Metrohm 748DH User Manual
CH-9101 Herisau/Switzerland
Phone +41 71 353 85 85
Fax +41 71 353 89 01
EMail sales@metrohm.ch
Internet http://www.metrohm.ch
748 DH Sample Changer
Instructions for Use
8.748.1003
99.01 mst, ti
Contents
Contents
1 Introduction..............................................................................................................2
1.1 Overview....................................................................................................................... 2
1.2 Sample arm positions .................................................................................................. 4
1.2.1 Positions in the XY-direction ................................................................................. 4
1.2.2 Positions in the Z-direction.................................................................................... 4
2 Sample changer start-up.........................................................................................5
2.1 Mains voltage, mains connection................................................................................ 5
2.2 Sample Changer setup................................................................................................ 6
2.2.1 Setting up the basic instrument ............................................................................ 6
2.2.2 Installation of rinsing accessories......................................................................... 7
2.3 Equipping the titration head......................................................................................... 8
2.4 Sample racks................................................................................................................ 9
2.5 Sample Changer start up............................................................................................. 9
2.6 Adjusting Sample Changer.......................................................................................... 9
3 Operation via RS232 Interface ..............................................................................11
3.1 General rules .............................................................................................................. 11
3.1.1 Tree of commands .............................................................................................. 11
3.1.2 Triggers................................................................................................................ 11
3.2 Remote control commands ....................................................................................... 12
3.2.1 Overview .............................................................................................................. 12
3.2.2 Description of the remote control commands.................................................... 13
3.3 Properties of the RS 232 Interface............................................................................. 16
4 Troubleshooting, remedying faults ......................................................................17
4.1 Troubleshooting ......................................................................................................... 17
4.2 TiNet error messages................................................................................................. 18
4.3 Readjust Sample Changer......................................................................................... 19
5 Appendix.................................................................................................................20
5.1 Technical specifications............................................................................................. 20
5.2 Sample Changer methods......................................................................................... 21
5.3 Pin assignment of I/O sockets "Auxiliary" .................................................................. 22
5.4 Warranty and certificates............................................................................................ 23
5.4.1 Warranty............................................................................................................... 23
5.4.2 Certificate of Conformity and System Validation................................................ 24
5.5 Scope of delivery, accessories .................................................................................. 26
Index ..........................................................................................................................29
748 DH Sample Changer
1 Introduction
1.1 Overview
Instrument front panel:
1
2
3
1.1 Overview
4
5
6
Instrument rear panel:
8
9
10
7
748 DH Sample Changer
11 13 14
12
15
16
1
1.1 Overview
Instrument front panel:
1 6.2053.010 cable/tubing clamps
2 Control cable
assembly see page 6.
3 Cable/tubing holder
4 Sample arm
5 Splash protection
6 Sample rack
for 48 x 250 mL beakers
or
for 136 x 75 mL beakers
7 Connection for waste tubing
2
748 DH Sample Changer
Instrument rear panel:
8 Holder for control cable
9 Sockets for control cable
10 Mains switch
11 Connection for mains cable
Mains voltage adjustment: see page 5.
In networks where the mains voltage is subject to strong HFinterference the Sample Changer should be operated with an additional
mains filter, e.g. Metrohm 615 mains filter.
12 Remote sockets for I/O lines
The beaker detector is plugged into remote socket 1.
Remote sockets 2 and 3 can be used for connecting external instruments. The lines can be activated from TiNet (see TiNet Instructions for
Use).
1.1 Overview
13 RS232 interface
for connecting a computer
14 Stirrer connection and setting the stirrer speed
Rod stirrer 722
Supply voltage: 10 VDC (I ≤ 200 mA)
15 Voltage adjustment for pump
see page 5
16 Connection for rinsing tubing
with 6.1808.050 tubing nozzle
748 DH Sample Changer
3
1.2 Overview
Y-
1.2 Sample arm positions
The sample arm is moved in both the XY-direction (rack positions) as
well as in the Z-direction.
1.2.1 Positions in the XY-direction
Left-hand rack Right-hand rack
1 Wash Soak Home
X-direction
direction
The sample arm is moved so that it only moves above samples which
have already been titrated (i.e. positions which have already been visited).
1.2.2 Positions in the Z-direction
The positions in the Z-direction are set in the TiNet configuration. They
are given in mm: measurements are made from the tower; the zero
point is 15 mm below the upper edge.
The positions in the Z-direction depend on both the type of rack used
and on the sample head fittings.
Working position
Position during titration/measurement.
The beaker detector should stand on the beaker rim.
Take care that electrodes, stirrer and buret tips are sufficiently immersed.
Rotation position, movement position
Position during the movement of the sample arm in the XY-direction.
Take care that electrodes, stirrer and buret tips are raised higher than
the beaker rims.
Rinsing position
Position during rinsing in the wash beaker.
Take care that electrodes, stirrer and buret tips are well located in the
rinsing spray of the wash beaker.
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748 DH Sample Changer
2.1 Mains voltage, mains connection
2 Sample changer start-up
2.1 Mains voltage, mains connection
Check that the voltage set on the instrument corresponds
to your mains voltage. If this is not the case then the mains
voltage must be altered:
1. Remove the mains cable.
2. Carefully open the compartment above the mains cable
with a screwdriver.
3. Remove the voltage selection drum.
4. If necessary change the fuse: remove the parts marked
with "⇒" and insert the fuses for the corresponding voltage which are given on the rear panel of the instrument.
