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Synchronization
During data communication between the
balance 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 balance 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 balance interface port, this will not
generate an error message.
Handshake
The balance 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 config-
ured in the Setup menu, the hardware
handshake becomes active after the
software handshake.
The data transmission sequence is as
follows:
Balance ––– 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 charac-
ter 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 synchronous with the balance display
or at defined intervals (see application pro-
gram descriptions and auto-print setting).
Data Output by Print Command
The print command can be transmitted by
pressing r or by a software command
(Esc P).
Automatic Data Output
In the “auto print” operating mode, data
is output to the interface port without
a 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 balance display. The display
update frequency depends on both the
model of the balance and the current
operating status.
If you select the auto print setting,
data will be transmitted immediately the
moment you turn on the balance. In the
Setup menu you can configure whether
this automatic output can be stopped and
started by pressing r.
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