Metrohm 781 User Manual

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780 pH Meter / 781 pH/Ion Meter

Manual

8.781.8002EN / 2014-07-31

Metrohm AG CH-9100 Herisau Switzerland Phone +41 71 353 85 85 Fax +41 71 353 89 01 info@metrohm.com www.metrohm.com

780 pH Meter / 781 pH/Ion Meter

Program Version 5.780.0020 und 5.781.0020

8.781.8002EN / 2014-07-31

Manual

jb/ebe

Teachware Metrohm AG CH-9100 Herisau teachware@metrohm.com

Although all the information given in this documentation has been checked with great care, errors cannot be entirely excluded. Should you notice any mistakes please send us your comments using the address given above.

Documentation in additional languages can be found on

http://documents.metrohm.com.

Contents

780/781 pH/Ion Meter, Manual

Table of contents

1 Introduction .......................................................... 1

1.1 Instrument description ................................................................................. 1

1.2 Parts and controls ........................................................................................ 3

1.3 Information about this Manual ..................................................................... 5

1.3.1 Notation and pictograms ......................................................................... 5

1.4 Safety information ........................................................................................ 6

1.4.1 Electrical safety ........................................................................................ 6

1.4.2 General handling rules ............................................................................. 6

2 Installation ........................................................... 7

2.1 Instrument setup .......................................................................................... 7

2.1.1 Packaging ................................................................................................. 7

2.1.2 Checks ...................................................................................................... 7

2.1.3 Location .................................................................................................... 7

2.2 Connecting the accessories ........................................................................ 8

2.3 Connecting optional devices ....................................................................... 9

2.3.1 Connecting the 801 Magnetic Stirrer ....................................................... 9

2.3.2 Connecting the 802 Rod Stirrer ..............................................................10

2.3.3 Connecting a Dosimat Plus (only 781) ..................................................11

2.3.4 Connecting a sample changer ...............................................................12

2.3.5 Connecting a printer ...............................................................................13

2.3.6 Connecting a computer .........................................................................15

2.4 Connecting the electrodes and sensors ................................................... 16

2.5 Mains connection ....................................................................................... 17

2.6 Switch on .................................................................................................... 17

2.7 Initial configuration .................................................................................... 18

3 Short operating tutorial ..................................... 19

3.1 pH measurement ........................................................................................ 19

3.1.1 Requirements .........................................................................................19

3.1.2 Preparations ...........................................................................................19

3.1.3 pH calibration .........................................................................................20

3.1.4 pH measurement ....................................................................................22

3.2 Determination of an ion concentration (only 781: Conc mode) ............... 23

3.2.1 Requirements .........................................................................................23

3.2.2 Preparations ...........................................................................................23

3.2.3 Calibrating the fluoride ISE .....................................................................24

3.2.4 Direct measurement of fluoride ..............................................................28

4 Operation ........................................................... 31

4.1 The keypad ................................................................................................. 31

4.2 Operating concept ..................................................................................... 32

4.3 All key functions at a glance ...................................................................... 33

4.4 Operating principles .................................................................................. 38

4.4.1 Configuration and method parameters .................................................38

4.4.2 Editing menu entries ..............................................................................38

4.4.3 Entering text ............................................................................................39

Contents

780/781 pH/Ion Meter, Manual

5 Configuration ..................................................... 41

5.1 Report ......................................................................................................... 42

5.2 Printing out measured values .................................................................... 44

5.3 Storing measured values ........................................................................... 47

5.4 Auxiliaries ................................................................................................... 48

5.5 Monitoring .................................................................................................. 51

5.6 Peripheral units .......................................................................................... 52

5.7 RS232 settings ........................................................................................... 54

6 Methods / Parameters ........................................ 55

6.1 Method management ................................................................................. 55

6.2 pH measurement (pH mode) ..................................................................... 56

6.2.1 Measuring parameters ........................................................................... 56

6.2.2 Calibration parameters........................................................................... 58

6.2.3 Limits pH ................................................................................................ 62

6.2.4 Limits T ................................................................................................... 62

6.2.5 Plot parameters ...................................................................................... 63

6.2.6 Preselections .......................................................................................... 63

6.2.7 Electrode test ......................................................................................... 64

6.3 Temperature measurement (T mode) ........................................................ 65

6.3.1 Measuring parameters ........................................................................... 65

6.3.2 Limits T ................................................................................................... 66

6.3.3 Plot parameters ...................................................................................... 67

6.3.4 Preselections .......................................................................................... 67

6.4 Potential measurement (U mode) .............................................................. 68

6.4.1 Measuring parameters ........................................................................... 68

6.4.2 Limits U................................................................................................... 69

6.4.3 Plot parameters ...................................................................................... 70

6.4.4 Preselections .......................................................................................... 70

6.5 Direct ion measurement (781 only: Conc mode) ...................................... 71

6.5.1 Type of measurement ............................................................................ 71

6.5.2 Ion parameters ....................................................................................... 71

6.5.3 Measuring parameters ........................................................................... 72

6.5.4 Calculation parameters .......................................................................... 74

6.5.5 Calibration parameters........................................................................... 75

6.5.6 Limits Conc ............................................................................................ 77

6.5.7 Limits T ................................................................................................... 78

6.5.8 Plot parameters ...................................................................................... 78

6.5.9 Preselections .......................................................................................... 79

6.6 Standard and sample addition (781 only: Conc mode) ............................ 80

6.6.1 Standard / Sample addition ................................................................... 80

6.6.2 Preselections .......................................................................................... 83

7 Various functions ............................................... 85

7.1 Calibration and addition/subtraction data ................................................ 85

7.1.1 pH calibration data ................................................................................. 85

7.1.2 Conc calibration data (781 pH/Ion Meter only) ..................................... 89

7.1.3 Addition/Subtraction data (781 pH/Ion Meter only) ............................... 93

7.2 Reports ....................................................................................................... 96

Contents

780/781 pH/Ion Meter, Manual

7.2.1 Arrangement of a report .........................................................................98

7.2.2 Report identification ...............................................................................99

7.2.3 Measuring point report ...........................................................................99

7.2.4 Calibration report ..................................................................................101

7.2.5 Result report (781 pH/Ion Meter only) ..................................................102

7.2.6 Configuration report .............................................................................103

7.2.7 Parameter report ..................................................................................104

7.2.8 Measured values memory report .........................................................105

7.2.9 User method report ..............................................................................106

7.3 Measured values memory ........................................................................ 107

7.3.1 Save measured values .........................................................................107

7.3.2 Print measured values ..........................................................................107

7.3.3 Show measured values ........................................................................108

7.4 Limit monitoring ....................................................................................... 109

7.4.1 Uses ......................................................................................................109

7.4.2 How it functions ....................................................................................110

7.5 Setup ........................................................................................................ 111

7.5.1 Locking .................................................................................................111

7.5.2 Input assignment ..................................................................................112

7.5.3 Graphics ...............................................................................................112

8 Troubleshooting – Messages – Maintenance .. 113

8.1 Troubleshooting ....................................................................................... 113

8.2 Messages ................................................................................................. 115

8.3 QM support............................................................................................... 120

8.4 Validation .................................................................................................. 122

8.4.1 Electronic tests .....................................................................................122

8.4.2 Wet tests ...............................................................................................123

8.4.3 pH/Ion Meter maintenance...................................................................123

8.5 Diagnosis .................................................................................................. 124

8.6 pH electrode test ...................................................................................... 126

8.6.1 Preparations .........................................................................................126

8.6.2 Procedure .............................................................................................127

8.6.3 Results ..................................................................................................129

8.6.4 Messages and measures .....................................................................131

8.6.5 Care and maintenance of pH glass electrodes ...................................132

9 Annex ................................................................ 135

9.1 Technical data .......................................................................................... 135

9.1.1 Measuring modes ................................................................................135

9.1.2 Measuring inputs ..................................................................................135

9.1.3 Measuring input specifications ............................................................136

9.1.4 Interfaces ..............................................................................................136

9.1.5 Power supply ........................................................................................136

9.1.6 Safety specifications ............................................................................137

9.1.7 Electromagnetic compatibility (EMC) ..................................................137

9.1.8 Ambient temperature ............................................................................137

9.1.9 Reference conditions ...........................................................................137

9.1.10 Dimensions ...........................................................................................137

9.2 Evaluation ................................................................................................. 138

III

Contents

780/781 pH/Ion Meter, Manual

9.2.1 pH calibration ....................................................................................... 138

9.2.2 Calibration for ion measurements ........................................................ 142

9.2.3 Addition method ................................................................................... 143

9.3 Menu structures ....................................................................................... 144

9.3.1 Instrument configuration ...................................................................... 144

9.3.2 Method parameters in the pH mode ................................................... 146

9.3.3 Method parameters in the T mode ...................................................... 147

9.3.4 Method parameters in the U mode...................................................... 147

9.3.5 Method parameter in the Conc mode ................................................. 148

9.4 Stored buffer series ................................................................................. 150

9.5 Remote box .............................................................................................. 156

9.5.1 Pin occupancy of the remote connection of the Remote box ............. 156

9.5.2 Functions of the individual remote lines .............................................. 157

9.6 Accessories .............................................................................................. 158

9.7 Warranty (guarantee) ............................................................................... 160

10 Index ................................................................. 163

Contents

780/781 pH/Ion Meter, Manual

List of illustrations

Fig. 1: 781 pH/Ion Meter connected to 801Magnetic Stirrer .................................................... 1

Fig. 2: Front view of the 780 pH Meter or 781 pH/Ion Meter .................................................... 3

Fig. 3: Rear view of the 780 pH Meter or 781 pH/Ion Meter ..................................................... 4

Fig. 4: Possible arrangements for mounting the base plate .................................................... 8

Fig. 5: Attaching the support rod and base plate..................................................................... 8

Fig. 6: Ready-mounted pH/ISE measuring system .................................................................. 9

Fig. 7: 780 pH Meter / 781 pH/Ion Meter – 801 Magnetic stirrer .............................................. 9

Fig. 8: 780 pH Meter / 781 pH/Ion Meter – 802 Rod stirrer .................................................... 10

Fig. 9: 781 pH/Ion Meter – Dosimat Plus ................................................................................ 11

Fig. 10: 781 pH/Ion Meter – Dosimat Plus – Sample changer ............................................... 12

Fig. 11: 780 pH Meter / 781 pH/Ion Meter – Printer ............................................................... 13

Fig. 12: Connecting sensors ................................................................................................... 16

Fig. 13: Remote outputs in limit monitoring .......................................................................... 110

Fig. 14: Diagram showing changes in potential during an electrode test ........................... 129

Fig. 15: Theoretical U/pH relationship ................................................................................ 138

Fig. 16: 3-Point pH calibration .............................................................................................. 139

Fig. 17: Connections of the optional 6.2148.010 Remote box ............................................. 156

Fig. 18: Pin occupancy at remote interface .......................................................................... 156

1 Introduction

780/781 pH/Ion Meter, Manual

780 pH Meter

781

pH/Ion Meter

Electrodes in Potentiometry

Application Notes

Application

Bulletins

781 pH/Ion Meter

780 pH Meter,

781 pH/Ion Meter

780 pH Meter

Conc

mode

1 Introduction

This Manual provides you with a comprehensive overview of the installation, working principles and operation of the

measuring modes of the 780 pH Meter are concerned (pH, temperature and potential) and their operation in these modes is also identical, the Manuals for both have been incorporated in a single document. The special measuring mode of the 781 pH/Ion Meter – the measurement of concentration – is, like the other measuring modes, described in separate sections. These sections, which apply only to the operation of the 781 pH/Ion Meter, are marked accordingly.

Information about the use of Metrohm pH or ion-selective electrodes can be found in the appropriate leaflet and the ISE Manual that is included with the electrode.

Additional theoretical principles can be found in the Metrohm Monograph "

. As these two instruments are identical as far as the three

and

You can also request our descriptions of applications involving pH and ISE measurements in the form of

Internet under

from your local Metrohm agency or download them from the

www.metrohm.com.

Fig. 1: 781 pH/Ion Meter connected to 801Magnetic Stirrer

1.1 Instrument description

and

Both instrument versions, the are used for measuring pH, temperature and potential reliably and at high resolution. The having an additional operating mode for the potentiometric determination of the concentration by using ion-selective electrodes (

Both instruments have comprehensive monitoring functions (for calibration, validation and service intervals), diagnostic functions and an au-

differs from the

and the

1.1 Instrument description

780/781 pH/Ion Meter, Manual

781 pH/Ion Meter

Conc mode

calibration

standard addition

tomatic pH electrode test. Up to 100 values can be stored in the memory together with the most important additional data; these can be viewed and outputted as a report. All the parameter settings for a measuring mode can be permanently stored as a method.

All stored information (measured values, configuration, parameters, etc.) can be transmitted via the RS 232 interface to a printer or computer for output as a report.

Both instruments have the following features:

• Dot-matrix display for both the continuous display of the measured

value and for showing the user dialog.

• High-impedance measuring input for pH, redox or ISE sensors, a

connection for a separate reference electrode and an input for temperature sensors (Pt1000 or NTC).

• MSB connection (Metrohm Serial Bus) for a stirrer and for a

Dosimat Plus.

• RS 232 connection for a serial printer or a computer.

• A connection for an external keyboard or a barcode reader.

The

has an additional

which allows the measurement of the concentration by using ion-selective electrodes, either directly after calibration or by standard or sample addition methods. Such a

can be carried out either manually or automatically. In the latter method a standard solution is added automatically by a Dosimat Plus included in the system. The calibration concentrations or the standard additions are calculated automatically according to the given conditions and these are added with great accuracy.

1 Introduction

780/781 pH/Ion Meter, Manual

1 LCD display

3 Main function keys

2 On/Off key

4 Input, navigation and

function keys

1.2 Parts and controls

Fig. 2: Front view of the 780 pH Meter or 781 pH/Ion Meter

Key for switching the instrument on and off

Each key has several functions; the particular function depends on the work status of the instrument

1.2 Parts and controls

780/781 pH/Ion Meter, Manual

5 Connection for potentiometric electrodes

RS232 interface

6 Connection for separate reference

electrode

Barcode reader/ Keyboard connection

7 Serial number

12V power connection

8 Connection for temperature sensor

Grounding connection

MSB connection

, directly or via

Fig. 3: Rear view of the 780 pH Meter or 781 pH/Ion Meter

pH, ISE, redox or silver electrodes

Connection for printer or PC with built-in or separate reference electrode; socket type F

4 mm socket type B

Pt1000 or NTC, for connection with two 2 mm B-plugs; 6.2103.130 and 6.2103.140 Adapters are included for use with 4 mm banana plugs

(Metrohm Serial Bus) for connecting a stirrer and/or Dosimat Plus the optional Remote Box (6.2148.010)

For measurements in grounded solu-

tions, grounding of the instrument

may be advantageous to avoid inter-

ferences; 4 mm socket type B

1 Introduction

780/781 pH/Ion Meter, Manual

Menu item, parameter or input value

<MODE>

Key

Operating element

Danger

Warning Attention

Information

TIP !

TIP

1.3 Information about this Manual

Please study this Manual carefully before you start to use the instrument. The Manual contains information and warnings that must be observed by the user in order to guarantee the safe use of the instrument.

1.3.1 Notation and pictograms

The following notations and pictograms (symbols) are used in this Manual:

Range

This symbol indicates a possible risk of death or injury if the given information is not properly observed.

This symbol indicates a possible risk of damage to the instrument or its components if the given information is not properly observed.

This symbol indicates important information. Please read it carefully before you continue.

This symbol indicates additional information and tips.

This symbol indicates information that may be of particular use to you.

