Xylem MULTI-3400 User Manual

Multi 3400i

Operating manual

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pH/Dissolved Oxygen/Conductivity

Measuring Instrument

ba75688e01 01/2007

Accuracy when

going to press

Warranty We guarantee the instrument described for 3 years from the date of

The use of advanced technology and the high quality standard of our
instruments are the result of continuous development. This may result
in differences between this operating manual and your instrument. Al­so, we cannot guarantee that there are absolutely no errors in this man­ual. Therefore, we are sure you will understand that we cannot accept
any legal claims resulting from the data, figures or descriptions.

purchase.
The instrument warranty covers manufacturing faults that are discov­ered within the warranty period. The warranty does not cover compo­nents that are replaced during maintenance work, e.g. batteries.

The warranty claim extends to restoring the instrument to readiness for
use but not, however, to any further claim for damages. Improper han­dling or unauthorized opening of 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 2007, WTW GmbH

Reproduction in whole - or even in part - is prohibited without the ex­press written permission of WTW GmbH, Weilheim.
Printed in Germany.

Multi 3400i List of contents

1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.1 General features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.2 SETs of equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.3 Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4 Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.5 Jack field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.6 Operating structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.1 Authorized use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.2 General safety instructions . . . . . . . . . . . . . . . . . . . . . . . 12

3 Commissioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.1 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2 Initial commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4.1 Switching on the measuring instrument . . . . . . . . . . . . . 15

4.2 pH value / ORP voltage . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.2.1 General information . . . . . . . . . . . . . . . . . . . . . . 16

4.2.2 Measuring the pH value . . . . . . . . . . . . . . . . . . 18

4.2.3 Measuring the ORP voltage . . . . . . . . . . . . . . . 19

4.2.4 pH calibration . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.3 Dissolved oxygen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.3.1 General information . . . . . . . . . . . . . . . . . . . . . . 26

4.3.2 Measuring the D. O. concentration . . . . . . . . . . 27

4.3.3 Measuring the D. O. saturation . . . . . . . . . . . . . 28

4.3.4 AutoRead AR (Drift control) . . . . . . . . . . . . . . . 29

4.3.5 D. O. calibration . . . . . . . . . . . . . . . . . . . . . . . . 30

4.3.6 Salt content correction . . . . . . . . . . . . . . . . . . . 33

4.4 Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.4.1 General information . . . . . . . . . . . . . . . . . . . . . . 34

4.4.2 Measuring the conductivity . . . . . . . . . . . . . . . . 36

4.4.3 Measuring the salinity . . . . . . . . . . . . . . . . . . . . 36

4.4.4 AutoRead AR (Drift control) . . . . . . . . . . . . . . . 37

4.4.5 Determining the cell constant (Calibration in the

control standard) . . . . . . . . . . . . . . . . . . . . . . . . 38

4.5 Calibration intervals (Int 3, Int 4, Int 5) . . . . . . . . . . . . . . 41

4.6 Saving data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

4.6.1 Saving manually . . . . . . . . . . . . . . . . . . . . . . . . 42

4.6.2 Switching on AutoStore (Int 1) . . . . . . . . . . . . . 44

4.6.3 Outputting the data storage . . . . . . . . . . . . . . . . 46

4.6.4 Clearing the memory . . . . . . . . . . . . . . . . . . . . . 52

4.7 Transmitting data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

4.7.1 Data transmission interval (Int 2) . . . . . . . . . . . 53

3

List of contents Multi 3400i

4.7.2 PC/external printer (RS232 interface) . . . . . . . . 55

4.7.3 Remote control . . . . . . . . . . . . . . . . . . . . . . . . . 55

4.8 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

4.9 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

5 Maintenance, cleaning, disposal . . . . . . . . . . . . . . . . . 63

5.1 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

5.2 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

5.3 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6 What to do if... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.1 pH system messages . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.2 Oxi system messages . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

6.3 Conductivity system messages . . . . . . . . . . . . . . . . . . . 68

6.4 General errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

7 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

8 Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

4

Multi 3400i Overview

1Overview

1.1 General features

The compact precision handheld meter Multi 3400i enables you to car­ry out pH measurements, dissolved oxygen (D. O.) measurements and
conductivity measurements quickly and reliably.
The Multi 3400i handheld meter provides the maximum degree of op­erating comfort, reliability and measuring certainty for all applications.

