the MV. However, we recommend it
so that the cable can be used in either
direction.
Handshaking
When using the RS-232 interface for transferring data, it is necessary for equipment on
both sides to agree on a set of rules to ensure the proper transfer of data. The set of
rules is called handshaking. Because there are various handshaking methods that can
be used between the MV and the PC, you must make sure to choose the same method
for both the MV and the PC.
You can choose any of the four methods in the table below for the MV.
Data transmission control
(Control used to send data to a computer)
Data Reception Control
(Control used to receive data from a computer)
Software
handshaking
Software
handshaking
Handshaking Combinations (Yes indicates that it is supported)
OFF-OFF
XON-XON
XON-RS
CS-RS
Handshaking
Stops sending
when X-OFF is
received. Resumes
when X-ON is
received.
Stops sending
when CS (CTS)
is false.
Resumes
when it is true.
No
handshaking
No
handshaking
Sends X-OFF
when the receive
data buffer is 3/4
full. Sends X-ON
when the receive
data buffer is
1/4 full.
Sets RS (RTS) to
false when the
receive data buffer
is 3/4 full. Sets RS
(RTS) to true when
the receive data buffer
is 1/4 full.
Hardware
handshaking
Hardware
handshaking
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
• OFF-OFF
• Data transmission control
There is no handshaking between the MV and the PC. The MV treats the “X-OFF”
and “X-ON” signals that are received from the PC as data and ignores the CS
signal.
• Data reception control
There is no handshaking between the MV and the PC. When the received buffer
becomes full, the MV discards all of the data that overflows.
RS = True (fixed).
3.2 Connecting the MV