Sartorius ME415S Operating Instructions Manual page 138

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
configured 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 –––>
––– 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 trans-
mitted 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 automatical-
ly and synchronously with the balance dis-
play or at defined intervals (see application
program descriptions and auto print set-
ting).
Data Output by Print Command
The print command can be transmitted
by pressing p/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 an
extra print command. You can choose to
have data output automatically at defined
print intervals with or without the stability
device) 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 p/r.
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