The proven MultiCal

®

and OxiCal® calibration procedures and the pro­cedures to determine/set up the cell constant support you in your work
with the meter. The special AutoRead function enables precise mea­surements.

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1 Keypad

2 Display

3 Jack field

Note

If you need further information or application notes, you can obtain the
following material from WTW:

z Application reports

z Primers

z Safety datasheets.

You will find information on available literature in the WTW catalog or
via the Internet.

5

Overview Multi 3400i

1.2 SETs of equipment

The measuring instrument is also available as part of individual SETs
of equipment.
You will find additional information on this and other accessories in the
WTW catalog or via the Internet.

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Set (sample configuration):

1 Multi 3400i meter, carrying strap with 2 carrying clips, armoring

2 Cond/Oxi beaker with beaker clip

3 pH beaker

4 Stand

5 Plastic beaker

6 Storing solution for pH electrodes

6

Multi 3400i Overview

7 50 ml pH buffer solution, STP 4

8 50 ml pH buffer solution, STP 7

9 Calibration and control standard for conductivity measuring

cells, 50 ml

10 50 ml ELY/G electrolyte solution for D.O. probes

11 50 ml RL/G cleaning solution for D.O. probes

12 WP 90/3 exchange membrane heads for D. O. probes

(3 pieces)

13 SF 300 abrasive film for D.O. probes

14 Conductivity measuring cell

– TetraCon® 325-3 or

– TetraCon® 325

15 pH electrode

– SenTix 41-3 or

– SenTix 41

16 Oxygen sensor

– CellOx 325-3 or

– CellOx 325

17 Operating manual + short operating manual

18 Equipment case

19 Plug-in power supply unit

7

Overview Multi 3400i

1.3 Keypad

STOM

ARRCLCAL

RUN/ENTER

Key functions

M

STO

CAL

RCL

AR

Select the measured variable <M>:

– pH value / ORP voltage

– D. O. concentration / D. O. saturation

– Conductivity / salinity

Save a measured value

<STO>

Switch measuring instrument on/off

<ON/OFF>

Calibrate the currently set measured variable

<CAL>

Display/transmit measured values

<RCL>

Activate/deactivate the AutoRead function

<AR>

Select the measuring mode, increase values,
scroll

<▲ >

Select the measuring mode, decrease values,
scroll

<▼ >

RUN/ENTER

Confirm entries, start AutoRead,
output measured values

<RUN ENTER>

8

Multi 3400i Overview

1.4 Display

Status display

TDS

UpH SalO

S

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8

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Baud

Time

Day.Month No.

Year

Ident

Tref25

LoBat

nLF

1.5 Jack field

8

8.

AutoCal DIN

Tref20

Lin

Cal

AutoCal TEC

8

mV/pH

%

m

mbar

1/

°

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Auto

ARng

mg/l

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cm

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AR

Sal

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TP

RCL

Sensor symbol

Meas. value display

Function and
temperature display

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1 D. O. probe or conductivity measuring cell

2 pH electrode

3 pH temperature sensor

4 Plug-in power supply unit

5 RS232 serial interface

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9

Overview Multi 3400i

1.6 Operating structure

The following overview diagram shows which keys you have to press
to select between the different measuring modes:

Note

When a D. O. probe or a conductivity measuring cell with a 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/measuring cell is disconnected, the instrument switches to the
pH or ORP measuring mode.

10

Multi 3400i Safety

2 Safety

This operating manual contains basic instructions that you must follow
during the commissioning, operation and maintenance of the measur­ing instrument. Consequently, all responsible personnel must read this
operating manual carefully before working with the measuring system.
The operating manual must always be available within the vicinity of the
measuring system.

Target group The measuring instrument was developed for work in the field and in

the laboratory.
Thus, we assume that, as a result of their professional training and ex­perience, the operators will know the necessary safety precautions to
take when handling chemicals.

Safety instructions The individual chapters of this operating manual use the following safe-

ty instruction to indicate various types of danger:

Warning

indicates instructions that must be followed precisely in order to avoid
the possibility of slight injuries or damage to the instrument or the envi­ronment.