5. Rotate the voltage selection drum so that the correct
voltage appears at the front (when the compartment is
closed this voltage will appear in the window).
6. Close the compartment again.
Set mains voltage for pump
1. Screw off the cover for the pump voltage setting (foldout page, position 15).
2. Adjust the tumbler switch so that your approximate
mains voltage appears:
220...240 V: switch display 230 V
100...120 V: switch display 115 V
3. Change the fuse if necessary.
4. Screw on the cover again so that the marking with the
set voltage is on the outside.
The mains cable supplied with the instrument is a 3-core
cable fitted with a plug with an earthing pin. If a different
plug must be used then the yellow/green lead must be
connected to the protective earth. Any break in the earthing
inside or outside the instrument can turn it into a hazard.
When the instrument is opened or if parts of it are removed
then certain components may be live if the instrument is still
connected to the mains. This means that the mains cable
must always be unplugged when certain adjustments are
made or when parts are replaced.
748 DH Sample Changer
The cable should only be plugged in and unplugged when
the instrument is switched off.
5
2.2 Sample Changer setup
2.2 Sample Changer setup
2.2.1 Setting up the basic instrument
Attaching the
control cable:
Fastening the titration head,
sample arm from below:
Important:
Do not lift the sample changer by the sample arm.
Check the delivery immediately on receipt for completeness and transport damage.
Setup
1. Attach control cable to sample arm: insert the white
sleeve with the washer in the cable holder and screw
the holding ring tight (with 1.5 mm Allen key).
Insert cable and secure with clip.
2. Attach and insert the control cable on the rear panel
of the sample changer in the same way.
3. Clip 6.2053.010 cable clamps onto the control cable.
4. Remove splash protection: screw off the 2 sidemounted Phillips screws and carefully pull off plastic
panel.
5. Screw the titration head into the titration head holder
of the sample arm from below (3 mm Allen key)
6. Lead the beaker detector cable through the cable
holder and through the cable clamps to the rear panel
of the sample changer.
7. Connect the beaker detector cable to remote socket
"Auxiliary 1".
8. Reattach splash protection: set place plastic part in
position and screw on again.
6
748 DH Sample Changer
2.2.2 Installation of rinsing accessories
1. Screw 6.1808.050 tubing nozzle for the rinsing tubing
onto the rear panel of the Sample Changer (fold-out
page, Position 16).
2. Attach the rinsing tubing (thin 6.1801.120 PVC tubing)
to the tubing nozzle. Use tubing clamps to attach
tubing firmly.
3. Pull the nut of the small opening of the canister over
the rinsing tubing.
4. Push the other end of the rinsing tubing onto
6.1828.000 connection nipple and screw it tight.
5. Push 6.1812.010 PTFE tubing onto the other end of
the connection nipple (heat up tubing end, hold tubing firmly with abrasive paper) and screw it tight.
6. Screw rinsing tubing onto the rinsing canister and fill
the rinsing canister with rinsing solution (water).
7. Push 6.1801.130 PVC tubing onto the right-hand side
of the Sample Changer (fold-out page, Position 7).
8. Attach other end of tubing to 6.1828.010 tubing nozzle.
9. Screw tubing nozzle onto the waste canister.
2.2 Sample Changer setup
Important
• The waste tubing must not sag.
• Do not seal the canister hermetically (pressure com-
pensation, backwater in the wash beaker!).
• Regularly check the filling levels of the rinsing and
waste canisters!
• The rinsing device is only suitable for use with aqueous solutions.
If you have to rinse with organic solvents then you can
clean the inserts by "immersion in a rinsing beaker".
748 DH Sample Changer
7
2.3 Equipping the titration head
titration head:
2.3 Equipping the titration head
6.1463.000 Macro
titration head:
Beaker detector
M10 screw threads for buret
tips
Stirrer
6.1463.010 Micro
Beaker detector
Stirrer
2.722.0020 Rod stirrer
1. Insert stirrer in titration head.
2. Lead stirrer cable through cable holder and through the
cable clamps to the rear panel of the Sample Changer.
3. Connect cable to stirrer socket "Mixer".
4. Push 6.1909.020 stirrer propeller onto the stirrer from
below.
5. The stirrer speed can be set with the rotary switch on the
rear panel of the Sample Changer.
Electrodes (see also page 27
6.1463.000 macro titration head: electrodes with SGJ 14/15
6.1463.010 micro titration head: micro electrodes, 6 mm di-
ameter.
1. Insert electrode into titration head.
2. Screw electrode cable (at least 2 m long) onto electrode
plug head and lead it through the cable holder and the
cable clamps to the rear panel of the Sample Changer.
3. Plug electrode cable into Titrator.
Buret tips
1. Insert buret tips into titration head and screw tight with
M10 screw threads.
2. Screw 6.1805.XXX tubing connection onto the buret tips.
3. Lead tubing through the tubing holder and the tubing
clamps to the rear panel of the Sample Changer.
4. Connect the other end of the tubing to the dosing unit
outlet. Use 6.1808.000 connection piece for connecting
to the dosing tubing if necessary.
Important
The cable and tubing should be led between the cable/tubing holder and the cable/tubing clamps in a curve so
Built-in buret tips
M10 screw threads for
electrodes or further buret
tips
that they are not subjected to stress when the titration head
is lowered!
Check length of cables and tubings as follows:
• Open Sample Changer window in the titration part of TiNet.
• Press button <Ctrl>.
• Move to "Home" position and lower the sample arm to
working position.
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748 DH Sample Changer
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