1.4 Safety information

780/781 pH/Ion Meter, Manual

Warning!

ng with water or other solutions in the immediate vicinity of

1.4 Safety information

This instrument should only be used in accordance with the information given in this Manual.

1.4.1 Electrical safety

Please observe the following guidelines:

• Only qualified Metrohm technicians should carry out service work

on electronic components.

• Do not open the pH/Ion Meter housing. This could destroy the

pH/Ion Meter. Inside the housing there are no components that the user can service or exchange.

Electrical safety when handling the 780 pH Meter and the 781 pH/Ion Meter is guaranteed within the framework of the IEC 61010 Standard. The following points must be observed:

Please make sure that the external power supply is always kept dry. Protect it against direct liquid contact .

Electronic components are sensitive to electrostatic charges and can be destroyed by a discharge. Always switch off the pH/Ion Meter before making or breaking electrical connections on the rear panel of the instrument.

1.4.2 General handling rules

Handling solutions

When worki the pH/Ion Meter please avoid excessive liquid splashes on the instrument housing or power supply. Any such splashes must be removed as quickly as possible in order to prevent the liquid from entering the instrument or the power supply.

2 Installation

780/781 pH/Ion Meter, Manual

2 Installation

2.1 Instrument setup

2.1.1 Packaging

The 780/781 pH/Ion Meter and its specially packed accessories are supplied in very protective special packaging made of shock absorbing polypropylene foam. Please store this packaging in a safe place; it is the only way in which the safe transport of the instrument can be guaranteed. Should you wish to dispose of it please consider suitable disposal or recycling processes.

2.1.2 Checks

Please check that the delivery is complete and undamaged immediately on receipt (compare with delivery note and list of accessories given in Section 9.6).

2.1.3 Location

Place the instrument on a suitable vibration-free laboratory bench, protected from corrosive atmospheres and contact with chemicals.

2.2 Connecting the accessories

780/781 pH/Ion Meter, Manual

stand base

2.2 Connecting the accessories

Both the stand for attaching the stirrer, clamping ring and electrode holder as well as the pH/Ion Meter itself can be mounted on the supplied

You can chose between the arrangements shown in Fig. 4 to suit your own particular working preference.

Fig. 4: Possible arrangements for mounting the base plate

Versions A and B are intended for mounting an 801 Magnetic stirrer on the left- and right-hand side of the pH/Ion Meter respectively. If you frequently work without such a permanently attached stirrer then you can mount the base plate so that you have space for the sample vessel directly in front of the support rod (versions

Attach the base plate with the screws provided as shown in Fig. 5. The rubber feet included prevent the system from slipping about on the work bench and should therefore be stuck on to the base plate.

and D).

Fig. 5: Attaching the support rod and base plate

2 Installation

780/781 pH/Ion Meter, Manual

801 Magnetic Stirrer

802 Rod Stirrer

804 Ti-Stand

Dosimat Plus

801 Magnetic Stirrer

2.3 Connecting optional devices

Devices which are to be remotely controlled from the pH/Ion Meter (e.g. Metrohm stirrers or Dosimat Plus devices) are connected to MSB connection

6.2148.010 Remote Box (e.g.

2.3.1 Connecting the 801 Magnetic Stirrer

Mount the magnetic stirrer on the support rod before attaching the clamping ring (6.2013.010) and the electrode holder (6.2021.020). Further details are given in the corresponding Manual.

For example, the ready-mounted system could look like this:

. This can be carried out either directly (

with

) or via the optionally available

Fig. 6: Ready-mounted pH/ISE measuring system

The is connected to it directly:

Fig. 7: 780 pH Meter / 781 pH/Ion Meter – 801 Magnetic stirrer

is controlled via MSB connection 9. The stirrer

2.3 Connecting optional devices

780/781 pH/Ion Meter, Manual

802 Rod Stirrer

804 Ti Stand,

2.3.2 Connecting the 802 Rod Stirrer

The connected directly to the pH/Ion Meter. This is done by plugging the MSB connection cable of the 804 Ti Stand into MSB connection pH/Ion Meter:

Fig. 8: 780 pH Meter / 781 pH/Ion Meter – 802 Rod stirrer

, in combination with the

can also be

of the

2 Installation

780/781 pH/Ion Meter, Manual

Controlled addition of standard or sample solutions

781 pH/Ion Meter

865

876

DOS

Furthermore, the Dosimat Plus

“HOLD”

2.3.3 Connecting a Dosimat Plus (only 781)

For automatic calibration as well as for the addition of standard or samples in the Conc mode with the and available 6.2148.010 Remote Box. Control is carried out via the

6.2141.350 cable:

Dosimat Plus devices can be connected via the separately

the Metrohm

Fig. 9: 781 pH/Ion Meter – Dosimat Plus

If a Dosimat Plus is used then a stirrer is normally also required. This is then connected directly with the MSB connection of the 6.2148.010 Remote Box (stirrer: 801 or 802+804).

Please note that for the standard addition the mode “ the Dosimat Plus. The activation pulse must be activated on the pH Meter as well as the Dosimat Plus. must be in the status pressing the “Go” key once (check: the display of the Dosimat Plus shows

in the top right-hand corner).

. You can set the status to

” is set on

2.3 Connecting optional devices

780/781 pH/Ion Meter, Manual

Compact Sample Changer 869

2.3.4 Connecting a sample changer

For simple automated measurement of several samples and standards with the pH/Ion Meter the Metrohm be connected. Communication takes place via the 6.2148.010 Remote Box, i.e. the measurements are triggered by the sample changer and their completion is also transmitted by the pH/Ion Meter via the remote connection. The individual steps for processing a series of samples or standards are defined as a method in the sample changer.

Please note that when work is carried out in this way that no sample data is transferred between the sample changer and the pH/Ion Meter. This means that the assignment of the report outputs is only possible by using the consecutive run number (see Section 5.4).

The connection of a Compact Sample Changer 869 and a Dosimat Plus 865 for automatic calibration with standard addition is described here as an example. A detailed description of how to program a method in the Compact Sample Changer 869 is given in the corresponding Manual of the instrument.

can

Fig. 10: 781 pH/Ion Meter – Dosimat Plus – Sample changer

2 Installation

780/781 pH/Ion Meter, Manual

2.3.5 Connecting a printer

A printer with a serial or parallel interface can be connected to the RS232 interface for printing out reports.

The connection of the 40-character Custom DP40-S4N printer (Metrohm ordering number: 2.140.0200) with the serial 6.2134.110 Cable is described as an example:

Fig. 11: 780 pH Meter / 781 pH/Ion Meter – Printer

The transmission parameters for the pH/Ion Meter and the printer must be the same. On the pH/Ion Meter these are set under

CONFIG/peripheral units/character set: (see Section 5.6)

and under

CONFIG/RS232 settings (see Section 5.7).

These settings and other possible printer connections are given in the following table. If you wish to connect a printer which is not mentioned here then make sure that it emulates the Epson mode or uses the international character set according to IBM Standard Table 437 and IBMcompatible graphics control characters.

Please observe the paper feed settings after each report printout (see Section 5.1).

The settings for graph sizes in the printer output are accessible in the setup of the pH/Ion Meter and are described in Section 7.5.3. This can particularly be necessary for single sheet printers (i.e. HP Desk Jet).

2.3 Connecting optional devices

780/781 pH/Ion Meter, Manual

IDP-560 EMULATION

GERMANY also for Swedish.

Seiko

6.2134.110

Character Set: Seiko

Handshake: HWs

none

Handshake: HWs

Character Set: Epson

Handshake: HWs

HP Desk Jet

2.145.0330

Character Set: HP

see Printer Manual

1 2 3 4 5 6 7 8 9

SSW1

1 2 3 4 5 6 7

A4 Paper

Printer Cable 780/781 settings Printer settings

Custom DP40-S4N

DPU-414

Citizen iDP562 RS

6.2134.110 Character Set: Citizen Baud Rate: 9600 Data Bit: 8 Stop Bit: 1 Parity: none Handshake: HWs

Baud Rate: 9600 Data Bit: 8 Stop Bit: 1 Parity: none

6.2134.050 Character Set: Citizen Baud Rate: 9600 Data Bit: 8 Stop Bit: 1 Parity: none

FONT MAP = ENGLAND * PRINT = REVERSE LITTLE CR CODE = VOID CR AFTER B. FULL = VOID CR ON B. EMPTY = VALID BUFFER 1K BYTE BAUD RATE = 9600 PROTOCOL = 8,N,1 FLOW CONTROL CTS-RTS

(*) FRANCE also for Italian, Spanish and Portuguese,

Epson LX300+

HP Desk Jet with serial interface

with parallel interface

6.2134.050 As above, but

6.2134.050 Character Set: HP Baud Rate: 9600 Data Bit: 8 Stop Bit: 1 Parity: none

RS232/ Parallel Converter

Baud Rate: 9600 Data Bit: 8 Stop Bit: 1 Parity: none Handshake: HWs

see Printer Manual

2 Installation

780/781 pH/Ion Meter, Manual

Settings

switched on. When the Vesuv program is started it automatically checks the configuration of the connected instrument and makes the corresponding settings for the report output so that data acquisition

2.3.6 Connecting a computer

The report output via the RS232 interface can be made to either a printer or a PC. With the program Metrodata Vesuv 3.0 for Windows it is possible to implement automatic data acquisition and evaluation.

This is done by connecting RS232 interface 10 of the pH/Ion Meter using the optionally available 6.2134.040 Cable (9-pin/9-pin) with a free serial COM port on the PC. If only a 25-pin COM port is available then the optionally available 6.2125.110 Cable (9-pin/25-pin) or a commercially available adapter must be used.

The RS232 interface must be configured with identical settings on both the connected instruments (PC and pH/Ion Meter). You should select the standard values for the pH/Ion Meter configuration under

FIG/RS232 settings

Baud Rate: 9600 Data Bit: 8 Stop Bit: 1 Parity: none Handshake: HWs

Please note that, before starting the program 'Vesuv Datalogger', the pH/Ion Meter must have been configured correctly, connected up and

CON-

(see Section 5.7):

functions properly.

As well as the data acquisition function described above, the 780/781 pH/Ion Meter also has numerous remote control possibilities that allow the complete control of the instrument via the RS232 interface. However, as the utilization of this option only makes sense in very special situations, you can obtain detailed information about the remote control language of the pH/Ion Meter from your local Metrohm agency in a separate document (780/781 pH/Ion Meter Operation via RS232;

8.781.1113).

2.4 Connecting the electrodes and sensors

780/781 pH/Ion Meter, Manual

switched off

Connection for potentiometric electrodes

Connection for separate reference electrode

Connection for temperature sensor

2.4 Connecting the electrodes and sensors

On its rear panel the 780/781 pH/Ion Meter has connections for a potentiometric electrode perature sensor

Connect your electrodes and sensors according to the following diagram to the

, a separate reference electrode 6 and a tem-

pH/Ion Meter:

Fig. 12: Connecting sensors

pH, ISE, redox or silver electrodes with built-in or separate reference electrode; plug F

plug B, 4 mm

Pt1000 or NTC, connected via two 2 mm banana plugs, reducing adapters for 4 mm plug B may be necessary (6.2103.130 / 6.2103.140). Please observe color classification for shielding purposes.

To help you choose the optimal potentiometric electrode for your particular application Metrohm can provide you with a range of information material:

Catalog: Metrosensor Electrodes

Product booklet: Electrodes for pH Measurement

Monograph 8.015.5003: Electrodes in Potentiometry

You can obtain these documents from your local Metrohm agency or under www.metrohm.com.

2 Installation

780/781 pH/Ion Meter, Manual

Mains cable

e sure that the power supply is always kept dry. Protect it

2.5 Mains connection

The pH/Ion Meter has an external power supply (6.2153.000) providing 12V (DC). This is connected to 12V mains connection

One of the following cables is supplied with the instrument

• 6.2154.000 Mains cable 2 Pol (C7) – EU (XVI)

• 6.2154.010 Mains cable 2 Pol (C7) – US (N1/15)

• 6.2154.020 Mains cable 2 Pol (C7) – GB (BS89/3)

• 6.2154.030 Mains cable 2 Pol (C7) – AUS (SAA/2)

and is connected to the external power supply.

Please mak against direct liquid contact .

2.6 Switch on

ON/ OFF

After the selected accessories have been connected switch on the pH/Ion Meter with the strument will start in the last operating mode to have been used for measuring pH, temperature, potential or concentration (781 only).

During the switch-on process an instrument checking routine is carried out automatically. If an error message is displayed here (' please contact your local Metrohm agency.

key (see also Section 4.3). The in-

Err x') then

2.7 Initial configuration

780/781 pH/Ion Meter, Manual

<CLEAR>

Dialog language: english

<ENTER>

Date and time

Temperature sensor and unit

2.7 Initial configuration

The pH/Ion Meter is delivered with standard settings for the configuration and method parameters. Many of these can be reset at any time by pressing the should ever be necessary to reset the configuration of the instrument to its original condition then this can be carried out by a re-initialization of the instrument memory (see Section 8.5).

Before you start to make measurements please check the following configuration settings and, if necessary, alter them according to your own requirements. If you first want to make yourself familiar with the operation of the pH/Ion Meter and the various editing possibilities then please read Sections 4.1, 4.2 and 4.4. More detailed explanations of the individual configuration settings are given in Section 5.

CONFIG/Verschiedenes/Dialog:english

key during input (see also Section 4.3). If it

After this choice has been confirmed with guage changes immediately. For example, this item would then appear.

CONFIG/auxiliaries/dialog:english

Please switch the instrument off and on if this setting has been changed.

CONFIG/auxiliaries/date

and /time

Please check that the date and time are correct.

CONFIG/auxiliaries/Temp.sensor and /Temp.unit

Enter the type of temperature sensor that is connected. If no temperature sensor is connected and you always want to enter the measuring temperature manually then you can ignore this setting.

the dialog lan-

3 Short operating tutorial

780/781 pH/Ion Meter, Manual

780 pH Meter (2.780.0010)

781 pH/Ion Meter (2.781.0010)

801 Magnetic Stirrer (2.801.0010)

pH electrode (enclosed)

Calibration buffers

3 Short operating tutorial

In this section the necessary steps for carrying out a simple pH and ion measurement with calibration are described. The instructions are limited to those steps that are absolutely necessary and will enable you to carry out your first measurements with the pH/Ion Meter directly. The operating principles are described in Section 4.4.

3.1 pH measurement

3.1.1 Requirements

The following instruments, accessories and solutions are required for carrying out the pH calibration and measurement described below:

•

Other stirrers can also be used (see Section 5.6).

•

Or another pH electrode with Pt1000 temperature sensor, e.g.:

6.0258.600 Unitrode, LL pH glass, with cable 6.2104.600, 2 mm temp. plug

6.0257.000 Aquatrode Plus for ion-deficient water, 4 mm temp. plug

6.0228.000 Solitrode, LL pH glass, PP shaft, 4 mm temp. plug

•

Metrohm buffer solutions pH 4.00, 7.00 and 9.00 (6.2307.230)

3.1.2 Preparations

Before you start this short tutorial you must ensure that the instrument and accessories have been correctly installed as described in Sec- tion 2. The most important points concerning the installation are briefly given again below (please refer to the Section mentioned for details). If you are not certain whether all the settings (

) correspond to the original conditions you can first reset any altera-

tions by initializing the memory ( tion 8.5).

The calibration parameters for the pH mode are set for a calibration using two Metrohm buffers as default (see Section 6.2.2). If you want to use other buffers then the corresponding buffer type must be entered.

