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 communi-
cation, 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)
– Software handshake (XON, XOFF)
Hardware Handshake
With a 4-wire interface, 1 more charac-
ter 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
(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 in 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 has
transmitted all but 14 characters.
If the device addressed does not under-
stand the control command, the SBI
receiving device activates DTR (Data
Terminal Ready) after 6 more characters
have been received. The busy signal is
deactivated by XON (14 characters).
Activating Data Output
You can define the data output param-
eter 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 program descriptions
and auto print settings).
Data Output by Print Command
The print command can be transmitted
by pressing
p
or by a software com-
mand (Esc P).
Automatic Data Output
In the “auto print” operating mode,
data are output to the interface port
without a print command. You can
choose to have data output auto-
matically 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 state.
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
p
.
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