Further notes

Note

indicates notes that draw your attention to special features.

Note

indicates cross-references to other documents, e.g. operating manu­als.

2.1 Authorized use

The authorized use of the measuring instrument consists exclusively of
the:

z pH and ORP measurement

z measurement of the oxygen content and

z measurement of the conductivity, salinity and temperature

in the field and laboratory.

The technical specifications as given in chapter 7 T
be observed. Only the operation and running of the measuring instru­ment according to the instructions given in this operating manual is au­thorized. Any other use is considered to be unauthorized.

ECHNICAL DATA must

11

Safety Multi 3400i

2.2 General safety instructions

This instrument is built and inspected according to the relevant guide­lines and norms for electronic measuring instruments (see chapter 7
T

ECHNICAL DATA).

It left the factory in a safe and secure technical condition.

Function and operating

safety

Safe operation If safe operation is no longer possible, the instrument must be taken out

The smooth functioning and operational safety of the measuring instru­ment can only be guaranteed if the generally applicable safety mea­sures and the specific safety instructions in this operating manual are
followed during operation.

The smooth functioning and operational safety of the measuring instru­ment can only be guaranteed under the environmental conditions that
are in specified in chapter 7 T

ECHNICAL DATA.

If the instrument was transported from a cold environment to 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 temperature before putting the instrument
back into operation.

of service and secured against inadvertent operation!
Safe operation is no longer possible if the measuring instrument:

z has been damaged in transport

z has been stored under adverse conditions for a lengthy period of

time

Obligations of the pur-

chaser

z is visibly damaged

z no longer operates as described in this manual.

If you are in any doubt, please contact the supplier of the instrument.

The purchaser of the measuring instrument must ensure that the fol­lowing laws and guidelines are observed when using dangerous sub­stances:

z EEC directives for protective labor legislation

z National protective labor legislation

z Safety regulations

z Safety datasheets of the chemical manufacturers.

12

Multi 3400i Commissioning

3 Commissioning

3.1 Scope of delivery

z Multi 3400i handheld meter

z Plug-in power supply unit

z Operating manual and short operating manual

z 4 batteries, 1.5 V Mignon type AA (in the instrument)

Setting the date and

time

For details of scope of delivery of SETs, see section 1.2 SET

EQUIPMENT and WTW catalog.

3.2 Initial commissioning

Perform the following activities:

z Set the date and time

z Connect the plug-in power supply (optional)

1 Press the <M> key and hold it down.

2 Press the <ON/OFF> key.

The display test appears briefly on the display.

3 Press the <RUN/ENTER> key repeatedly until the date ap-

pears on the display.

4 Set the date of the current day with <▲> <▼>.

5 Confirm with <RUN/ENTER>.

The date (month) flashes in the display.

S OF

6 Set the current month with <▲> <▼>.

7 Confirm with <RUN/ENTER>.

The year appears on the display.

8 Set the current year with <▲> <▼>.

9 Confirm with <RUN/ENTER>.

The hours flash on the display.

10 Set the current time with <▲> <▼>.

11 Confirm with <RUN/ENTER>.

The minutes flash on the display.

12 Set the current time with <▲> <▼>.

13

Commissioning Multi 3400i

13 Confirm with <RUN/ENTER>.

The instrument switches to a measuring mode.

14 Switch the instrument off using <ON/OFF>.

Connecting the

plug-in power supply

You can either operate the measuring instrument with batteries or with
the plug-in power supply. The plug-in power supply supplies the mea­suring instrument with low voltage (12 VDC). This saves the batteries.

Warning

The line voltage at the operating site must lie within the input voltage
range of the original plug-in power supply (see chapter 7 T

TA).

ECHNICAL DA-

Warning

Use original plug-in power supplies only (see
chapter 7 T

ECHNICAL DATA).

2

1

3

14

1 Plug the jack (1) into the socket (2) of the measuring instru-

ment.

2 Connect the original WTW plug-in power supply (3) to an easily

accessible mains socket.

Multi 3400i Operation

4 Operation

4.1 Switching on the measuring instrument

1 Press the <ON/OFF> key.

The display test appears briefly on the display.
After this, the measuring instrument automatically switches to
the measuring mode.