1 pH/Ion Meter installation

CONFIG and PARAMETER

RAM Initialization) (see Sec-

• Set up instrument Section 2.1

• Connect stirrer Section 2.3.1

• Connect electrode Section 2.4

• Mains connection Section 2.5

3.1 pH measurement

780/781 pH/Ion Meter, Manual

pH 7

<CAL>

ENTER>

pH 4

<ENTER>

the measurement display. This can also be done immediately

<ENTER>

ON/ OFF

2 Initial configuration

CONFI G

3.1.3 pH calibration

1 Start calibration with first buffer

CAL

2 Continue calibration with second buffer

ENT ER

• Switch on pH/Ion Meter Section 5.4

• Set dialog language Section 5.4

• Set date/time Section 5.4

• Set temperature sensor Section 5.4

• Immerse pH electrode in buffer solution

• Switch on stirrer with

• Start calibration with

• If no temperature sensor is connected:

enter the temperature and exit with

• Remove pH electrode from first buffer, rinse with water and

blot off gently with a lint-free tissue

• Immerse pH electrode in second buffer solution

continue calibration sequence with

and

ENT ER

3 Result

• Wait for potential measurement, result will be displayed:

• After 30 s the pH/Ion Meter will switch back automatically to

with

3 Short operating tutorial

780/781 pH/Ion Meter, Manual

<ENTER>,

<MODE>

<CAL.DATA>

< -> >

<->>

<CAL.DATA>

b short); this contains

<->>

ENT ER

CAL. DA T A

REPORT

4 Poor calibration data

• If the calibration data are outside the calibration parameters

defined as the limits (see Section 6.2.2) then a corresponding message will be shown:

MODE

• You can still accept the calibration data with

ject it with

4 Show calibration data

• You can now display the calibration data with

If you move the selection bar to the end of the list with < then in the line

Curve

you can activate the calibration curve display with

4 Print calibration report

• With

printer or a PC.

• With

tion report in the report selection list (cali all the data except the calibration curve itself.

• The Select key

this also outputs the calibration curve.

you can now output a calibration report to a

you can jump directly to the short calibra-

offers the further option 'calib full';

or re-

>,

3.1 pH measurement

780/781 pH/Ion Meter, Manual

You can read off the actual pH of the sample from the display.

<MEAS/PRINT> you can start the output of a measuring

STI RRER

'mp

3.1.4 pH measurement

1 Select printout criterion

CONFI G

• If the obtained measured value is to be printed out directly as

a measuring point report or transferred to a PC then the required printout criterion must be set (see Section 5.2):

CONFIG/print meas.value/print crit.: drift

2 Start measurement

• Immerse the pH electrode in the sample.

• Switch on stirrer with

3 Determine measured value

•

It is stable when the drift display (small double arrow on the left-hand side) no longer blinks.

4 Print measurement

MEAS/

PRI NT

• With

point report on a printer or PC. The recording of the measurement and its output depend on the printout criterion 'Drift' and take place only when the current drift condition is fulfilled (see Section

781 pH/Ion Meter 01104 5.781.0020 date 2004-05-12 16:57:55 pH ******** run number 5 electr.id #5 pH = 5.875 20.2 °C Pt1000 ==============

6.2.1):

3 Short operating tutorial

780/781 pH/Ion Meter, Manual

781 pH/Ion Meter (2.781.0010)

801 Magnetic Stirrer (2.801.0010)

Fluoride ISE (6.0502.150) with cable (6.2104.020)

Ag/AgCl reference electrode (6.0726.100) with cable (6.2106.020)

Temperature sensor (e.g. Pt 1000, 6.1110.100) with cable (6.2104.140)

Fluoride standard solution (6.2301.030)

TISAB solution

TISAB

3.2 Determination of an ion concentration (only 781: Conc mode)

3.2.1 Requirements

Carrying out a calibration followed by the direct potentiometric determination of fluoride is described as an example. As this tutorial is only intended to provide a first introduction to ISE measurement with the 781 pH/Ion Meter, the automatic addition of the standard solutions is omitted in order to limit the number of accessories required. Further possible ways of carrying out a potentiometric fluoride determination, such as the automatic addition of the standard for calibration or standard addition, are described in Application Bulletin 82.

The following instruments, accessories and solutions are required:

•

Other stirrers can also be used (see Section

5.6

•

Electrolyte filling: inner and outer c(KCl) = 3 mol/L

•

c(NaF) = 0.1000 mol/L (1900 ppm F

•

NaCl, Na-acetate buffer pH 5.5; for preparation see below

3.2.2 Preparations

To prepare the dist. water and add 57 mL glacial acetic acid. Adjust the pH of the buffer with 5 M NaOH to 5.5. Then make up the solution to 1 L with dist. water.

Prepare the following five fluoride standard solutions from the stock solution: 0.5, 2.5, 5.0, 25.0 and 50.0 ppm. All standards should consist of a 1:1 mixture of dist. water and TISAB buffer.

Before you start this tutorial you must ensure that the instrument and accessories have been correctly installed as described in Section 2. The most important points concerning the installation are briefly given again below (please refer to the Section mentioned for details). If you are not certain whether all the settings ( correspond to the original conditions you can first reset any alterations by initializing the memory (

)

solution dissolve 58 g NaCl in approx. 500 mL

CONFIG and PARAMETER Conc)

RAM Initialization) (see Section 8.5).

3.2 Determination of an ion concentration (only 781: Conc mode)

780/781 pH/Ion Meter, Manual

<MODE>

<PARAM>

ppm

PARAMETER Conc

1 pH/Ion Meter installation

• Set up instrument Section 2.1

• Connect stirrer Section 2.3.1

• Connect electrodes Section 2.4

• Mains connection Section 2.5

2 Initial configuration

ON/ OFF

• Switch on pH/Ion Meter Section 5.4

• Set dialog language Section 5.4

• Set date/time Section 5.4

CONFI G

• Set temperature sensor Section 5.4

3.2.3 Calibrating the fluoride ISE

1 Set method parameters in the Conc mode

MODE

• Press

to enter the Conc mode

PARAM

• In the ion parameters (

with

> ion parameters

conc.unit: ppm

) set the concentration unit

• In the calibration parameters set the number of standards to

and define the concentrations:

> calibration parameters

no. of standards 5 addition: manual conc.1 0.5 ppm conc.2 2.5 ppm conc.3 5.0 ppm conc.4 25.0 ppm conc.5 50.0 ppm

3 Short operating tutorial

780/781 pH/Ion Meter, Manual

<CAL>

<ENTER>

2 Start calibration with first standard

CAL

• Immerse electrodes in the standard with the lowest F- concen-

tration

ENT ER

• Start calibration with

• If no temperature sensor is connected:

enter the temperature and exit with

• Confirm standard concentration with

or – if neces-

sary– correct it

• Wait for measurement of the potential

3 Continue calibration with increasing standard con-

centrations

• When the request 'Change std.

' appears, remove the electrodes from the first standard, rinse them with water and blot them gently with a clean lint-free tissue

• Immerse electrodes in the next standard and continue the cal-

ibration sequence with

• In each case conform the standard concentration with

or – if necessary – correct it

• Repeat procedure for each remaining standard

4 Result

• Wait for potential measurement, result will be displayed:

ENT ER

• After 30 s the pH/Ion Meter will switch back automatically to

the measurement display. This can also be done immediately with

3.2 Determination of an ion concentration (only 781: Conc mode)

780/781 pH/Ion Meter, Manual

responding message will

<ENTER>,

<MODE>

<CAL.DATA>

< -> >

<->>

<CAL.DATA>

tion report in the report selection list (calib short); this contains

<->>

CAL. DA T A

REPORT

5 Poor calibration data

• If the calibration data lies outside certain limits

(slope ≤ 80% or ≥ 105% of the theoretical slope of 59.16 mV (25°C) per ionic charge) or the sign of the slope does not agree with the selected ion type a cor be shown:

ENT ER

MODE

• You can still accept the calibration data with

ject it with

or re-

6 Show calibration data

• You can now display the calibration data with

If you move the selection bar to the end of the list with < then in the line

Curve

you can activate the calibration curve display with

7 Print calibration report

• With

printer or a PC.

• With

all the data except the calibration curve itself.

• The Select key

this also outputs the calibration curve (see Section 7.2.4).

you can now output a calibration report to a

you can jump directly to the short calibra-

offers the further option 'calib full';

>,

3 Short operating tutorial

780/781 pH/Ion Meter, Manual

'fc

781 pH/Ion Meter 01104 5.781.0010

date 2004-05-13 09:20:50

Conc ******** run number 1

electr.Id

conc.calibration

ion type F(-1)

temperature 22.7 °C

temp.sensor Pt1000

c.dat. 2004-05-12 09:32

conc/ppm U/mV dconc/%

std. 1 5.00E-01 139.9 0.2

std. 2 2.50E+00 97.0 0.1

std. 3 5.00E+00 78.8 -0.6

std. 4 2.50E+01 37.1 -0.2

std. 5 5.00E+01 19.2 0.4

variance 0.014

slope -59.9 mV

E(0) 120.8 mV

c(blank) 0.00E+00 ppm

==============

3.2 Determination of an ion concentration (only 781: Conc mode)

780/781 pH/Ion Meter, Manual

<PARAM>

can only be set when a Metrohm 8XX Stirrer is

<PARAM>

STI RRER

PARAMETER Conc

3.2.4 Direct measurement of fluoride

10 mL of the sample solution (e.g. 10 g table salt in 100 mL dist. water) is also treated with 10 mL TISAB solution. This should first be diluted 1:1 with dist. water. This produces the calculation parameters which are to be defined (see Section 6.5.4). As the measurement of the ions is carried out unstirred, the stirrer is only used before the measurement to ensure that the sample solution is properly mixed.

1 Set method parameters

PARAM

• In the Conc Mode define the stirrer control as a measuring pa-

rameter (

). Additionally the stirrer can also be

switched on and off manually before the measurement with

: > measuring parameters : :

stirrer: control

stirring rate 5

prestir pause 0 s stir time 15 s poststir pause 5 s

The stirring rate connected to the MSB interface.

• The calculation parameters (

: > calculation parameters : smpl.size 10.0 mL

V total 20.0 mL factor 1.0 smpl.size unit: mL

) are then:

2 Determine measured value directly

• Immerse electrodes in the sample.

• Switch on stirrer with

and – after sufficient time

has elapsed – off again.

• Wait until the electrodes have stabilized; i.e. until the drift sig-

nal in the display no longer blinks.

• Read off the value. This gives the fluoride concentration of the

sample solution without the addition of TISAB.

3 Short operating tutorial

780/781 pH/Ion Meter, Manual

'mp

3 Print out measured value

MEAS/ PRI NT

• With

you can start the measuring sequence (controlled stirring) and the output of a measuring point report on a printer or PC. The recording of the measurement and its output depend on the printout criterion 'Drift' and take place only when the current drift condition is fulfilled (see Sec- tion 6.2.1):

781 pH/Ion Meter 01104 5.781.0010 date 2004-05-13 09:45:24 Conc ******** run number 12 electr.id smpl.size 10.0 mL ion F(-1) #1 c = 25.7 ppm 23.6 °C Pt1000 ==============

3.2 Determination of an ion concentration (only 781: Conc mode)

780/781 pH/Ion Meter, Manual

4 Operation

780/781 pH/Ion Meter, Manual

4 Operation

4.1 The keypad

• Universal functions • Input of numbers and text

• Navigation

• Special functions

The keys beneath the display can be triggered from the measured value display irrespective of the mode.

Most of the keys on the right-hand side have two functions: The numbers to be entered and the navigation functions are shown in the center of the keys; the additional functions at their upper margin.

4.2 Operating concept

780/781 pH/Ion Meter, Manual

measured value display.

menu display

measured value display

<ENTER>

<MODE>

menu display with <CONFIG>

<PARAM>

4.2 Operating concept

The pH/Ion Meter provides two types of display:

The

This is the normal instrument display.

This is used for editing various settings.

In the directly measuring working modes the current measured value is shown together with the date and time in the the Conc mode the method name and the type of ion selected are also shown. If the result is to be printed out, or if a stirring sequence or the entry of sample identifications (Id) are intended for recording a measured value, then this is started with with standard or sample addition or subtraction the last result to be determined is always shown. In this case a measuring sequence is started with ing mode of the pH/Ion Meter is changed with easily see which mode is set from the measuring unit or the prefix 'pH' shown in the display.

In each operating mode you can switch from the measured value display to the the instrument configuration and the method parameters to be edited. In the direct measuring modes measurement recording and evaluation (e.g. automatic printing and limit monitoring) continues in the background. In the menu display it is also possible to change directly from the configuration to parameter input with with

. The measured value display changes when the operat-

. In the Conc mode

. You can

. This allows

and vice versa

. In

4 Operation

780/781 pH/Ion Meter, Manual

ON/ OFF

CONFI G

PARAM

<PARAM>

<PARAM>

CAL

<CAL>

MEAS/

PRI NT

• Depending on the configuration (see

4.3 All key functions at a glance

The functions of all the keys are described below both for the measured value display and the menu display:

Key Measured value display

(normal operation)

On/Off switch

• The

instrument on and off

• This applies even if the lamp of the

LCD display is switched off! (see Section 5.4)

• After switch-on the pH/Ion Meter is in

the normal operation display of the last mode to have been used

key switches the

Opens configuration menu

•

for the instrument configuration.

• These configuration settings remain

unchanged until they are edited or the permanent memory of the instrument configuration is initialized (see Sec- tion 8.5).

opens the selection menu

Report selection

• Direct selection of the configuration

report after

Menu display

(editing)

On/Off switch

• The

instrument off at any time.

key switches the

Changes to configuration

• The

switch directly from the parameter menu to the selection menu for instrument configuration.

key can be used to

Opens parameter menu

• The

tion menu for the method parameters.

• All parameter settings belong to a

method and are stored methodspecifically with this method.

key opens the selec-

Report selection

• Direct selection of the configuration

report after

Starts calibration

• In the pH and Conc (direct) modes the

key starts a calibration.

Starts measurement / Prints out measured value

• In the pH, T, U and Conc(direct)

modes the gers a measuring sequence.

key trig-

Changes to parameter menu

• With the

switch directly from the configuration menu to the parameter menu.

key you can

4.3 All key functions at a glance

780/781 pH/Ion Meter, Manual

MODE

<MODE>

QUI T

<QUIT>

CAL. DA T A

<CAL.DATA>

USER

<USER>

REPORT

<CAL.DATA>

ADD. DA T A

<ADD.DATA>

Key Measured value display

(normal operation)

Section 5.2), the prints out the measured value as a measuring point report.

Operating mode selection

• In the pH, T and U modes (780 pH

Meter) and the pH, T, U and Conc modes (781 pH/Ion Meter) the

key changes the mode.

Message acknowledgement

• Displayed messages are normally

acknowledged with tions: see Section 8.2)

• If cause of the message has not been

remedied then it will appear again at the next check.

Displays calibration data

• In the pH and Conc(direct) modes the

calibration data.

key shows the current

key

. (Excep-

Menu display (editing)

Cancels sequence

• With the

quences are terminated without direct transfer of the data.

key working se-

Cancels working step

• Queries are exited with

this way it possible, e.g. to skip individual steps within a working sequence without accepting the data.

• In menus

the next higher level.

causes a jump to

Enters the number '7'

. In

Report selection

• Direct selection of the configuration

report after

User selection

• With

newly entered, selected or deleted.

a user name can be

Report selection and printout

• With

selected and printed out.

• The selection of the report from those

available is made either with

corresponding key (e.g.

