Rice Lake Sartorius Midrics 1 and 2 Series - Installation Instructions - Manual (Page 16)

16
Synchronization
Data communication between the dis-
play and control unit and a computer
takes the form of messages
(“telegrams") made up of ASCII code.
For error-free data communication, the
settings for baud rate, parity, hand-
shake 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 peripheral
device to the display and control unit's
interface port, this will not generate an
error message.
Handshake
The weighing instrument interface (Sar-
torius 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).
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 pre-
vents 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.