Measuring mode when

switching on

Connected sensor Measuring mode

No sensor or pH/ORP electrode pH or ORP measurement (de-

pending on the last selected set­ting)

D. O. probe or conductivity mea­suring cell

2 sensors of any type Last selected measuring mode

Note

The measuring instrument has an energy saving feature to avoid un­necessary battery depletion. The energy saving feature switches the
measuring instrument off if no key has been pressed for an hour.

The energy saving feature is not active

z if the power is supplied by the plug-in power supply,

z if the AutoStore function is active,

z if the communication cable and a PC with a running communication

program are connected,

z if the printer cable is connected (for external printers).

Last selected measuring mode

AutoRange measure­ment range selection

There are several measuring ranges available for both oxygen and
conductivity measurements. As a rule, the measuring instrument is in
the measuring range with the highest possible resolution. If a measur­ing range is exceeded, AutoRange causes the measuring instrument to
change automatically to the next higher measuring range.
The AutoRange function is always active with oxygen and conductivity
measurements and cannot be switched off.

Note

The measuring ranges for oxygen and conductivity measurements can
be found in chapter 7 T

ECHNICAL DATA.

15

Operation Multi 3400i

4.2 pH value / ORP voltage

4.2.1 General information

Preparatory activities Perform the following preparatory activities when you want to measure:

1 Connect the pH electrode to the measuring instrument.

If necessary, press the <M> key repeatedly until the status dis-
play pH (pH measurement) or U (measurement of the ORP
voltage) appears.

2 Adjust the temperature of the buffer solutions or test solutions,

or measure the current temperature, if you measure without a
temperature sensor.

3 Calibrate or check the measuring instrument with the elec-

trode.

4Using <▲ > <▼>, toggle between the pH or mV measuring

modes.

Note

Incorrect calibration of pH electrodes leads to incorrect measured val­ues. Calibrate regularly before measuring. You can only connect elec­trodes of the NTC30 type or without temperature sensor.

Warning

When connecting an earthed PC/printer, measurements cannot be per­formed in earthed media as incorrect values would result. The RS232
interface is not galvanically isolated.

16

Multi 3400i Operation

Temperature measure-

ment in pH measure-

ments

You can perform pH measurements with or without a temperature sen­sor as well as with the temperature sensor of an oxygen sensor or a
conductivity measuring cell. The measuring instrument recognizes
which sensors are connected and switches automatically to the correct
mode for the temperature measurement.

The following cases are distinguishable.

Temperature sensor Display Mode

pH Cond or

Oxi

yes - TP Automatic with

pH temperature sensor

yes yes TP

- - Manual

-yesTP
flashes

The temperature value of the
second probe (Cond or Oxi) in
the same sample is taken
over for the pH measurement*

* If you do not wish that, you can:

– either disconnect the 2nd sensor and use the manual temperature

input or

– use an electrode with a temperature sensor.

If a temperature sensor is connected, it is indicated on the display by
TP.

Note

When calibrating without a temperature sensor (no TP display indicator
displayed), enter the current temperature of the respective buffer solu­tion manually using the <▲> <▼> keys while keeping the <RUN/EN-

TER> key depressed.

17

Operation Multi 3400i

4.2.2 Measuring the pH value

1 Perform the preparatory activities according to section 4.2.1.

2 Immerse the pH electrode in the test sample.

3 Press the <▲> <▼> keys until pH appears in the status display.

The pH value appears on the display.

AutoRead AR
(Drift control)

TDS

S

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Time

Day.Month No.

Year

Ident

Tref25

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nLF

4 When measuring without a connected temperature sensor:

Options:

z Determine the current temperature using a thermometer

z TP display indicator not displayed, socket for the second

The AutoRead function (drift control) checks the stability of the mea­surement signal. The stability has a considerable impact on the repro­ducibility of the measured values.

pH

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AutoCal DIN

Tref20

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Cal

AutoCal TEC

and, while keeping the <RUN/ENTER> key depressed, en­ter this temperature value with <▲> <▼>.

probe is free:
Connect the second probe (Oxi or Cond) and immerse it in
the same sample. TP flashes, the temperature is automati­cally measured using the second probe.