Report selection).

a report can be

or directly by pressing the

, see right-hand column:

Shows addition data

(781 pH/Ion Meter only)

• In the Conc Mode

shows the data of the last measurement for standard and sample addition methods.

Enters the number '8'

Enters the number '9'

Enters the number '4'

Report selection (781 pH/Ion Meter only)

4 Operation

780/781 pH/Ion Meter, Manual

•

ST ORE

<STORE>

RECA L L

EL. TEST

<EL.TEST>

STI RRER

M ET HODS

Key Measured value display

(normal operation)

Direct selection of the short result

report after

Stores measured value

• In the pH, T, U and Conc(direct)

modes the measuring sequence and stores the measured values in the memory in a similar manner to

• The storage criterion must have been

previously defined under CONFIG /Store meas. value.

key triggers a

Opens measured value memory

• The measured value memory is

opened with the stored measured values can then be viewed or deleted.

Report selection

• Direct selection of the measured value

memory report after

Menu display

(editing)

Enters the number '5'

Enters the number '6'

key. The

Starts electrode test

• In the pH mode you can start an elec-

trode test with the

key.

Report selection

• Direct selection of the pH electrode

test report after

Stirrer on/off

• A connected stirrer can be switched

on and off manually with the

key.

Method selection

• With the

tion for loading, saving or deleting a method is opened (see Section 6.1).

key the selec-

Report selection

• Direct selection of the method memory

report after

Enters the number '1'

Enters the number '2'

Enters the number '3'

Enters the number '0'

4.3 All key functions at a glance

780/781 pH/Ion Meter, Manual

ABC

<.>

<ABC>

/exp>

<-/exp>

SEL ECT

<ENTER>

Key Measured value display

(normal operation)

-/ exp

and

Menu display (editing)

Enters a decimal point '.'

• The

the input field.

key enters a decimal point in

Exception: open text editor

• If the

input field where text input is possible then a text input box for editing the text will be opened.

key is first pressed in an

Enters a minus sign '-'

• If you start a numerical input with

then the numerical value to be

entered will receive a minus sign.

Enters an exponent 'E'

• When a numerical input has been

started then the vide an exponential notation.

key will pro-

Selects predefined entries

• For menu parameters which offer a

fixed choice of settings (recognizable by the final colon) the selection list can be viewed with the The arrows determine the selection direction.

- keys.

Cursor control for text input

• In the text editor the arrow keys are

used to select the character to be entered and the it.

key to enter

4 Operation

780/781 pH/Ion Meter, Manual

CONTRAST+

CONTRAST -

<CONTRAST+>

<CONTRAST->

<>

<>

<ENTER>

<>

CLEAR

<CLEAR>

ENT ER

<ENTER>

and

Alters display contrast

• The contrast of the LCD display can

be altered with the and measured values display.

• This setting is retained after the in-

strument has been switched off and on. The default value is only reset after the memory has been initialized.

keys during the

Controls the menu bar

• In each menu display the

keys can be used to move the

selection bar up and down by one line.

Cursor control for text input

• In the text editor the arrow keys are

used to select the character to be entered and the it.

Leafing between entries in

the measured values memory

• Leafs between the entries in the

measured values memory display: starting from the last measured value to be stored you can access older entries with

• At the beginning and end of the list

you can use the corresponding arrow key to jump directly to the other end of the list.

and vice versa.

and

key to enter

Deletes text input

• Before opening the text editor during

text input the the complete entry. Within this box

deletes the character to the

left of the cursor.

key will delete

Shows special value

• If a special value exists for an entry or

selection then this can be shown with the

key.

Shows standard value

• All other entry and selection possibili-

ties provide the standard value with the

key.

Confirms entry

• The

plete each entry with the selection bar moving on to the next parameter. If an entry is exited without this confirmation then the entered value will be rejected.

key is used to com-

4.4 Operating principles

780/781 pH/Ion Meter, Manual

PARAMETERS

<PARAM>

<>

<>

<ENTER>

<QUIT>

<ENTER>

<QUIT>

<ENTER>

Entries with a fixed selection

<ENTER>

<CLEAR>

Entries which can be edited

<ENTER>

Numbers

<-/exp>

SEL ECT

4.4 Operating principles

4.4.1 Configuration and method parameters

Instrument configuration and method parameters are each contained in menus with a tree structure. These menu structures are shown in the Annex in Section 9.3.

The instrument configuration of the pH/Ion Meter is described in the CONFIG menu. This contains the basic settings that apply for all the selected working modes and methods. The method parameters are stored under od parameters depend on the measuring mode which has been set.

The change from the measured value display to the menu display is made by using the submenu appears first, and is shown with an '>' (e.g. >Measuring parameters). You can now move the selection bar up and down with

and

the

arrow keys. Each underlying level in the menu structure is opened with tions to individual entries must be confirmed with terations are exited with

. In contrast to the configuration, the meth-

and exited with

then they remain ineffective.

keys. The title of the

. If such al-

. Altera-

If an entry is confirmed with to the next entry. At the end of a submenu it will finally change to the next point of the superior menu selection.

In this way you can run through the complete menu structure for the configuration and parameters by repeatedly pressing the key. This can be helpful when carrying out checks.

Not all parts of the menu structure described below are visible in the display at all times. Only the specific possible settings of the option which is currently activated are shown. For example, the various settings for printing out the measured values under

values/print crit.

tivated completely (OFF). If one of the other printing criteria is selected then the particular settings it requires will appear in the display.

4.4.2 Editing menu entries

A basic differentiation is made between two types of menu entry.

dialog: english, deutsch, français, español

The selection is then made with the with print, can be shown by pressing

then the selection bar will move

CONFIG/print meas.

are not visible when printing has been deac-

are indicated by a colon:

keys and confirmed

. The default setting, which is normally shown in bold

ENT ER

confirming it with

are entered directly with the number keys. Exponential notation can be activated directly with the

are altered by entering a new value and

key.

4 Operation

780/781 pH/Ion Meter, Manual

<QUIT>

<CLEAR>

<ENTER>

Text entries

<ABC>

<CLEAR>

<EN-

TER>

<CLEAR>

<QUIT>

<ENTER>

<QUIT>

ABC

Values outside the valid range of limits for the particular entry will not be accepted by the instrument. This is indicated by the invalid entry blinking. You can now either enter a new value or retain the original value by exiting with

Special entries exist for some numerical entries; these cannot be seen directly and cannot be edited (e.g. 'OFF' for the measuring parameter Drift). These can be shown with

and confirmed with

4.4.3 Entering text

You can use the input of alphanumeric characters:

This text editor must be called up right at the start of a new entry after the old entry has been completely deleted with sary. If a text input is started directly with numbers from the number block of the keyboard then the subsequent opening of the text editor is no longer possible.

The required characters are selected with the arrow keys. The cursor movement can be accelerated by keeping the arrow keys pressed down. The marked character is accepted in the input field with

that there free places are available. Otherwise you can delete individual characters from the back with

are made using the text editor and are described in the following section.

. A requirement is that a blinking cursor in the input field indicates

to open a text editor for entering texts; this allows

, if neces-

Text input is terminated by exiting the text editor with firming the entry with jected then

must be activated a second time.

. However, if the whole entry is to be re-

and con-

4.4 Operating principles

780/781 pH/Ion Meter, Manual

5 Configuration

780/781 pH/Ion Meter, Manual

<CLEAR>

5 Configuration

CONFI G

With the contains all the instrument settings for the pH/Ion Meter. These are independent of both the mode and the method. This means that they cannot be stored separately like the method parameters (see Sec-

tion

memory containing the instrument configuration is re-initialized (see Section 8.5).

All the settings of this menu are described in this section. English is used as the dialog language. For each point you will find all the possible entries or the valid entry range together with the default value. This will always be reset when the permanent memory of the pH/Ion Meter is re-initialized. During the input you can also deliberately call up the default value with

Example:

time interval 1,2,3...365...9999 d

This setting defines a time interval in days. In this example it is the time after which the validation of the instrument is to be carried out (

toring/validation

and 9999 or call up the default value of 365 days with

6). They continue to exist until they are edited or the permanent

key you can access the configuration menu. This

. It is shown in bold type below.

). You can either enter whole numbers between 1

>moni-

5.1 Report

780/781 pH/Ion Meter, Manual

REPORT

└

Report Id:

'mp

Instrument Id:

781 pH/Ion Meter 5.781.0020

Date, Time:

Datum 2004-05-24 09:50:56

User *:

user C. Weber

Mode / Method / Run number:

pH pH-1 run number 9

Electrode Id:

electr.id pH electr.1

Sample Id1:

id1 batch 21

Sample Id2:

id2 sample A01

Signature:

Signature ________________________

<USER>

5.1 Report

CONFIG

├ report

│ ├ id1 : ├ id2 ├ report id ├ instrument id ├ date & time ├ method ├ electrode id ├ signature

In the configuration menu report you can define the output format of the report header. This describes the first lines of a measuring point report (see also Section 7.2.3) and can be either placed in front of each measured value to be printed out or before a series of measured values (see following section).

A report header containing all the elements described here could look

like this:

line feed

*The 'user' line is not configured here. The entry of a user name takes place automatically when a user has been defined with the key. The name remains active until it is deleted or another user name is selected (see Section

id1, id2 (max. 16 characters)

This is where you can define short texts as additional information for the report header. Each of these entries will be printed out in a single line in each report. In addition, you can also request these Ids before each measurement as a preselection (see method parameter

tions

report id: ON, OFF

This setting defines whether the report Id is to be printed out in the first line of the report header. It is used to identify the report.

instrument id: ON, OFF

You can include the instrument identification in the report header if you want to. It consists of the exact type name of the pH/Ion Meter with the version number of the instrument software.

in Section 6), e.g. in order to mark each sample specifically.

4.3).

preselec-

5 Configuration

780/781 pH/Ion Meter, Manual

<CLEAR>

An additional way of assigning report printouts to a particular instrument is by using an individual instrument name under

FIG/auxiliaries/device label

(see Section 5.4). This will then be

CON-

printed out automatically in a separate line in the report header after the instrument Id.

date & time: ON, OFF

This setting defines whether the date and time of the report printout are to be printed. The date and the exact time of the measurement can additionally be printed with each successive measured value (see following section).

method: ON, OFF

As well as the mode name, the name of the method used can also be printed out in the report header if required. You can define this previously by storing the method parameters used with

. If no

method name has yet been defined then the character sequence

******** will appear.

electrode id: ON, OFF

You can include the electrode name in the report header if you have defined an electrode ID for the currently valid calibration. Otherwise this field in the report header will remain empty.

signature: ON, OFF

Reports which contain measuring data (measuring point, addition, calibration and electrode test reports) can, depending on the configuration, have a signature line added on. In this way the result can be provided with a signature.

line feed form, 0,1,2,3...999

The paper feed of the printer at the end of a report can be set here. With continuous paper printers (e.g. Custom) you can select the number of empty lines so that after the report has been printed out you can tear off the printed paper directly at a suitable point. For single page printers (e.g. HP DeskJet) you can enter the special value '

so that the printed page will automatically be produced by

form' with

the printer after each report.

5.2 Printing out measured values

780/781 pH/Ion Meter, Manual

MEAS/

PRI NT

└

<MEAS/PRINT>,

immediate-

time

drift

plot

5.2 Printing out measured values

CONFIG

├ print meas.value : └ print crit ┬ immediate ┬ date & time │ ├ report header │ └ calibration report ├ time ┬ date & time │ ├ report header │ ├ calibration report │ ├ time interval │ └ stop time ├ drift ┬ date & time │ ├ report header │ └ calibration report ├ plot ┬ time interval │ ├ time scale │ ├ time scale label │ └ stop time

OFF

In the configuration menu print meas.values the output form of measured values, triggered by possible for the direct measuring modes pH, T, U and Conc(direct).

print crit: immediate, time, drift, plot, OFF

Depending upon the print criterion a measured value report with be transmitted via the RS232 interface to a printer or PC either

, at defined

filled. If a stirring sequence is intended before the measurement (

RAMETERS/measuring parameters/stirrer: control,

6), then these print criteria will only be effective when the stirring

tion

sequence has been concluded.

A further way of documenting the measured values is to output a graphical

print crit.: immediate

With this setting a measured value report will be produced when

following options can be used:

date & time: ON, OFF

intervals or only when a

of the measure value signals.

is activated from the normal instrument display. The

is defined. This is only

condition has been ful-

PA-

see Sec-

Here you can choose whether the date and time at which the measured value was recorded are to be included with each individual measured value. This can take place irrespective of whether a report header is used.

report header: once, always, OFF

5 Configuration

780/781 pH/Ion Meter, Manual

<QUIT>

Normally each measured value is accompanied by the report header for documentation purposes. The exact contents of the report header are defined under CONFIG/Report (see above).

With a larger series of manually triggered measurements it may be advisable to print out the report header only once with the first measured value. In this case all the measurements should be made under the same conditions. The report header will only appear again when the run number has been reset to zero by switching the instrument off and on.

calibration report: ON, OFF

You have the possibility of providing each measured value with the associated calibration data of the electrode used, e.g. within the context of a GLP documentation.

print crit: time

With this print criterion you can automatically record and output the measured values at fixed intervals. The following options are used:

date & time: ON, OFF report header: once, always, OFF calibration report: ON, OFF

These settings correspond to those of the print criterion 'immediate' (see above).

time interval: 0.1...4.0...99999.0 s

Automatic measuring value recording can be carried out at time intervals of down to 0.1 s. Please note that if small time intervals are used then the amount of data for each measured value must be adapted accordingly, as otherwise the buffer memory of the connected printer or PC would be filled too quickly. This means, for example, that the report header should only be printed out once at the start of a series of measurements. Otherwise data could be lost at the RS232 interface of the receiver. In this case you should consider matching the measured value recording interval to the measured value memory (see Section 5.3).

stop time: OFF, 1...999999 s

The time after which an automatic series of measurements is to be terminated can be entered in whole seconds. You can also let a series of measurements run indefinitely without a fixed stop time and then stop it manually with

if you select 'OFF' for this

setting.

5.2 Printing out measured values

780/781 pH/Ion Meter, Manual

<QUIT>

print crit.: drift

If this print criterion is used then a measured value will only be documented when the drift condition defined under

ing parameters/drift

has been fulfilled.

PARAMETERS/measur-

date & time: ON, OFF report header: once, always, OFF calibration report: ON, OFF

These settings correspond to those of the print criterion

immediate' (see above).

print crit.: plot

The directly recorded values can be outputted graphically as a measured value/ time plot.

time interval: 0.1...4...99999.0 s

In a similar way to the print criterion 'time' a time interval can be defined for graphical measured value recording.

time scale: 5,10,30,60,120,180..99960

This is the time axis scale. The reciprocal value of the quantity entered corresponds to the paper feed rate. This means that, e.g., for a required feed rate of 2 cm/min a time scale of ½ min/cm = 30 s/cm must be entered.

time scale label.: rel, abs

The time axis scale can use the relative time in minutes and seconds (start = 0 s). The current time can also be used with '

stop time: OFF, 1...999999 s

The graphical plot is terminated when the stop time has elapsed or will continue indefinitely (' possible with

OFF'). In both cases termination is

s/cm

abs'.

5 Configuration

780/781 pH/Ion Meter, Manual

ST ORE

└ stop time

<STORE>

5.3 Storing measured values

CONFIG

├ store meas. value : └ store crit ┬ immediate, drift, OFF └ time ┬ time interval

In the direct measuring modes pH, T, U and Conc(direct) you can use

mation in the instrument memory (see Section settings to be defined under to those made under

store crit: immediate, time, drift, OFF

This storage criterion also only becomes effective when an optional stirring sequence has been concluded.

