Operating instructions

129
Operating the Scale
Synchronization
During data communication between
the scale and an on-line device
(computer), messages consisting
of ASCII characters are transmitted
via the interface. For error-free data
communication, the parameters for
baud rate, parity, handshake mode
and character format must be the
same for both units.
You can set these parameters in the
Setup menu so that they match those
of the on-line device. You can also
define parameters in the scale to
make data output dependent on
various conditions. The conditions
that can be configured are described
under each of the application
program descriptions.
If you do not plug a peripheral device
into the scale interface port, this will
not generate an error message.
Handshake
The scale interface (Sartorius Balance
Interface = SBI) has transmit and
receive buffers. You can define the
handshake parameter in the Setup
menu:
– Hardware handshake (CTS/DTR)
– Software handshake (XON, XOFF)
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 any connected
device to communicate.
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
(transmitting ––– byte –––> (receiving
device) ––– byte –––> device)
––– 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:
XOFF is transmitted after the 26th
character has been stored.
To prevent too many control
commands from being received at
one time, XON is not transmitted until
the buffer is almost empty.
Activating Data Output
You can define the data output
parameter so that output is activated
either when a print command is
received or automatically and
synchronously with the scale display
or at defined intervals (see
application program descriptions and
auto print setting).
Data Output by Print Command
The print command can be
transmitted by pressing p or by
a software command (Esc P).
Automatic Data Output
In the “auto print” operating mode,
data are output to the interface port
without an extra print command.
You can choose to have data output
automatically at defined print intervals
with or without the stability parameter.
Whichever parameter you select,
the data will be output as the
readouts appear on the scale display.
The display update frequency
depends on both the model of the
scale and the current operating status.
If you select the auto print setting,
data will be transmitted immediately
the moment you turn on the scale. In
the Setup menu, you can configure
whether this automatic output can be
stopped and started by pressing p.