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Auto

ARng

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S/

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M

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%

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Store

AR

cm

Sal

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/

RCL

TP

18

For identical measurement conditions, the following criteria apply:

Reproducibility Response time

Better than 0.02 > 30 seconds

1 Call up the pH measuring mode with <▲> <▼>.

2 Activate the AutoRead function with <AR>.

The current measured value is frozen (hold function).

Multi 3400i Operation

3 Start AutoRead with <RUN/ENTER>.

AR flashes until a stable measured value is reached.
This measured value is transmitted to the interface.

4 If necessary, start the next AutoRead measurement with

<RUN/ENTER>.

5 To terminate the AutoRead function: Press the <AR> key.

Note

The current AutoRead measurement can be terminated at any time
(accepting the current value) by pressing <RUN/ENTER>.

4.2.3 Measuring the ORP voltage

In conjunction with an ORP electrode, e.g. SenTix ORP, the measuring
instrument can measure the ORP voltage (U) of a solution.

1 Perform the preparatory activities according to section 4.2.1.

2 Submerse the Redox electrode in the sample.

3 Press the <▲> <▼> keys until the U status display appears.

The ORP voltage (mV) of the sample appears on the display.

4 Wait for a stable measured value.

Lin

2

8

Tref20

Cal

pH

U

2

AutoCal DIN
AutoCal TEC

3

4

SalO

mV

%

m

mbar

1/

°

F

8

Auto

ARng

/pH

mg/l

S/

cm

M

cm

°

%

C

Store

AR

cm

Sal

K

/

RCL

TP

TDS

S

8

1

Baud

Time

Day.Month No.

Year

Ident

Tref25

LoBat

nLF

Note

ORP electrodes are not calibrated. However, you can check ORP elec­trodes using a test solution.

19

Operation Multi 3400i

4.2.4 pH calibration

Why calibrate? pH electrodes age. This changes the asymmetry (zero point) and slope

of the pH electrode. As a result, an inexact measured value is dis­played. Calibration determines the current values of the asymmetry
and slope of the electrode and stores them in the measuring instru­ment. Thus, you should calibrate at regular intervals.

When to calibrate? z After connecting another electrode

z When the sensor symbol flashes:

– after the calibration interval has expired

– after a voltage interruption, e. g. after changing the batteries

AutoCal TEC is specially matched to the WTW technical buffer solutions as a fully au-

tomatic two-point calibration. The buffer solutions are automatically
recognized by the measuring instrument. Depending on the instrument
setting (see section 4.8 C

ONFIGURATION), the instrument displays the

relevant buffer nominal value or the current electrode voltage in mV.
The calibration can be terminated after the first buffer solution. This cor­responds to a single-point calibration. To do this, the instrument uses
the Nernst slope (-59.2 mV/pH at 25 °C) and determines the asymme­try of the electrode.

AutoRead The calibration procedure automatically activates the AutoRead func-

Displaying the calibra-

tion data

Printing the

calibration protocol

tion.
The current AutoRead measurement can be terminated at any time
(accepting the current value) by pressing <RUN/ENTER>.

You can view the data of the last calibration on the display. The pro­ceeding is described on page 48.

The calibration record contains the calibration data of the current cali­bration. You can transmit the calibration protocol to a printer via the se­rial interface (see O

INTERFACE, page 51).

UTPUTTING THE CALIBRATION PROTOCOL ON THE

Note

You can automatically print a calibration record after the calibration. To
do so, connect a printer to the interface according to section 4.7.2 be­fore calibrating. After a valid calibration, the record is printed.

20

Multi 3400i Operation

Sample printout:

CALIBRATION PROTOCOL

02.03.01 14:19
Device No.: 12345678
Calibration pH
Cal time: 01.03.01 / 15:20
Cal interval: 7d
AutoCal TEC Tauto
Buffer 1 2.00
Buffer 2 4.01
Buffer 3 7.00 *
Buffer 4 10.00
C1 184.1 mV 25.0°C
C2 3.0 mV 25.0°C
S1 -59.4 mV/pH
ASY1 - 4 mV
Probe: +++

Calibration evaluation After calibrating, the measuring instrument automatically evaluates the

calibration. The asymmetry and slope are evaluated separately. The
worst evaluation appears on the display.