In contrast to the report output, the combination of the information stored together with each measured value is fixed.

to store up to 100 measured values with additional infor-

CONFIG/store meas. value correspond

CONFIG/print meas. value:

7.3). The functions of the

store crit: immediate

The current measured value is stored with

store crit: time

time interval: 0.1...4.0...99999.0 s stop time: OFF, 1...999999 s

You can automatically record and save the measured values at fixed time intervals until the stop time has been reached.

store crit: drift

A measured value can also be stored when the drift condition defined under

After 100 measured values have been stored, and each time a further storage attempt is made, the pH/Ion Meter will produce a corresponding warning:

You now have the possibility of using measured values, of deleting individual measured values or of clearing the whole measured value memory (see Section to output all measured values as a report via the RS232 interface (see Section 7.2.8).

PARAMETERS/measuring parameters/drift has been fulfilled.

measured value memory full

7.3). It is also possible

to view the stored

5.4 Auxiliaries

780/781 pH/Ion Meter, Manual

└ program

5.4 Auxiliaries

CONFIG

├ auxiliaries

: ├ run number ├ last digit ├ dialog ├ display ├ LCD off after ├ date ├ time ├ time zone ├ temp.sensor ├ temp.unit ├ device label ├ beep

Various basic settings for the configuration of the pH/Ion Meter are made in this submenu.

run number 0,1,2,3...999, OFF

The run number is included in the report. It is increased by one after each measuring process. This applies to both the storage of measured values and to the calibration or pH electrode test and makes the later chronological assignment of such different measuring processes easier.

When the instrument is switched on the run number is automatically set to '0'. The first measuring process begins with '1'.

last digit: ON, OFF

This setting can be used to conceal the last decimal place of the measured value display. The displayed value is rounded off accordingly. This can be useful in improving the readability of a rapidly changing measured value. Please note that this setting does not influence the drift control of a measurement.

dialog: english, deutsch, français, español

The dialog language covers both the language shown on the display and that used in the report. Switch the instrument off and on if this setting has been changed.

display: positiv, negativ

You can choose whether you want to have a positive or negative display presentation, e.g. in order to adapt it to the local lighting conditions.

5 Configuration

780/781 pH/Ion Meter, Manual

<QUIT>

LCD off after 1,2...999 min, OFF

The display of the pH/Ion Meter has an illuminated background. In order to increase the working life of the lamp you can switch off the display automatically when the instrument has not been used for a certain time. Please note that, if the lamp is switched off and on too frequently then its working life will also be reduced. This means that times of about 30 min can be recommended.

The fact that the LCD illumination is switched off does not affect the functioning of the pH/Ion Meter in any way. It continues to work normally. The lamp can be activated again with any key except Please note that the

key switches the instrument off. All other keys only have the function of activating the LCD illumination. This means, for example, that runs will not be terminated when the key is used to reactivate the background illumination.

date YYYY-MM-DD time hh:mm:ss

You can set the date and time here. The program will only accept numbers which make sense.

time zone 12 ASCII characters

For complete documentation you can add details of the time zone to the time information for output in the report header. The input of up to any 12 characters is possible. Examples: 'MEZ', 'UTC-05:00' (Coordinated Universal Time minus 5 h) or location of the measurement.

temp.sensor: Pt1000, NTC

The 780/781 pH/Ion Meter supports the use of two different types of temperature measuring techniques T: Pt1000 (platinum resistance thermometer) and NTC ('Negative Temperature Coefficient' semiconductor). This means that the configuration must be adapted accordingly. If NTC sensors are used then it is also necessary to enter two sensor characteristics; these can be found in the specification of the sensor:

R(25 °C) 10000...30000...100000 B value 1000...4100...9999

The standard values R(25 °C) = 30000 ohm and B value = 4100 K apply to the use of a Metrohm electrode with NTC sensor (e.g. 6.0228.010 LL Solitrode NTC), where the B value refers to 25 °C and 50 °C. B values of other NTC sensors are frequently based on different reference temperatures (usually 25 °C / 50 °C – 100 °C). When entering your own sensor characteristics the effect of the second reference temperature on the measuring accuracy of an NTC sensor is negligible.

5.4 Auxiliaries

780/781 pH/Ion Meter, Manual

temp.unit: C, F

The pH/Ion Meter can work with temperature information in both °C and °F units.

Please note that, when changing this setting, the default value of the measuring parameter drift in the T mode has the unit °C and, if necessary, must be converted as follows:

TF = 32 + 1.8 ·TC or TC = (TF – 32)/1.8

TF: temperature in °F

: temperature in °C

device label 12 ASCII characters

If apart from the instrument Id you wish to assign a further name to a particular pH/Ion Meter for inclusion in the report then you can enter your text here, e.g. '

Lab 2.01' or 'Works 2'. This will then be included in

the report header in a separate line inserted after the instrument Id.

beep: OFF,1,2,3

Messages on the display of the pH/Ion Meter are accompanied by a beep. This can be switched off completely or just limited to a sequence of 2 or 3 beeps.

program

This is the version number of the instrument software and cannot be altered. It is included in the report header as part of the instrument Id.

5 Configuration

780/781 pH/Ion Meter, Manual

└ system test report

<CLEAR>

<CON-

FIG>

SETUP

5.5 Monitoring

CONFIG

├ monitoring

: ├ validation ├ service

The 780/781 pH/Ion Meter can inform you automatically about reoccurring quality monitoring tasks.

validation: ON, OFF

If this option is active then you can enter a time interval in days and, when it has elapsed, the instrument will request you to carry out a validation process.

In addition, the time counter shows the elapsed time in days since the last time that this option was switched on. When the time counter reaches the set number of days then the following message will appear:

time interval 1...365...9999 d time counter 0 d

validate instrument

This will also be included in the report header. It can only be removed in the following ways:

• Resetting the time counter to zero under

validation

• Extending the time interval and then switching the instrument off

and on again

• Switching off the validation monitoring option

In order to prevent unauthorized removal of the message the

key can be disabled under the instrument

7.5.1), so that the settings described above are no longer accessi-

tion

ble.

service: ON, OFF

next service YYYY-MM-DD

At a particular time the instrument can remind you about the date when a service is due. When the set date has been reached the following message appears on the display:

with

service is due

CONFIG/monitoring/

(see Sec-

This is also included in the report header and can be switched off by either entering a new and later service date or by switching this monitoring function off.

5.6 Peripheral units

780/781 pH/Ion Meter, Manual

└

system test report: ON, OFF

When it is switched on the 780/781 pH/Ion Meter automatically carries out a system diagnosis. The result can be outputted as a system test report (see Section 8.4.1).

5.6 Peripheral units

CONFIG

├ peripheral units

: ├ character set ├ Dosimat ├ stirrer ├ keyboard

barcode

Various peripheral units can be connected to the 780/781 pH/Ion Meter. The corresponding configurations must be carried out here.

character set: IBM, Epson, Seiko, Citizen, HP

The type of printer chosen for the report printout is selected here. If you have connected a PC to the RS 232 interface for data reception then set this parameter to '

IBM'.

Dosimat: 665, 725, 765, 776

The 781 pH/Ion Meter can be used to control a Metrohm Dosimat Plus, e.g. for the automated production of standard solutions for the calibration of ion-sensitive electrodes. Analyses involving the addition of standard and sample solutions can also be automated in this way. In order to control an 865 or 876 Dosimat Plus, make sure that the Dosimat 665 is selected. Please note the required settings at the Dosimat Plus (see Ch. 2.3.3).

stirrer: 8xx, 7xx

Metrohm stirrers of the series 8xx and 7xx can be connected to the pH/Ion Meter. In order to connect 7xx series stirrers the use of a remote box (6.2148.010) at the MSB connection of the pH/Ion Meter is necessary (see Section 9.5 switched on and off from the pH/Ion Meter with

). For example, both types of stirrer can be

. With 8xx series stirrers the stirring rate can also be controlled from the pH/Ion Meter (see are using a stirrer of another manufacturer, then you must select

PARAMETERS/measuring parameters/Stirrer). If you

'7xx'.

keyboard: US, deutsch, français, español, schweiz.

If texts have to be entered frequently it may be a good idea to connect a PC keyboard. The language-specific keyboard layout is then set here. Older PC keyboards may possibly have a too-high power consumption, which could result in the cancellation of the system test when the in-

5 Configuration

780/781 pH/Ion Meter, Manual

strument is switched on. In such a case remove the connected keyboard and switch on the instrument again.

5.7 RS232 settings

780/781 pH/Ion Meter, Manual

└

barcode: input, id1, id2

For data input you can also use a barcode reader which provides a PS/2 connection. Older barcode reader may possibly have a too-high power consumption, which could result in the cancellation of the system test when the instrument is switched on. In such a case remove the connected keyboard and switch on the instrument again.

5.7 RS232 settings

CONFIG

└ RS232 settings ├ baud rate ├ data bit ├ stop bit ├ parity

handshake

For communication with instruments (printer, PC) connected to the serial RS232 interface the correct setting of these parameters is required:

baud rate: 38400, 19200, 9600, 4800, 2400, 1200, 600, 300 data bit: 7, 8 stop bit: 1, 2 parity: even, none, odd handshake: HWs, SWChar, SWline, none

Please refer to the manual of your printer for the exact settings. When a computer is connected the corresponding configuration can usually be carried out in the terminal program used.

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

└ delete method

<ABC>

M ET HODS

6 Methods / Parameters

The exact measuring method of the pH/Ion Meter is described by method parameters which, like the instrument configuration, are arranged in a tree structure in the menu display. The complete tree is shown in the Annex (see Section 9.3) to provide a better overview.

The parameters are set in a similar way to the instrument configuration. In contrast, however, the administration of the method parameters is mode-specific. The selection of the method parameters also varies with the selected mode. For this reason the method parameters for each mode are described separately in this section.

This means that one of the following subsections, together with the instrument configuration, forms a complete description of all the settings which are important for the operation of the pH/Ion Meter in a particular measuring mode.

Please note that editing numerical values with more than 7 digits can result in rounding effects. In this case, consider the exponential notation or a different concentration unit (see Section 6.5.2, 781 only).

6.1 Method management

Press

as a method. You can also load or delete methods within this dialog.

METHODS

├ recall method ├ store method

For each selection you can edit a method name with one with

All saved methods are accessible in all modes. If you load a method which requires a different mode than the actual, the pH/Ion Meter will switch to this mode automatically.

if you want to save all current parameter settings

or select

6.2 pH measurement (pH mode)

780/781 pH/Ion Meter, Manual

└

measuring parameters

<CAL.DATA>

6.2 pH measurement (pH mode)

6.2.1 Measuring parameters

PARAMETER pH

├ measuring parameters

: ├ electr.id ├ drift pH ├ temperature* ├ method ├ delta measurement

stirrer

(* only appears if no temperature sensor is connected)

The importance for the measurement.

electr.id: 12 ASCII characters

You can assign any name you like to the connected pH electrode. During a calibration the resulting calibration data will be assigned to this entered electrode Id and stored. The electrode Id will then be included in the report header for the output of measured values.

describe the settings which are of direct

In this way you can enter several electrode Ids. This allows you to switch between various pH electrodes with their associated calibration data. However, a requirement is that each new electrode Id is linked with a new calibration. Then you can use uring parameter

In order to delete an electrode Id and its linked calibration data this must be reset under

drift pH 0.001...0.050...9.999/min, OFF

A measuring signal which changes as a function of time is regarded as being sufficiently constant when its drift drops below the value defined here. This can be used as criterion for the pH/Ion Meter if a displayed measured value is to be stored or documented by printing a report (see print criterion and storage criterion in Section 5.2 and Section 5.3). Please note that for a drift-controlled measured value recording this drift parameter must not be set to ' ported.

If the drift condition is not fulfilled then this is indicated by two constantly blinking triangles in the display.

An active drift control increases the reproducibility of the measurements as a constant condition is used to define the measured result. A smaller value for the measuring parameter Drift pH requires a more stable measuring signal than a larger one. The set measuring parameter is also proportional to the measuring uncertainty of the measured value obtained.

Electr.Id to select one of the stored electrode Ids.

(Reset cal., see Section 7.1.1).

OFF', as otherwise no result will be ex-

under the meas-

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

Please note that the drift condition defined here and the temperature parameter described below do not apply to the calibration and, if necessary, must be set separately under the calibration parameters.

temperature -999.9...25.0...999.9 °C

This menu item only appears when no temperature sensor is connected. In this case you can enter the temperature of the sample solution here. If the measuring and calibration temperatures are different then it is necessary to record the temperature for the automatic correction of the electrode slope (temperature compensation, see Section 9.2.1). Information about the measuring temperature is also absolutely necessary for the complete documentation of a pH value. In the report printout of the measured value this manually determined temperature is indicated by the suffix '

manual'.

method 8 ASCII characters

All parameter settings can be stored together or loaded as a method (see Section 6.1). The name of the current method is then given here. This field is only used for information here and cannot be edited directly.

delta measurement ON, OFF

The delta measurement permits the display of the measured value relative to a freely selectable constant reference value:

reference pH -19.999...0.000...19.999

This reference value is subtracted from the measured value itself. The modified measured value is shown together with this value and is taken into consideration, for example, in checking the limit values (see

RAMETER pH/limits pH

). The reference value is not included in the

PA-

report. However, should you still want to document it then you should also produce a parameter report (see Section 7.2.7).

stirrer: ON, OFF, control

You can choose whether the pH measurement is to be made while stirring is being carried out or not. A requirement is that a Metrohm stirrer is connected with a suitable cable (see Section 2.3). If an 8xx series stir- rer has been connected and the settings made under

FIG/peripheral units

then the stirring rate can also be selected:

CON-

stirring rate 1...5...15

If you want your measurement to be made without stirring but still want to stir the solution before the measurement then you should select the

control setting. In this way you can trigger a stirring sequence before

the start of each measurement with

prestir pause 0...99999 s stir time 0...99999 s poststir pause 0...99999 s

6.2 pH measurement (pH mode)

780/781 pH/Ion Meter, Manual

MEAS /PRINT

drift-controlled

PARAMETER pH

└ offset Uoff state

The prestir and poststir pauses represent waiting periods in which stirring does not take place. The measurement itself only starts when the complete stirring sequence has ended.

Please note that this parameter is binding for the report output and for storing a measured value. Therefore when you start a measurement with < ly. This is why you should preferably carry out ments (see Section

> the stirrer will be switched on and off according-

measure-

5.2 and Section 5.3).

6.2.2 Calibration parameters

├ calibration parameters

: ├ temperature* ├ drift ├ report ├ cal. interval ├ no.of buffers ├ buffer type ├ low lim.slope ├ up lim.slope ├ low lim.pH(0) ├ up lim.pH(0)

(*only appears if no temperature sensor is connected)

The calibration parameters describe the most important settings for the calibration such as buffer types and tolerance values. The evaluation of the pH calibration is described in Section 9.2.1.

temperature 0.0...25.0...99.9 °C

Just as for the measuring temperature, the calibration temperature should also be entered when no temperature sensor is connected. If the measuring and calibration temperatures are different then this is absolutely necessary for the automatic temperature correction of the electrode slope. The temperature is also stored with the suffix '

' and marked in this way in the calibration report.

manu-

The exact temperature recording is also important for the pH calibration as the pH/Ion Meter works with automatic buffer recognition (see below:

buffer type).

drift 0.1...0.5...9.9 mV/min

Just as in the pH measurement, the potential measurement for the pH calibration is drift-controlled. However, this drift control cannot be switched off. Please note that, in contrast to pH measurement, the drift for the pH calibration is entered in mV/min. It is therefore inevitably different from the drift for pH measurement (see Section 6.2.1).

