Minebea Intec YDO01M-232 Notice D'installation page 16

Configuring the Interface
Synchronization
Data communication between the
display and control unit and a com-
puter takes the form of messages ("tel-
egrams") made up of ASCII code. For
error-free data communication, the set-
tings for baud rate, parity, handshake
mode and character format must be the
same at both ends.
You can configure the interface settings
in the Setup menu so that they match
those of the computer. You can also
define parameters in the indicator to
make data output dependent on various
conditions. The conditions that can be
configured are listed in the descriptions
of the application programs (see oper-
ating instructions for the Midrics scale).
If you do not connect a periph-
eral device to the display and control
unit's interface port, this will not gener-
ate an error message.
Handshake
The weighing instrument interface
(Minebea Intec Balance Interface = SBI)
has transmit and receive buffers. You
can define the handshake parameter
in the display and control unit's Setup
menu:
– Hardware handshake (CTS/DTR)
– Software handshake (XON, XOFF)
Hardware Handshake
Hardware handshake with a 4-wire
interface: 1 more character can be
transmitted after CTS (clear-to-send).
YDO01M
16
Software Handshake
The software handshake is controlled
via XON and XOFF. When a device is
switched on, XON must be transmitted
to enable a connected device to com-
municate.
The data transmission sequence is as
follows:
Scale ––– byte –––> Computer
(trans- ––– byte –––> (receiving
mitting device)
device)
––– byte –––>
––– byte –––>
<–– XOFF –––
––– byte –––>
––– byte –––>
...
(Pause)
...
<–– XON –––
––– byte –––>
––– byte –––>
––– byte –––>
––– byte –––>
Transmitting Device
Once XOFF has been received,
it prevents further transmission of
characters. When XON is received, it re-
enables the transmitting device to send
data.
Receiving Device
To prevent too many control commands
from being received at one time, XON
is not transmitted until the buffer is
almost empty.