Owner manual

3 Installation

746 VA Trace Analyzer / 747 VA Stand

3-34

3.9.2 Tubing connection for addition of standard solutions

For the addition of standard solutions in the µL-range into the measuring vessel of

the 747 VA Stand the 4-way microtip 4747 (6.1824.000) should be used. It is fitted

with 4 lengths of PTFE tubing with connection nipples for direct attachment to the

Exchange unit of the 685 Dosimat. To ready the 685 Dosimat for automatic dis-

pensing, proceed as follows:

Mount Exchange unit on 685 Dosimat

• Procedure, see section 2 of 685 Instructions for Use.

Insert 4-way microtip in 747 VA Stand (see section 3.3.2)

• Remove stopper from nipple 4444 and insert 4-way microtip 4747 into nipple

4444 as far as it will go (see Figs 7 and 9).

• Tighten nipple 4444 using a 6.2739.000 Wrench (accessory of 6.3014.XXX

Exchange unit) so that the 4-way microtip 4747 can no longer move.

• Pull the 4 lengths of PTFE tubing of the 4-way microtip 4747 in succession

from above through the opening 8686.

Connect PTFE tubing to Exchange unit

• Unscrew the attached 6.1805.100 FEP Tubing

(L = 40 cm) from connection 2 (connection for burette

tip) of the flat stopcock on the Exchange unit mounted

on the Dosimat.

• Screw connection nipple of the PTFE tubing of the

4-way microtip 4747 onto connection 2 of the flat stop-

cock on the Exchange unit mounted on the Dosimat.

Close unused PTFE tubings

• Screw a 6.1808.000 Coupling (accessory of 747 VA Stand) on each

unused PTFE tubing of the 4-way microtip 4747.

• Screw a 6.1446.040 Dummy stopper (accessory of 747 VA Stand) on

each 6.1808.000 Coupling.

Initialize Dosimat(s)

• Switch on 746 VA Trace Analyzer using the mains switch 1111.

• Select dialog page "DOSIMATS".

• If volumes ≤ 50 µL should be dispensed, set parameter V.init to

0.05 mL.

• Set parameter V.tube in to 1.7 mL.

• Set parameter V.tube out to 0.2 mL.

• Press <Prime all> for initializing all attached Dosimats or select desired

Dosimat with the cursor keys <ç> or <è> and press <Prime Dosi-

mat>: The burette cylinder is filled and excess solution is expelled to the

measuring vessel. With standard accessories, all tubings to the measur-

ing vessel will have been filled at the end of the initializing procedure.

• Start the initializing procedure a second time by pressing the softkey

<Prime all> or <Prime Dosimat> again.

• Start the initializing procedure a third time by pressing the softkey <Prime

all> or <Prime Dosimat> again.