Synchronization - Sartorius CH1NE Operating Instructions Manual

Synchronization

Data communication between the
indicator and a computer takes the form
of messages ("telegrams") made up of
ASCII code. For error-free data commu-
nication, the settings 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.
If you do not connect a peripheral
device to the indicator's interface port,
this will not generate an error message.
Handshake
The weighing instrument interface
(Sartorius Balance Interface = SBI) has
transmit and receive buffers. You
can define the handshake parameter in
the indicator'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
switched on, XON must be transmitted
to enable a connected device to com-
municate.
When the software handshake is
configured in the Setup menu, the
hardware handshake becomes active
after the software handshake.
The data transmission sequence
is as follows:
Scale ––– byte –––> Computer
(trans- ––– byte –––> (receiving
mitting ––– byte –––> device)
device) ––– 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.
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