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

<MODE>

<QUIT>

<ENTER>

report: OFF, short, full

After the calibration it is possible to output the calibration data automatically in the form of a report. You should chose between the 'short' version which contains all the relevant data and the 'full' version which additionally shows the calibration curves in the form of a graph (see Sec- tion 7.2.4).

Such a report can also be exported at a later date with the calibration data of each stored electrode Id.

cal. interval OFF, 1...999 h

The pH/Ion Meter can automatically remind you about any recalibration of the pH electrode which is due. This means that if a calibration is carried out with a preset calibration interval then, when this interval has elapsed, a message will appear on the display:

cal.interval expired

This message remains and will be printed out on every measuring point report until a new calibration has been carried out.

no. of buffers 1, 2...9

Up to 9 buffers can be used for the pH calibration. If calibration is carried out with only one buffer then the program will use the theoretical

value of 100.0% for the slope. This also applies when a calibration with

several buffers is canceled with buffer has been measured and then confirmed with

after the first

If three or more buffers are used then the variance will be included in the calibration data. More detailed information about the evaluation is given in Section 9.2.

buffer type: Metrohm, NIST, DIN, Fisher, Fluka-BS, Mettler, Merck Tit., Merck Cer., Beckman, Radiometer, Baker, Hamilton, Precisa, special, own, mixed

For the automatic temperature-specific buffer recognition during the calibration and for the electrode test, information about the type of buffer used is required. In the pH/Ion Meter the temperature-dependent pH values of reference buffer solutions and technical buffer solutions from some suppliers are stored. Such a buffer table for Metrohm buffers looks like this:

6.2 pH measurement (pH mode)

780/781 pH/Ion Meter, Manual

Metrohm buffers

T [°C]

pH 4.00

pH 7.00

pH 9.00

<CLEAR>

negative

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95

3.99

4.00

4.01

4.02

4.03

4.04

4.06

4.07

4.09

4.11

4.13

4.15

4.18

4.20

4.23

7.11

7.08

7.06

7.04

7.02

7.00

6.99

6.98

6.97

6.98

6.99

7.00

7.01

7.02

9.27

9.18

9.13

9.08

9.04

9.00

8.96

8.93

8.90

8.87

8.84

8.81

8.79

8.76

8.74

8.73

8.71

8.70

8.68

8.67

The other stored buffer tables are described in Section 9.4. During the calibration the pH/Ion Meter shows the type and temperature-specific pH value of the recognized buffer. For temperatures within the 5 °C steps the pH value is linearly interpolated.

buffer type: special

If you would like to use different buffers from those described, then you require the exact pH value of each buffer at the temperature used for calibration. These pH values can be entered here. During the calibration they can again be adapted before each measurement.

buffer type: own

If further temperature-specific pH values are known for such buffers then under

own you can enter up to five such pH(T) series at

steps of 5 °C. The query starts at 0 °C and finishes at 95 °C or earlier, if '

OFF' is entered with

If you do not know the pH values for individual temperatures just enter zero. However, you can also calculate these values by linear interpolation and enter them. Missing pH definitions will otherwise be shown during the calibration by tion will then be interrupted with the error message

not defined

values; the calibra-

buffer

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

buffer type: mixed

A further way of using the stored buffer table is to combine a maximum of five different buffer types to form a new series. You can make your selection from all the stored buffers described in Section 9.4.

A general rule is that you can only calibrate in defined temperature ranges, as otherwise the error message:

buffer not defined

appears. If you use more than two buffers for the calibration then you can use certain buffers several times in order to give them a better statistical weight.

low lim.slope 0.1...95.00...999.9 % up lim.slope 0.0...103.0...999.9 % low lim.pH(0 -99.999...6.40...99.999 up lim.pH(0) -99.999...8.00...99.999

)The most important calibration data such as slope and pH(0) must lie within the limits defined here in order for them to be automatically adopted. The given default values for the slope correspond to the quality criteria of a "passing electrode" in the electrode test (see Section 8.6).

If one of the values of the calibration data lies outside these limits then at the end of the calibration the following message will appear:

data out of limits

; you can then accept or reject the results.

cal.

offset Uoff state: OFF, ON

offset Uoff -2200.0...0.0...2200.0 mV

The automatic buffer recognition of the pH/Ion Meter assumes an offset potential of 0 ± 30 mV for the electrode used. Ag/AgCl reference electrodes normally meet this requirement. If other reference systems are used, e.g. a calomel electrode, then the offset potential may be outside this range. This means that for correct buffer recognition this variation must be compensated by entering the specific offset potential Uoff. For the pH measurement itself this parameter is unimportant.

6.2 pH measurement (pH mode)

780/781 pH/Ion Meter, Manual

: └ state

6.2.3 Limits pH

PARAMETER pH

├ limits pH

In the direct measuring modes the pH/Ion Meter has a limits function which allows the control of the parameter to be monitored. The control signals are transmitted via the MSB connection to the optional remote interface (6.2148.010) (see Section 9.5). Out of limits conditions are al- so shown on the display and documented in the report.

state: ON, OFF

u.limit pH -19.999...14.000...19.999 u.hyst. pH -19.999...0.020...19.999 l.limit pH -19.999...0.000...19.999 l.hyst. pH -19.999...0.020...19.999

The exact way in which the limits function works is described in Section 7.4 independent of the mode.

6.2.4 Limits T

PARAMETER pH

├ limits T

As well as the primary measuring quantity pH, the temperature can also be controlled by the limits function. However, you should only activate the limits function for the temperature when a temperature sensor is connected, as otherwise an error message will appear.

state: ON, OFF

u.limit -999.9...100.0...999.9 °C u.hyst. -999.9...0.2...999.9 °C l.limit -999.9...0.0...999.9 °C l.hyst. -999.9...0.2...999.9 °C

A detailed description of the remote lines is given in Section 9.5. The exact way in which the limits function works is described in Section 7.4 independent of the mode.

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

└ right marg.T

TIP !

. By exchanging the limits the plot of the particular quantity

: └

6.2.5 Plot parameters

PARAMETER pH

├ plot parameters

: ├ left mar. pH ├ right mar. pH ├ left marg.T

The two directly recorded measuring quantities pH and temperature can be printed out as a function of time in a plot. Under

meas. value

tion 5.2). The scales of the measured values axes are determined by the following limits.

left mar. pH -19.9...0.0...19.9 right mar. pH -19.9...14.0...19.9 left marg.T -999...20...999 °C right marg.T -999...30...999 °C

The value for the right-hand limit of a plot must not necessarily be the larger one can be mirrored.

CONFIG/print

the print criterion 'plot' must be selected (see Sec-

6.2.6 Preselections

PARAMETER pH

├ preselections

req.ident.: id1, id1 & id2, OFF

For sample identification you can document each measured value with two Ids in the report header. These can either be predefined under

CONFIG/report and included in each report or, depending on the pre-

selections setting, they can be requested before each measurement.

Please note that sample identifications requested as a preselection before the measurement will also be stored as an entry under

FIG/report

measurement.

req.ident

CON-

. This means that they are again available for the next

6.2 pH measurement (pH mode)

780/781 pH/Ion Meter, Manual

└ report

6.2.7 Electrode test

PARAMETER pH

└ electrode test

├ electrode type ├ temperature

The pH/Ion Meter can carry out a pH electrode test, which permits the quality of the electrode used to be evaluated. A detailed description of the electrode test is given in Section 8.6.

electrode type: standard, gel, non-aq., own

Various types of pH electrodes have different evaluation criteria. For the three most commonly used Metrohm pH electrode types the tolerances are stored in the pH/Ion Meter: standard electrodes, gel electrodes and non-aqueous electrodes.

electrode type: own

If you wish to define your own tolerances then select ' can now enter the limits for the quality features '

electrode

', 'good electrode' and 'passing electrode'.

own'. You

excellent

An explanation of the individual limits is given in Section 8.6.3.

Regardless of the electrode evaluation, if '

own' is selected as the

electrode type then you can also edit the limits for the offset potential Uoff. This allows the electrode test to be carried out with pH electrodes which, even with an Ag/AgCl reference electrode, show a clearly shifted zero potential (e.g. antimony electrode). The use of other reference electrodes can also result in changed zero potentials.

temperature 0.0...25.0...99.9 °C

If no temperature sensor is connected then enter the temperature at which the buffer will be measured here.

report: OFF, short, full, line

After the electrode test you can automatically output the result in the form of report. You can choose between the 'short' version containing all the relevant data and the 'full' version, which also shows the measuring curves as a graph. If you are only interested in the evaluation of the electrode itself then select '

excellent electrode'. If no printer is connected then please select

OFF'.

line'. Only the result will be printed out, e.g.

The report of the last pH electrode test can also be printed out later with

(see Section 4.3).

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

└

6.3 Temperature measurement (T mode)

6.3.1 Measuring parameters

PARAMETER T

├ measuring parameters

: ├ electr.id ├ drift ├ method ├ delta measurement

stirrer

The measuring parameters describe the settings of direct importance for the measurement.

electr.id 12 ASCII characters

You can assign any name you want to the connected temperature sensor. This sensor Id is then contained in the report header for measured values.

drift 0.5...1.0...999.9 °C/min, OFF

If this drift condition is not fulfilled then this is indicated by two constantly blinking triangles in the display.

An active drift control increases the reproducibility of the measurements as a constant condition is used to define the measured result. A smaller value for the measuring parameter Drift requires a more stable measuring signal than a larger one. The set measuring parameter is also proportional to the measuring uncertainty of the measured value obtained.

method 8 ASCII characters

OFF', as otherwise no result will be ex-

delta measurement: ON, OFF

The delta measurement permits the display of the measured value relative to a freely selectable constant reference value:

reference -999.9...0.0...999.9 °C

6.3 Temperature measurement (T mode)

780/781 pH/Ion Meter, Manual

MEAS/PRINT

drift-controlled

: └ state

RAMETER T/limits T

). The reference value is not included in the re-

PA-

port. However, should you still want to document it then you should also produce a parameter report (see Section 7.2.7).

stirrer: ON, OFF, control

FIG/peripheral units

then the stirring rate can also be selected:

CON-

stirring rate 1...5...15

If you want your measurement to be made without stirring but still want to stir the solution before the measurement then you should select the

control setting. In this way you can trigger a stirring sequence before

the start of each measurement with

6.3.2 Limits T

prestir pause 0...99999 s stir time 0...99999 s poststir pause 0...99999 s

The prestir and poststir pauses represent waiting periods in which stirring does not take place. The measurement itself only starts when the complete stirring sequence has ended. Please note that this parameter is binding for the report output and for storing a measured value. Therefore when you start a measurement with <

> the stirrer will be switched on and off accordingly. This is why you should preferably carry out

measurements (see Section 5.2 and Sec-

tion 5.3).

PARAMETER T

├ limits T

state: ON, OFF

u.limit -999.9...100.0...999.9 °C u.hyst. -999.9...0.2...999.9 °C l.limit -999.9...0.0...999.9 °C l.hyst. -999.9...0.2...999.9 °C

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

PARAMETER T

└ right mar.

TIP !

└ req.ident

The exact way in which the limits function works is described in Section 7.4 independent of the mode.

You should only activate this limits function for the temperature if a temperature sensor is connected, as otherwise the following message will appear

6.3.3 Plot parameters

├ plot parameters

: ├ left mar.

The measured temperature can be printed out as a function of time in a plot. Under must be selected (see Section 5.2). The scales of the measured values axes are determined by the following limits.

left mar. -999.9...0.0...999.9 °C right mar. -999.9...100.0...999.9 °C

The value for the right-hand limit of a plot must not necessarily be the larger one. By exchanging the limits the plot can be mirrored.

limit error

CONFIG/print meas. value the print criterion 'plot'

6.3.4 Preselections

PARAMETER T

└ preselections

req.ident: id1, id1 & id2, OFF

For sample identification you can document each measured value with two Ids in the report header. These can either be predefined under

CONFIG/report and included in each report or, depending on the Pre-

selections setting, they can be requested before each measurement.

Please note that sample identifications requested as a preselection before the measurement will also be stored as an entry under

FIG/report

measurement.

CON-

. This means that they are again available for the next

6.4 Potential measurement (U mode)

780/781 pH/Ion Meter, Manual

└

6.4 Potential measurement (U mode)

6.4.1 Measuring parameters

PARAMETER U

├ measuring parameters

: ├ electr.id ├ drift ├ method ├ delta measurement

stirrer

The measuring parameters describe the settings which are of direct importance for the measurement.

electr.id 12 ASCII characters

You can assign any name you like to the connected pH electrode. The electrode Id will then be included in the report header for the output of measured values.

drift 0.1...1.0...999.9 mV/min, OFF

If this drift condition is not fulfilled then this is indicated by two constantly blinking triangles in the display.

An active drift control increases the reproducibility of the measurements as a constant condition is used to define the measured result. A smaller value for the measuring parameter Drift requires a more stable measuring signal than a larger one. The set measuring parameter is also proportional to the measuring uncertainty of the measured value obtained.

method 8 ASCII characters

OFF', as otherwise no result will be ex-

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

MEAS/PRINT

drift-controlled

: └

delta measurement: ON, OFF

The delta measurement permits the display of the measured value relative to a freely selectable constant reference value:

reference -2200.0...0.0... 2200.0 mV

RAMETER U/limits U

). The reference value is not included in the re-

PA-

port. However, should you still want to document it then you should also produce a parameter report (see Section 7.2.7).

stirrer: ON, OFF, control

FIG/Peripheral units

then the stirring rate can also be selected:

CON-

6.4.2 Limits U

stirring rate 1...5...15

If you want your measurement to be made without stirring but still want to stir the solution before the measurement then you should select the

control setting. In this way you can trigger a stirring sequence before

the start of each measurement with

prestir pause 0...99999 s stir time 0...99999 s poststir pause 0...99999 s

> the stirrer will be switched on and off accordingly. This is why you should preferably carry out

measurements (see Section 5.2 and Sec-

tion 5.3).

PARAMETER U

├ limits U

state

6.4 Potential measurement (U mode)

780/781 pH/Ion Meter, Manual

└ right mar.

TIP !

└

state: ON, OFF

u.limit -2200.0...1000.0...2200.0 mV u.hyst. -2200.0...2.0...2200.0 mV l.limit -2200.0...-1000.0...2200.0 mV l.hyst. -2200.0...2.0...2200.0 mV

The exact way in which the limits function works is described in Section 7.4 independent of the mode.

6.4.3 Plot parameters

PARAMETER U

├ plot parameters

: ├ left mar.

The measured potential can be printed out as a function of time in a plot. Under must be selected (see Section 5.2). The scales of the measured values axes are determined by the following limits.

CONFIG/print meas.value the print criterion 'plot'

Left mar. -2200.0...-1000.0...2200.0 mV Right mar. -2200.0...1000.0...2200.0 mV

The value for the right-hand limit of a plot must not necessarily be the larger one. By exchanging the limits the plot can be mirrored.

6.4.4 Preselections

PARAMETER U

└ preselections

req.ident: id1, id1 & id2, OFF

For sample identification you can document each measured value with two Ids in the report header. These can either be predefined under

CONFIG/report and included in each report or, depending on the Pre-

selection setting, they can be requested before each measurement.

