wtw inoLab Multi 720 User manual

inoLab
Multi 720
ba75442e01 03/2004
ba75442e
Operating Manual
Measuring Instrument
for pH, Redox, Dissolved Oxygen
and Conductivity
Multi
720

Accuracy when
going to press The use of advanced technology and the high quality stan- dard of our instruments are the result of continuous develop-
ment. This may result in differences between this operating
manual and your instrument.
We cannot guarantee that there are absolutely no errors in
this manual. We are sure you willunderstand that we cannot
accept any legal claims resulting from the data, figures or
descriptions.
Warranty declara-
tion The designated instrument is covered by a warranty of three years from the date of purchase.
The instrument warranty extends to manufacturing faults
that are determined within the period of warranty.
Thewarrantyexcludescomponentsthatarereplacedduring
maintenance such as batteries, etc.
The warranty claim extends to restoring the instrument to
readiness for use but not, however, to any further claim for
damages. Improperhandlingor unauthorized openingof the
instrument invalidates any warranty claim.
To ascertain the warranty liability, return the instrument and
proof of purchase together with the date of purchase freight
paid or prepaid.
Copyright ©Weilheim 2004, WTW GmbH
Reprinting - even as excerpts - is only allowed with the ex-
plicit written authorization of WTW GmbH, Weilheim.
Printed in Germany.

Multi 720 Contents
85
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
1.1 Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
1.2 Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
1.3 Sockets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
1.4 Operating structure. . . . . . . . . . . . . . . . . . . . . . 90
2 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
2.1 Authorized use . . . . . . . . . . . . . . . . . . . . . . . . . 92
2.2 General safety instructions. . . . . . . . . . . . . . . . 92
3 Commissioning. . . . . . . . . . . . . . . . . . . . . . . . . 95
4 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4.1 Switch on the instrument . . . . . . . . . . . . . . . . . 97
4.2 Measuring the pH value/Redox voltage . . . . . . 98
4.2.1 Measuring the pH value . . . . . . . . . . . 100
4.2.2 Measuring the Redox voltage . . . . . . . 101
4.3 Calibrating for pH measurements. . . . . . . . . . 102
4.3.1 AutoCal TEC . . . . . . . . . . . . . . . . . . . . 104
4.3.2 AutoCal DIN . . . . . . . . . . . . . . . . . . . . 106
4.3.3 ConCal . . . . . . . . . . . . . . . . . . . . . . . . 108
4.4 Measuring the dissolved oxygen . . . . . . . . . . 111
4.4.1 Oxygen concentration . . . . . . . . . . . . . 112
4.4.2 Oxygen saturation . . . . . . . . . . . . . . . . 113
4.4.3 Oxygen partial pressure . . . . . . . . . . . 114
4.4.4 AutoRead AR (drift control) . . . . . . . . . 114
4.5 Calibrating for D. O. measurements. . . . . . . . 116
4.5.1 Starting the calibration. . . . . . . . . . . . . 118
4.5.2 Entering the salt content (salinity) . . . . 120
4.6 Measuring the conductivity. . . . . . . . . . . . . . . 121
4.6.1 Conductivity / Specific resistance . . . . 123
4.6.2 Salinity. . . . . . . . . . . . . . . . . . . . . . . . . 124
4.6.3 TDS (total dissolved solids). . . . . . . . . 125
4.6.4 AutoRead AR (Drift control). . . . . . . . . 126
4.7 Determining/setting up the cell constant [C]. . 127
4.7.1 Determining the cell constant
(calibration in control standard). . . . . . 127

Contents Multi 720
86
4.7.2 Setting up the cell constant . . . . . . . . . 130
4.8 Setting up the temperature compensation TC 133
4.9 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 137
4.10 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
5 Maintenance, cleaning, disposal. . . . . . . . . . 143
5.1 Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . 143
5.2 Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
5.3 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
6 What to do if.... . . . . . . . . . . . . . . . . . . . . . . . . 145
6.1 pH system messages. . . . . . . . . . . . . . . . . . . 145
6.2 Oxygen system messages . . . . . . . . . . . . . . . 147
6.3 Conductivity system messages . . . . . . . . . . . 149
6.4 General errors . . . . . . . . . . . . . . . . . . . . . . . . 149
7 Technical Data . . . . . . . . . . . . . . . . . . . . . . . . 151
7.1 General data. . . . . . . . . . . . . . . . . . . . . . . . . . 151
7.2 pH/Redox measurement . . . . . . . . . . . . . . . . 153
7.3 Oxygen measurement . . . . . . . . . . . . . . . . . . 154
7.4 Conductivity measurement. . . . . . . . . . . . . . . 155
8 Lists. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Multi 720 Overview
87
1Overview
The compact inoLab Multi 720 precision measuring instru-
ment lets you perform pH, Redox, D. O., and conductivity
measurements rapidly and reliably. The inoLab Multi 720
provides the highest degree of operating comfort, reliability
and measuring safety for all applications.
The proven OxiCal®and MultiCal®calibration procedures
and special AutoRead function support your work with the
instrument.
Note
The measuring instrument can also be delivered as part of
a set.
Information on this and other accessories is available in the
WTW catalog LABORATORY AND FIELD INSTRUMENTATION or
via the Internet.
1Keypad
2Display
3Sockets
Multi
720
3
2
1