Display Asymmetry

[mV]

-15 ... +15 -60.5 ... -58

-20 ... +20 -58 ... -57

-25 ... +25 -61 ... -60.5

-30 ... +30 -62 ... -61

Clean the electrode according
to the electrode operating
manual

Slope
[mV/pH]

or

-57 ... -56

or

-56 ... -50

E3

Eliminate the error according to
chapter 6 W

HAT TO DO IF...

< -30 or
> 30

... -62 or
... -50

21

Operation Multi 3400i

Preparatory activities

AutoCal TEC For this procedure, use any two WTW technical buffer solutions (pH

1 Connect the pH electrode to the measuring instrument.

If necessary, press the <M> key repeatedly until the status dis-
play pH (pH measurement) or U (measurement of the ORP
voltage) appears.

2 Keep the buffer solutions ready.

3 Adjust the temperature of the solution and measure the current

temperature if the measurement is made without the use of a
temperature sensor (the TP display indicator is missing from
the display).

values at 25 °C: 2.00 / 4.01 / 7.00 / 10.01).

Note

The calibration for pH 10.01 is optimized for the WTW technical buffer
solution TEP 10 Trace or TPL 10 Trace. Other buffer solutions can lead
to an erroneous calibration. The correct buffer solutions are given in the
WTW catalog or in the Internet.

Note

The buffer solutions are automatically recognized by the measuring in­strument. Depending on the instrument setting (see section

4.8 C

ONFIGURATION), the instrument displays the relevant buffer nomi-

nal value or the current electrode voltage in mV.

Starting the calibration

Note

Skip the steps 2 and 7 if you use a pH electrode with temperature sen­sor or the temperature sensor of a conductivity measuring cell or a D.
O. probe.

1 Press the <CAL> key. The Ct1 display and the function display

AutoCal TEC appears. The sensor symbol displays the evalu­ation of the last calibration (or no sensor symbol in the delivery
state or after the measurement parameter has been reset).

22

Multi 3400i Operation

TDS

S

C

1

Baud

Time

Day.Month No.

Year

Ident

Tref25

LoBat

nLF

2 If required, enter the temperature of the first buffer solution,

while keeping the <RUN/ENTER> key depressed, using <▲>
<▼>.

3 Immerse the pH electrode in the first buffer solution.

4 Press the <RUN/ENTER> key.

The AR display indicator flashes.
The electrode voltage (mV) or the buffer nominal value ap­pears on the display. Example:

7

Baud

Time

Day.Month No.

Year

Ident

Tref25

LoBat

nLF

pH

OU

Sal

/pH

mV

%

mg/l

m

S/

cm

cm

M

t

2

8

AutoCal DIN

Tref20

Cal

Lin

AutoCal TEC

3

22

0

AutoCal DIN

Tref20

Cal

Lin

AutoCal TEC

mbar

1

Sal

cm

1/

TP

°

K

%

/

°

C

F

8

4

44

Store

Auto

ARng

AR

RCL

TDSTDS

mV

SS

cm

cm

TP

°

°

C

F

88

Store

Auto

ARng

AR

RCL

7

11

Baud

Time

Day.Month No.

Year

Ident

Tref25

LoBat

nLF

Lin

0

0

Tref20

Cal

pHpH

OO UpHUpH SalSal

03

AutoCal DIN
AutoCal TEC

mbarmbar

mV/pHmV/pH

%%

mm

1/1/

°

Auto

ARng

F

mg/lmg/l

S/S/

°

cmcm

MM

cm

%%

C

Store

ARAR

AR

//

cm

SalSal

KK

RCL

TP

5 When the measured value is stable, Ct2 appears.

Lin

t

8

Tref20

Cal

pH

OU

2

2

4

AutoCal DIN

AutoCal TEC

Sal

mV

%

m

mbar

1/

°

F

8

Auto

ARng

/pH

mg/l

S/

cm

M

cm

°

%

C

Store

AR

cm

Sal

K

/

RCL

TP

23

TDS

S

C

1

Baud

Time

Day.Month No.