Please note that sample identifications requested as a preselection before the measurement will also be stored as an entry under

FIG/report

measurement.

req.ident

CON-

. This means that they are again available for the next

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

direct ion measurement

standard addition

sample additi-

meas.type

└ conc.unit

6.5 Direct ion measurement (781 only: Conc mode)

6.5.1 Type of measurement

PARAMETER Conc

├ meas.type

The type of measurement describes the analytical principle of ion measurement.

meas.type: direct, std.add, smpl.add

In general a differentiation is made between direct measurement and the standard or sample addition methods. The selection of the method parameters depends on the measurement type which has been chosen. All the method parameters for scribed in this section. The descriptions of the

measuring parameters and calculation parameters which this

section contains also apply to the

types of ion measurement. As a result the following explanation of

the parameters for the standard and sample addition in Section limited to the specific method parameters.

ion parameters,

and

are de-

6.6 is

Please note that changing this Conc parameter clude a change of the current method. Within the mode Conc a method contains all parameter settings.

6.5.2 Ion parameters

PARAMETER Conc

├ ion parameters

: ├ ion type ├ ion name ├ ion charge

The ion parameters describe the name, charge and concentration units of the ion to be determined.

Ion: Ag(+1), BF4(-1), Br(-1), Ca(+2), Cd(+2), Cl(-1), CN(-1), Cu(+2), F(-1), I(-1), K(+1), Na(+1), NH4(+1), NO2(-1), NO3(-1), Pb(+2), S(-2), SCN(-1), SO4(-2), own

The name of the analyte can be selected here. The additional option

own' allows the analyte to be determined to be given its own name

and charge:

does not in-

ion name 7 ASCII characters

ion charge -9...-1, 1...9

6.5 Direct ion measurement (781 only: Conc mode)

780/781 pH/Ion Meter, Manual

└ stirrer

<SE-

LECT>

<CAL.DATA>

conc.unit: mol/L, %, ppm, g/L, mg/L, µg/L, mEq/L, own

The analyte concentration unit is defined here. It is used in both the calibration and the measurement itself.

Under '

own' you can also define your own unit with 5 ASCII characters:

unit 5 ASCII characters

Please note that this unit does not form part of the measured value itself but is only a supplement. This means that it cannot be used for calculation, for example to compensate for changes in order of magnitude. For this reason the concentration information in the following method parameters is given without mentioned the unit.

6.5.3 Measuring parameters

PARAMETER Conc

├ measuring parameters

: ├ electr.id ├ drift ├ temperature* ├ method ├ delta measurement

(* only appears if no temperature sensor is connected)

The measuring parameters describe the settings which are of direct importance for the measurement.

electr.id: 12 ASCII characters

You can assign any name you want to the connected ion-selective electrode. This electrode Id is then contained in the report header for measured values. Each time that the electrode is calibrated the resulting calibration data will be assigned to this entered electrode Id.

In this way you can enter several electrode Ids for each type of ion. This allows you to switch between various electrodes and to select their associated calibration data. However, a requirement is that each new electrode Id is linked with a new calibration. Then you can use

under the measuring parameter electr.id to select one of the stored electrode Ids which has been calibrated with the current type of ion.

In order to delete an electrode Id and the calibration data linked with it this must be reset under

7.1.2).

tion

(Reset cal., see Sec-

drift: 0.1...1.0...999.9 mV/min, OFF

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

measured value is to be stored or documented by printing a report (see print criterion and storage criterion in Section 5.2 and Section 5.3). Please note that for a drift-controlled measured value recording this drift parameter must not be set to '

OFF', as otherwise no result will be ex-

ported.

If this drift condition is not fulfilled then this is indicated by two constantly blinking triangles in the display.

An active drift control increases the reproducibility of the measurements as a constant condition is used to define the measured result. A smaller value for the measuring parameter Drift requires a more stable measuring signal than a larger one. The set measuring parameter is also proportional to the measuring uncertainty of the measured value obtained.

Please note that the drift condition defined here and the temperature parameter described below do not apply to the calibration of the direct concentration measurement and, if necessary, must be set separately under the calibration parameters (see Section 6.5.5).

temperature -999.9...25.0...999.9 °C

The correct recording of the measuring temperature is required for the automatic correction of the electrode slope. If no temperature sensor is connected you can enter the temperature of the solution under investigation here. Information about the measuring temperature also makes sense for the documentation of an ion-selective measurement. This manually determined temperature is then indicated by the suffix '

' in the report header.

manu-

method 8 ASCII characters

delta measurement: ON, OFF (only measurement type: direct)

The delta measurement permits the display of the measured value relative to a freely selectable constant reference value:

reference -1.00E+30...0.00...1.00E+30

RAMETERS Conc/limits Conc

). The reference value is not included in

PA-

the report. However, should you still want to document it then you should also produce a parameter report (see Section 7.2.7).

stirrer: ON, OFF, control

6.5 Direct ion measurement (781 only: Conc mode)

780/781 pH/Ion Meter, Manual

MEAS /PRINT

ENTER

PARAMETER Conc

└ smpl.size unit

rer has been connected and the settings made under CON-

FIG/peripheral units

then the stirring rate can also be selected:

stirring rate 1...5...15

If you want your measurement to be made without stirring but still want to stir the solution before the measurement then you should select the

control setting. In this way you can trigger a stirring sequence before

the start of each measurement with

prestir pause 0...99999 s stir time 0...99999 s poststir pause 0...99999 s

The prestir and poststir pauses represent waiting periods in which stirring does not take place. The measurement itself only starts when the complete stirring sequence has ended.

Please note that this parameter is binding for the report output and for storing a measured value. Therefore when you start a measurement with <

> or an addition sequence with <

> the stirrer will be switched on and off accordingly. This is why you should preferably carry out drift-controlled measurements for the direct determination of the concentration (see Section

5.2 and Section 5.3).

6.5.4 Calculation parameters

├ calculation parameters

: ├ smpl.size ├ V total ├ factor

The calculation parameters can be used for directly including sample preparation data for the automatic calculation of the analytical result. In this way the measured value shown will refer to the concentration of the ion in the original sample and not in the sample solution to be measured.

smpl.size 0.0001...99999.9 (mL or g), OFF V total 0.001...100.0...9999.9 mL factor -1.00E+30...1.0...1.00E+30 smpl.size unit: mL, g

smpl.size describes the volume or weight of the sample under inves-

tigation, depending on the selected want to use this parameter then set it to '

smpl.size unit. If you do not

OFF'.

V total represents the volume of the sample solution at the start of

the measurement, e.g. after the addition of a buffer (TISAB, etc.).

The calculation of the measured value is then carried out according to the following equation:

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

)old(valueMeasured

size.smpl

factor)new(valueMeasured

total

⋅⋅=

└ V Exchange Unit 1...n

Please note that the unit of the measured value is not altered in this calculation. The Meas. value(new) will therefore always have the same unit as Meas. value (old), i.e. the unit which has been set under

CONC/ion parameters

and with which the calibration has been carried

PARAMETER

out.

For example, if you use the

/smpl.size will represent the dilution of the sample when it is larger

total

than one. It can also describe the concentration of a sample if it is smaller then one.

You can also weight out your liquid sample before dilution and then select the sample size unit g. For a correct calculation the density of the sample in g/mL should be entered as the factor.

For a more individual input of the sample data you can also have the program automatically request the sample size and sample size unit directly before each measurement (see Preselections, Section 6.5.9 and Section 6.6.2).

6.5.5 Calibration parameters

(applies only for measurement type: direct)

PARAMETER Conc

├ calibration parameters

: ├ temperature* ├ drift ├ report ├ cal.interval ├ no.of standards └ addition ┬ manual - conc.1...n └ auto ┬ min.conc. ├ max.conc.

├ V init ├ no.of Exchange Units ├ conc.1...n

smpl.size unit: mL, then the quotient

(* only appears if no temperature sensor is connected)

In the direct measurement of the concentration the calibration parameters primarily describe the exact presentation of the calibration standards. The evaluation of the calibration is described in Section 9.2.2.

temperature 0.0...25.0...99.9 °C

Just as for the measuring temperature, the calibration temperature should be entered if no temperature sensor is connected. If the measuring and calibration temperatures are different then this is absolutely necessary for the automatic temperature correction of the electrode slope. The temperature is then stored and indicated by the suffix '

ual

' in the report header.

man-

6.5 Direct ion measurement (781 only: Conc mode)

780/781 pH/Ion Meter, Manual

<MODE>

<QUIT>

<ENTER>

at least

manual

automatic

drift: 0.1...0.5...9.9 mV/min

Just like the ion measurement, the calibration is also drift-controlled. However, this drift-control cannot be switched off.

report: OFF, short, full

After the calibration you can automatically output the result in the form of report. You can choose between the ' relevant data and the '

full' version, which also shows the measuring

short' version containing all the

curves as a graph (see Section 7.2.4).

Such a report can also be printed out later together with the calibration for each stored electrode Id.

calibration interval OFF, 1...999 h

cal.interval expired

This message is retained and will be printed out on every measuring point report until a new calibration has been carried out.

no.of standards 1, 2...19

Up to 19 standards can be used for the calibration of the ion selective electrode. If only a single standard is used for the calibration then the program will use the existing value for the slope. This will also be corrected accordingly if the calibration temperature changes. This adoption of the existing slope also applies when a calibration with several standards is canceled with ard has been measured and then confirmed with

after the first stand-

However, please note that for the calibration of ion-selective electrodes

two standards should be used. The possibility of using a single standard described above should only represent an absolute exception.

If three or more standards are used then the variance will be included in the calibration data. More detailed information about the evaluation is given in Section 9.2.

addition: manual, auto

For the

addition of the standard you should enter in the next

calibration parameter lines the concentrations of the standards used (Conc.1, Conc.2, ...). This data can still be modified during the calibration sequence.

With

standard addition the pH/Ion Meter carries out the calculation of the standard concentrations, the preparation of the standard solutions and their measurement automatically. A requirement is that a Metrohm Dosimat Plus is connected (connection and Dosimat Plus

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

<ENTER>

: └

configuration see Section 2.3.3, pH/Ion Meter configuration see Section 5.6).

min.conc 1.0E-30...0.1...1.0E+30

max.conc. 1.0E-30...1.0...1.0E+30

The standard concentrations to be calculated lie within the range of these minimum and maximum concentrations. Depending on the required number of standards (see above), the pH/Ion Meter will calculate the other concentrations. The expected resulting potential difference between all the standards remains constant.

V init 0.001...100.0...999.9 mL

The initial volume of a presentation (e.g. buffer, TISAB, etc.) is entered here.

no.of Exchange Units. 1...5

It is normally a good idea to calibrate ion-selective electrodes over several concentration decades. It is possible that a single Dosimat exchange unit may not be sufficient for this. In this case you can prepare several exchange units with the corresponding different concentrations of standard solutions:

For each exchange unit you must enter the concentration of the solution it contains and the volume of the dosing cylinder. Arrange the exchange units with increasing concentration of the standard solutions.

Please make sure that all exchange units have been prepared before the start of a calibration sequence (dosing cylinders freshly filled, air bubbles removed, etc.). The request for changing the exchange unit is given on the display. This message describes the required standard concentration and volume increment at the Dosimat Plus.

After mounting and filling the prepared exchange unit, continue with

6.5.6 Limits Conc

(applies only to measurement type: direct)

PARAMETER Conc

├ limits Conc

conc.1...n 1.0E-30...100.0...1.0E+30

V Exchange Unit 1...n: 1, 5, 10, 20, 50 mL

fill dosimat, dV/dt max. dV = 1 ul, c = 2000.0 ppm

state

6.5 Direct ion measurement (781 only: Conc mode)

780/781 pH/Ion Meter, Manual

: └ state

└ right marg.T

interface (6.2148.010) (see Section 9.5). Out of limits conditions are al- so shown on the display and documented in the report.

state: ON, OFF

u.limit -1.00E+30...1.00E+30 u.hyst. -1.00E+30...2.00...1.00E+30 l.limit -1.00E+30...0.00...1.00E+30 l.hyst. -1.00E+30...2.00...1.00E+30

The exact way in which the limits function works is described in Section 7.4 independent of the mode.

6.5.7 Limits T

(applies only for Conc measurement type: direct)

PARAMETER Conc

├ limits T

Just as in the pH mode, in the Conc mode the temperature can also be monitored via the limits function in addition to the primary measuring quantities. However, you should only activate this limits function for the temperature when a temperature sensor is connected, as otherwise an error message will appear.

state: ON, OFF

u.limit -999.9...100.0...999.9 °C u.hyst. -999.9...0.2...999.9 °C l.limit -999.9...0.0...999.9 °C l.hyst. -999.9...0.2...999.9 °C

A detailed description of the remote lines is given in Section 9.5. The exact way in which the limits function works is described in Section 7.4 independent of the mode.

6.5.8 Plot parameters

(applies only to measurement type: direct)

PARAMETER Conc

├ plot parameters

: ├ left mar. ├ right mar. ├ left marg.T

The directly measured quantities concentration and temperature can be printed out as a function of time in a plot. Under

value

The scales of the measured values axes are determined by the following limits.

the print criterion 'plot' must be selected (see Section 5.2).

CONFIG/print meas.

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

TIP !

. By exchanging the limits the plot of the particular quantity

└ req.smpl.size

left mar. -1.0E+30...0.0...1.00E+30 right mar. -1.0E+30...1.00E+30 left marg.T -999...20...999 °C right marg.T -999...30...999 °C

The value for the right-hand limit of a plot must not necessarily be the larger one can be mirrored.

6.5.9 Preselections

(applies only to measurement type: direct)

PARAMETER Conc

└ preselections

├ req.ident

req.ident.: id1, id1 & id2, OFF

For sample identification you can document each measured value with two Ids in the report header. These can either be predefined under

CONFIG/Report and included in each report or, depending on the Pre-

selections setting, they can be requested before each measurement.

Please note that sample identifications requested as a preselection before the measurement will also be stored as an entry under

FIG/Report

(see Section 5.1). This means that they are again availa-

CON-

ble for the next measurement.

req.smpl.size: value, unit, all, OFF

The parameters smpl.size and smpl.size unit described in the calculation parameters (see Section 6.5.4) can also be requested for each measurement. This allows an individual sample data input.

Just as in the request for the sample identifications, the sample size requested here will also be stored under

tion parameters

and is available for the request before the next

PARAMETER Conc/calcula-

measurement.

6.6 Standard and sample addition (781 only: Conc mode)

780/781 pH/Ion Meter, Manual

standard addition

sample addition

PARAMETER Conc

meas.type

└ stop

6.6 Standard and sample addition (781 only: Conc mode)

In the ion measurement Conc mode a differentiation is made between direct measurement and the standard or sample addition and subtraction methods.

All the method parameters for direct concentration determination are described in Section 6.5. The descriptions of the ion parameters,

measuring parameters and calculation parameters given there

also apply to the measurement. This is why this section contains only the method parameters which apply only to these types of measurement.

├ meas.type

meas.type: direct, std.add, smpl.add

The measurement type describes the analytical principle of ion measurement. Select '

std.add' if the analysis is to be carried out accord-

ing to the standard addition method, i.e. by the addition of defined standard solutions to the sample. For the sample addition method, the multiple addition of the sample solution to a standard solution, select

smpl.add'.

and

types of ion

Please note that changing this Conc parameter clude a change of the current method. Within the mode Conc a method contains all parameter settings.

