Metrohm 711 Liquino - Manual (Page 140)

5.1 The advantages of the 711 Liquino
711 Liquino, Instructions for use 134
process until the temperature is again within the limits, interruption
of the dosing process until it is continued manually (HOLD) or ter-
minating the dosing process. A signal to an external instrument can
also be sent by activating alarm pins at the remote interface. With
the help of a relay box, e.g. Metrohm Relay Box 731, it is possible to
switch various auxiliary instruments, e.g. cooling baths, heating
baths, etc.
♦ Handling small and even very small amounts of reagent is possible
without any problems. Different dosing units with cylinder volumes
from 2 mL to 50 mL are available. Continuous and controlled rea-
gent addition is guaranteed by all dosing units.
Safety aspects
By replacing dropping funnels by a single 711 Liquino, to which up to four
dosing drives can be connected, it is possible to automate an experiment
and in this way to work in a closed system. This means:
♦ No protective measures need to be taken against aggressive va-
pors. This also applies to the preparation of the reagents. Previous
weighing out or measuring in the amounts of reagents required is
no longer necessary. Thanks to a range of different bottle adapt-
ers/screw threads it is possible to take reagents directly from
standard reagent bottles and original chemical storage containers.
♦ Direct contact with chemicals is no longer required. The 'PREP' and
'EMPTY' Liquino functions ensure that the dosing units are filled and
emptied automatically.
♦ External influences such as atmospheric humidity can be ruled out
in a closed system. This considerably increases the reproducibility
of the experiments.
♦ While the dosing drives with the reagents can stand directly beside
the experimental apparatus, the 711 Liquino and therefore the elec-
tronics can be positioned outside the fume cupboard. This allows
the experimental setup to be operated with the fume cupboard win-
dow closed; it also increases the working life of the 711 Liquino in
rough surroundings.
Programmable runs
Handling procedures can be programmed step-by-step as run sequences.
An experiment can be completely automated. This means that potential
dangers can be reduced and also increases the reproducibility.
♦ Individual dosing steps can be stored as separate methods and
programmed in a run sequence as required.
♦ Time-related commands can be inserted in the run in addition to the
dosing steps, see page 91. The inclusion of waiting periods (when
waiting for reaction times to elapse), start delays or starting runs
(also single part steps) according to time can be made without any
problems. This allows the time required for a reaction to be carried
out to be calculated exactly.
♦ Additional communication commands (see page 85ff) can control
other instruments. Bidirectional communication with other instru-
ments is possible via the serial RS232 interface or parallel remote
leads (25-pin SubD connection, TTL-level).