Year

Ident

Tref25

LoBat

nLF

Note

At this point, the AutoCal TEC calibration can be terminated with <M>.
This corresponds to a single-point calibration. To do this, the instru-
ment uses the Nernst slope (-59.2 mV/pH at 25 °C) and determines the
asymmetry of the electrode.

Operation Multi 3400i

6 Thoroughly rinse the electrode with distilled water.

7 If required, enter the temperature of the first buffer solution,

while keeping the <RUN/ENTER> key depressed, using <▲>
<▼>.

8 Immerse the pH electrode in the second buffer solution.

9 Press the <RUN/ENTER> key.

The AR display indicator flashes.
The electrode voltage (mV) or the buffer nominal value ap­pears on the display. Example:

TDS

mV

S

1

1

Baud

Time

Day.Month No.

Year

Ident

Tref25

LoBat

nLF

10 When the measured value is stable, AR disappears. The value

of the slope (mV/pH) appears on the display. The probe symbol
shows the evaluation of the current calibration.

TDS

22

0

Tref20

Lin

44

AutoCal DIN

Cal

AutoCal TEC

pH

OU

S

9

1

Time

Day.Month

Year

LoBat

5

Baud

No.

Ident

Tref25
nLF

Tref20

Lin

S

Cal

4

L

AutoCal DIN
AutoCal TEC

cm

TP

°

°

C

F

88

Store

Auto

ARng

AR

RCL

Sal

mV/pH

%

mg/l

m

S/

cm

cm

M

mbar

Sal

cm

1/

TP

°

K

%

/

°

C

F

O

Store

Auto

ARng

AR

RCL

TDS

S

4

1

Time

Day.Month No.

Year

Tref25

LoBat

nLF

Baud

Ident

Lin

08

0

Tref20

Cal

pHpH

OO UpHUpH SalSal

14

AutoCal DIN
AutoCal TEC

mbarmbar

mV/pHmV/pH

%%

mm

1/1/

°

F

Auto

ARng

mg/lmg/l

S/S/

MM

cm

°

%%

C

Store

ARAR

AR

cmcm

cmcm

SalSal

TP

KK

//

RCL

24

11 Press the <RUN/ENTER> key. The value of the asymmetry

(mV) appears on the display.

Multi 3400i Operation

No.

Lin

0

8

Tref20

Cal

pH

OU

2

S

AutoCal DIN
AutoCal TEC

Sal

mV

%

m

mbar

1/

°

F

YA

Auto

ARng

mg/l

S/

cm

M

cm

°

%

C

Store

AR

cm

Sal

K

/

RCL

TP

TDS

S

6

1

Baud

Time

Day.Month

Year

Ident

Tref25

LoBat

nLF

12 Switch to the measuring mode with <M>.

25

Operation Multi 3400i

4.3 Dissolved oxygen

4.3.1 General information

Note

D. O. measurements with the Multi 3400i can only be carried out using
a CellOx 325 or StirrOx G D. O. probe. The stirrer of the StirrOx G
D. O. probe has to be supplied with voltage separately using the
NT/pH Mix 540 power supply.

You can measure the following variables:

z D. O. concentration

z D. O. saturation

The measuring instrument is supplied with the following functions:

z AutoRange (automatic switchover of the measurement range),

z The AutoRead function (drift control) for checking the stability of the

measurement signal. This ensures the reproducibility of the measur­ing signal. For details of how to switch the AutoRead function on/off,
see page 29.

Warning

When connecting an earthed PC/printer, measurements cannot be per­formed in earthed media as incorrect values would result.
The RS232 interface is not galvanically isolated.

Preparatory activities Perform the following preparatory activities when you want to measure:

1 Connect the D. O. probe to the measuring instrument. The in-

strument automatically switches over to D. O. measurement
(O

status display).

2

If the D. O. probe is already connected, press the <M> repeat-
edly until the O

status display appears.

2

2 Calibrate or check the measuring instrument with the sensor.

How to calibrate is described in section 4.3.5 from page 20.

3 Use <▲> <▼> to toggle between the measuring modes, D. O.

concentration (mg/L) and D. O. saturation (%).

Note

Incorrect calibration of D. O. probes will result in incorrect
measured values. Calibrate at regular intervals.

Temperature sensor The D. O. probe has an integrated temperature sensor that always

measures the current temperature of the test sample.

26