6.6.1 Standard / Sample addition

PARAMETER Conc

├ standard addition / sample addition

: ├ type ├ conc.std. ├ report └ addition ┬ manual ┬ no.of additions │ ├ increment 1...n

│ └ stop V ├ auto dos ┬ dos.rate │ ├ no.of additions

│ ├ V Exchange Unit

│ ├ increment 1...n

│ └ stop V

└ auto ┬ delta U

├ no.of additions ├ V Exchange Unit

├ dos.rate

does not in-

The exact technique of standard and sample addition in the Conc mode is described by the parameters selected under

tion

and sample addition:

standard addi-

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

addition

subtraction

<MODE>

<QUIT>

<ENTER>

at least

type: add, sub

In general – and also in this Manual – when dealing with standard and sample addition techniques it is possible to carry out a standard or sample

which is described. It is also

, for example by

precipitation reactions. The appropriate type is set here.

conc.std. 1.0E-30...1.0...1.0E+30

The concentration of the standard solution used is to be entered here, regardless of whether it is to be added during standard addition or already present for sample addition.

report: OFF, short, full, line

After the addition run you can automatically output the result in the form of report. You can choose between the ' relevant data and the '

full' version, which also shows the measuring

curves as a graph (see Section 7.2.5). The '

short' version containing all the

line' setting supplies re-

ports with the most important data in the same form as in the measuring point reports for direct measurements.

The 'short' and 'full' reports can also be produced later under

addition: manual, auto dos, auto

Standard or sample addition can be carried out in various ways:

manual

The standard or sample solution is added manually at defined volume increments.

no.of additions 1, 2, 3,...19

The number of additions is entered here. If only one addition is made then the program will adopt for the slope the existing value from the current calibration data of the electrode used. This will also be corrected accordingly if measuring temperature changes in comparison to the calibration temperature. This adoption of the existing slope also applies when a standard or sample addition with several additions is canceled with ter the first addition and then confirmed with

af-

However, please note that, as for the calibration of ion-selective electrodes,

two additions should be made (three to five or even more would be better). The possibility of terminating the addition after a single standard or sample addition as described above should only represent an absolute exception.

increment 1...n 1.0E-30...0.1...999.9 mL

The volume increment for each addition is entered here.

6.6 Standard and sample addition (781 only: Conc mode)

780/781 pH/Ion Meter, Manual

TIP !

It is possible to alter this parameter during an addition run. For example, before confirming the volume increment you can add

otential difference is

shown on the display. Then confirm the volume to be added; the

the solution during the run until a certain p

corresponding potential will be measured after each addition. This can be a great help, for example when checking the suitability of a standard for this method.

stop V 0...99.99...9999.9 mL

For the manual addition no check will be carried out whether the stop volume is exceeded or not in contrary to

auto (see below).

auto dos and

auto dos and auto

If a Dosimat Plus is used then the standard or sample addition can be carried out automatically (connection and Dosimat Plus configuration see Section 2.3.3, pH/Ion Meter configuration see

Section 5.6). You can chose between two methods: under auto dos you can enter the individual volume increments for the add-

ed solution; under auto these additions are made automatically so that a constant potential difference always results.

The common parameters are:

dos.rate fast, medium, slow no.of additions 1, 2, 3,...19 V Exchange Unit 1, 5, 10, 20, 50 mL stop V 0...99.99...9999.9 mL

The dosing rate can be set in three steps via

auto dos' the pH/Ion Meter checks at the start of the auto-

In '

dos.rate.

matic standard and sample addition whether the sum of the volume increments exceeds the set stop volume

Stop V. If this is

the case then the following message will appear:

V add too large

Under '

auto' this check is carried out during the automatic ad-

dition and, if necessary, will cause the run to be stopped with the message:

check working cond.

Depending on the automatic addition method the following parameters must also be defined:

6 Methods / Parameters

780/781 pH/Ion Meter, Manual

<MODE>

PARAMETER Conc

└ activate pulse

auto dos

increment 1...n 1.0E-30...0.1...999.9 mL

The particular volume increment must be entered for each addition of the standard or sample solution.

auto

delta U 1...10...999 mV

During an addition you can terminate the run prematurely with it

be used for the calculation of the result. This manual termination will be marked in the report.

6.6.2 Preselections

└ preselections

├ req.ident ├ req.smpl.size

req.ident: Id1, Id1 & Id2, OFF

For sample identification you can document each measured value with two Ids in the report header. These can either be predefined under

CONFIG/Report and included in each report or, depending on the Pre-

selections setting, they can be requested before each measurement.

Under

auto the required potential difference must be entered.

Please note that the Dosimat Plus must be properly prepared before the start of an addition run (cylinder freshly filled, air bubbles removed, etc.).

; only the additions which have already been measured will

Please note that sample identifications requested as a preselection before the measurement will also be stored as an entry under

FIG/Report

. This means that they are again available for the next

CON-

measurement.

req.smpl.size : value, unit, all, OFF

The sample size and sample size unit parameters described under the calculation parameters (see Section 6.5.4) can also be requested before each measurement. This allows a more individual input of the sample data.

6.6 Standard and sample addition (781 only: Conc mode)

780/781 pH/Ion Meter, Manual

7 Various functions

780/781 pH/Ion Meter, Manual

CAL.DATA

ADD.DATA

CAL. DA T A

└ curve

7 Various functions

This section describes various functions of the pH/Ion Meter which cannot be assigned to individual modes.

7.1 Calibration and addition/subtraction data

The current pH calibration data can be called up at any time with the < concentration calibration (< tion data (<

A detailed description of the evaluation of the calibration and addition/subtraction measurements for the calculation of this data can be found in Section 9.2.

An overview appears which, depending on the measuring mode and calibration data, can have a different composition.

For example, if no calibration has yet been carried out for a new elec-

trode Id then only the theoretical calibration data slope = 100.00% and

pH(0) = 7.000 will be shown and taken into account for the measurement.

> key. For the 781 pH/Ion Meter the same applies to the

>) in the Conc mode.

>) and the addition or subtrac-

7.1.1 pH calibration data

CAL.DATA

├ electr.id ├ method ├ slope ├ pH(0) ├ temperature ├ temp.sensor ├ c.dat. ├ cal.interval ├ variance ├ buffer type ├ no.of buffers ├ cal.table ├ b1 ├ b2

├ bn

electr.id

If an electrode Id has been selected or entered under PARAMETER pH/

measuring parameters/electr.id

be shown here. The calibration data apply only to this electrode and will change when a new electrode Id is set under the above measuring parameters (see Section 6.2.2).

before the calibration then it will

7.1 Calibration and addition/subtraction data

780/781 pH/Ion Meter, Manual

method

The calibration parameters set under PARAMETER pH/calibration

parameters

form part of the method parameters. The corresponding method name will be shown here if the calibration data has been obtained with this method and the resulting quantities

slope and pH(0)

have not been altered since. If no method name has been issued before the calibration (see Section 6.1) then '

********' will appear here.

slope

The slope of the linear calibration curve obtained during the calibration will be shown here as a percentage. This is a relative quantity which is based on the temperature-specific value of the Nernst constant (e.g.

59.16 mV at 25 °C). Without a calibration, or after a single buffer calibration, this is set to 100 %.

This value can be altered manually for test purposes. However, afterwards the information about the method will be missing from the list and from the calibration data report. The calibration date and time will be updated and the temperature information and the calibration table (see below) will be removed. In addition this action will be documented by the entry '

manual' under CAL.DATA/variance.

pH(0)

This is the second characteristic quantity of the calibration curve. pH(0) is the pH value at 0 mV. It can also be altered manually for test purposes. The other entries under

CAL.DATA will be altered in the same way as

for a manual alteration of the slope (see above).

temperature

The calibration temperature is shown here.

temp.sensor

If the calibration temperature has been determined automatically by a connected temperature sensor then its type will be shown here

Pt1000' or 'NTC'). A manually entered temperature for the calibration

(' will be indicated accordingly ('

manual').

c.dat.

The date and time of the calibration is shown here.

cal.interval

If a calibration interval has been defined under PARAMETERS pH/ cal-

ibration parameters/cal.interval

can be used together with the calibration time given under

then it will be shown here. It

c.dat. to

estimate the time that the next calibration is due.

7 Various functions

780/781 pH/Ion Meter, Manual

QUIT

SELECT

variance

If at least 3 calibration buffers have been used then the calibration function will be calculated as a compensation curve according to the principle of the smallest mean-square error (linear regression). The resulting variance will be given here. A more detailed explanation of these calculations is given in Section 9.2.1.

Each subsequent manual alteration of the calibration data pH(0) and slope will be documented by the entry '

manual' against these parame-

ters.

buffer type

The type of buffer defined in the calibration parameters at the time when calibration was carried out is shown here.

no.of buffers

The number of buffers actually measured is shown here. This can be lower than that given in the calibration parameters, as a calibration can be terminated prematurely with <

>; only the buffers which have already been measured will then be used for the calculation of the calibration data.

cal.table: original, delete n, reset cal

This entry can be used to delete individual buffers from the calibration table (' ('

delete n') or to delete all the calibration data of an electrode Id

reset cal').

original

If you use < buffer data previously deleted with '

> to chose the option 'original' then all the

delete n' will be reinserted in

the calibration table and used for calculating the calibration data.

delete n

From a calibration list containing at least 3 buffer entries you can remove individual buffer data by selecting '

delete n' and enter-

ing the number of the buffer to be deleted in the following line:

delete n: 1..9

The deleted buffer will then be indicated in the calibration table by

deleted'. The measuring points of deleted buffers are also indi-

' cated in the graphical display by an 'o' instead of a '+'.

You can reinsert all deleted buffers in the calibration table with the option '

original'.

7.1 Calibration and addition/subtraction data

780/781 pH/Ion Meter, Manual

QUIT

reset cal

With this option you can reject all the calibration data of an electrode Id. They are then in the same state as before the first calibration (slope = 100%, pH(0) = 7).

Although the electrode Id is retained, it cannot be selected under

PARAMETER pH/measuring parameters/electr.id until it

has been calibrated again.

b1, b2...bn

For each calibration buffer the pH value used and the measured potential are given. The given value for the pH is taken from the stored series of buffers of the buffer type selected in the calibration parameters (see Section 9.4). The pH values for temperatures within the given 5 °C steps are calculated by linear interpolation.

A buffer which has been deleted by here by '

deleted'.

cal.table: delete n is shown

curve < –> >

If at least 2 calibration buffers have been used then the calibration curve will be shown as a graph here. The graphics display is accessed with <



This display is exited with <

7 Various functions

780/781 pH/Ion Meter, Manual

CAL. DA T A

7.1.2 Conc calibration data (781 pH/Ion Meter only)

CAL.DATA

├ ion type ├ electr.Id ├ method ├ slope ├ E(0) ├ c(blank) ├ temperature ├ temp.sensor ├ c.dat. ├ cal.interval ├ variance ├ no.of standards ├ cal.table ├ st1 ├ st2

├ stn

└ curve

ion type

The analyte ion which has been defined during the calibration under

PARAMETER Conc/ion parameters is shown here. As with the follow-

ing electrode Id, the current calibration data changes as the ion parameter changes.

electr.id

If an electrode Id has been entered or selected before the calibration under

PARAMETERS Conc/measuring parameters/electr.id then it

will be shown here. Electrode Ids can be defined for a particular type of ion. The calibration data will apply to this electrode only and will change when a new electrode Id is set under the above measuring parameters (see Section 6.5.5).

method

The calibration parameters set under PARAMETER Conc/calibration

parameters

form part of the method parameters. The appropriate method name will be shown here when the calibration data have been determined using this method and the resulting quantities

c(blank) have not been altered since. If no method name has

and been assigned before the calibration (see Section 6.1), then '

slope, E(0)

********'

will appear here.

slope

The slope of the calibration function obtained during the calibration will be shown here in mV. With no calibration this will be set to the theoretical value of +59.2 mV or -59.2 mV per ion charge at 25 °C.

This value can be altered manually for test purposes. However, afterwards the information about the method will be missing from the list

7.1 Calibration and addition/subtraction data

780/781 pH/Ion Meter, Manual

and from the calibration data report. The calibration date and time will be updated and the temperature information and the calibration table (see below) will be removed. In addition this action will be documented by the entry '

manual' under CAL.DATA/variance.

E(0)

This is the second characteristic quantity of the calibration function. E(0) is the potential at log(c) = 0, i.e. the U-axis intercept of the calibration function in the U/log c plot. A more detailed explanation of the calculation of the calibration data is given in Section 9.2.2.

E(0) can also be altered manually for test purposes. The other entries under

CAL.DATA will then be altered in the same way as for a manual

alteration of the slope (see above).

c(blank)

This is the third characteristic quantity of the concentration calibration function. To a certain extent it reflects the curvature of the otherwise linear calibration function at the lowest concentrations. It is only calculated when at least three standards have been measured (see also Sec- tion 9.2.2). If the value for c(blank) is sufficiently small, i.e. if the influence of this quantity on the later result can no longer be measured, then it will be set as zero. Instead the variance will then be calculated even when only three standards have been measured (see below).

c(blank) can also be altered manually for test purposes. The other entries under

CAL.DATA will then be altered in the same way as for a

manual alteration of the slope (see above).

temperature

The calibration temperature is shown here.

temp.sensor

If the calibration temperature has been determined automatically by a connected temperature sensor then its type will be shown here

Pt1000' or 'NTC'). A manually entered temperature for the calibration

(' will be indicated accordingly ('

manual').

c.dat.

The date and time of the calibration will be shown here.

cal.interval

If a calibration interval has been defined under PARAMETER Conc/

Calibration parameters/cal.interval

It can be used together with the calibration time given under

then it will be shown here.

c.dat. to

estimate the time that the next calibration is due.

Metrohm 781 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1 Introduction

1.1 Instrument description

1.2 Parts and controls

1.3 Information about this Manual

1.3.1 Notation and pictograms

1.4 Safety information

1.4.1 Electrical safety

1.4.2 General handling rules

2 Installation

2.1 Instrument setup

2.1.1 Packaging

2.1.2 Checks

2.1.3 Location

2.2 Connecting the accessories

2.3 Connecting optional devices

2.3.1 Connecting the 801 Magnetic Stirrer

2.3.2 Connecting the 802 Rod Stirrer

2.3.3 Connecting a Dosimat Plus (only 781)

2.3.4 Connecting a sample changer

2.3.5 Connecting a printer

2.3.6 Connecting a computer

2.4 Connecting the electrodes and sensors

2.5 Mains connection

2.6 Switch on

2.7 Initial configuration

3 Short operating tutorial

3.1 pH measurement

3.1.1 Requirements

3.1.2 Preparations

3.1.3 pH calibration

3.1.4 pH measurement

3.2 Determination of an ion concentration (only 781: Conc mode)

3.2.1 Requirements

3.2.2 Preparations

3.2.3 Calibrating the fluoride ISE

3.2.4 Direct measurement of fluoride

4 Operation

4.1 The keypad

4.2 Operating concept

4.3 All key functions at a glance

4.4 Operating principles

4.4.1 Configuration and method parameters

4.4.2 Editing menu entries

4.4.3 Entering text

5 Configuration

5.1 Report

5.2 Printing out measured values

5.3 Storing measured values

5.4 Auxiliaries

5.5 Monitoring

5.6 Peripheral units

5.7 RS232 settings

6 Methods / Parameters

6.1 Method management

6.2 pH measurement (pH mode)

6.2.1 Measuring parameters

6.2.2 Calibration parameters

6.2.3 Limits pH

6.2.4 Limits T

6.2.5 Plot parameters

6.2.6 Preselections

6.2.7 Electrode test

6.3 Temperature measurement (T mode)

6.3.1 Measuring parameters

6.3.2 Limits T

6.3.3 Plot parameters

6.3.4 Preselections

6.4 Potential measurement (U mode)

6.4.1 Measuring parameters

6.4.2 Limits U

6.4.3 Plot parameters

6.4.4 Preselections

6.5 Direct ion measurement (781 only: Conc mode)

6.5.1 Type of measurement

6.5.2 Ion parameters

6.5.3 Measuring parameters