Overview Multi 720
88
1.1 Keypad
1Measuring instrument ON/OFF
2Select measuring mode
3Call up calibration procedure
4Activate/deactivate AutoRead
5Confirm inputs, start AutoRead
6Select measuring mode, increase values,
scroll
7Select measuring mode, reduce values,
scroll
4
3
2
1
7
6
5

Multi 720 Overview
89
1.2 Display
1.3 Sockets
Caution
Only connect probes to the instrument that cannot feed ex-
cessive voltages or currents (> SELV and > circuit with cur-
rent limiter). Almost all commercial electrodes - especially
WTW electrodes - meet these requirements.
On socket 4, use the WTW probe StirrOx G only.
Connectors:
1Dissolved oxygen probe or conductivity measuring cell
2pH/Redox electrode
3Temperature probe
4Stirrer (StirrOx G)
5Reference electrode
6Mains power supply (option)
S
tatus
li
ne
Measured value display
Function and
temperature display
1234
5
6

Overview Multi 720
90
1.4 Operating structure
Thefollowingoverviewdiagram shows which keysyouhave
to press to select between the different measuring modes:
Note
When a D. O. probe or a conductivity measuring cell with
temperature probe is connected, the measuring instrument
recognizes the probe or measuring cell and automatically
switches to the oxygen measuring mode or conductivity
measuring mode last selected. As soon as the probe/mea-
suring cell is disconnected, the instrument switches to the
pH or Redox measuring mode.

Multi 720 Safety
91
2 Safety
This operating manual contains basic instructions that you
must follow during the commissioning, operation and main-
tenance of the instrument. Consequently, all responsible
personnel must read this operating manual before working
with the instrument.
The operating manual must always be available within the
vicinity of the instrument.
Target group This measuring instrument was developed for use in the lab-
oratory.
Thus, we assume that, as a result of their professional train-
ing and experience, the operators will know the necessary
safety precautions to take when handling chemicals.
Symbols used
Caution
indicates instructions that have to be followed to prevent
damage to your instrument.
Warning
indicates instructions that have to be followed to protect
yourself and the instrument from dangerous electrical volt-
age.
Note
Indicates notes that draw your attention to special features.
Note
Indicates cross-references to other documents, e.g. appli-
cation reports, operating manuals of combination elec-
trodes, etc.

Safety Multi 720
92
2.1 Authorized use
This instrument is authorized exclusively for measuring the
pH, Redox, dissolved oxygen and conductivity in the labora-
tory.
Thetechnicalspecifications asgiven inchapter7TECHNICAL
DATA, must be observed. Only the operation and running of
themeasuringinstrumentaccordingtotheinstructionsgiven
in this operating manual is authorized.
Any other use is considered unauthorized.
2.2 General safety instructions
Thisinstrumentisconstructedandtestedincompliancewith
the EN 61010-1 safety regulations for electronic measuring
instruments.
It left the factory in a safe and secure technical condition.
Function and opera-
tional safety The smooth functioning and operational safety of the instru- ment can only be guaranteed if the generally applicable
safety measures and the specific safety instructions in this
operating manual are followed.
The smooth functioning and operational safety of the instru-
ment can only be guaranteed under the climatic conditions
specified in chapter 7 TECHNICAL DATA.
Iftheinstrumentwas transported from acoldenvironmentto
a warm environment, the formation of condensate can lead
to the faulty functioning of the instrument. In this event, wait
until the temperature of the instrument reaches room tem-
perature before putting the instrument back into operation.
Caution
The instrument is only allowed to be opened by personnel
authorized by WTW.