Gebrauchsanleitung / Operating manual

Labor-pH-Meter Laboratory pH Meter CG 842

Bedienungsanleitung Operating manual

Seite 1 Page 45

ba12242de_2

09/99

Operating Manual

Laboratory pH Meter CG 842

ba12242e_2

09/99

45

Accuracy when going to press

All details contained in this operating manual are valid data at the time of going to press. However, SCHOTT may add details for both technical and commercial reasons, or in order to fulfil legal requirements of different countries. This does not affect the characteristics described.

Warranty declaration

The designated instrument is covered by a warranty of three years from the date of purchase. The instrument warranty extends to manufacturing faults that are determined within the period of warranty. The warranty excludes components that are replaced during maintenance such as batteries, etc. The warranty claim extends to restoring the instrument to readiness for use but not, however, to any further claim for damages. Improper handling or unauthorized opening of the instrument invalidates any warranty claim. To ascertain the warranty liability, return the instrument and proof of purchase together with the date of purchase freight paid or prepaid.

Copyright

Hofheim SCHOTT Gerte GmbH 1999

Reprinting - even as excerpts - is only allowed with the explicit written authorization of SCHOTT Gerte GmbH, Hofheim. Printed in Germany.

List of contents

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
1.1 1.2 1.3 1.4 1.5 Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Sockets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Declaration of conformity . . . . . . . . . . . . . . . . . . . . . 52 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
2.1 Authorized use . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 2.2 General safety instructions . . . . . . . . . . . . . . . . . . . 58

3 4

Commissioning . . . . . . . . . . . . . . . . . . . . . . . . 61 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
4.1 Switch on the instrument . . . . . . . . . . . . . . . . . . . . . 63 4.2 Measuring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 4.2.1 Measuring the pH value . . . . . . . . . . . . . . . . 65 4.2.2 Measuring the Redox voltage . . . . . . . . . . . 66 4.3 Calibrating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 4.3.1 AutoCal TEC . . . . . . . . . . . . . . . . . . . . . . . . 69 4.3.2 AutoCal DIN . . . . . . . . . . . . . . . . . . . . . . . . . 71 4.3.3 ConCal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 4.4 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Maintenance, cleaning, disposal . . . . . . . . . . 77

6 7

What to do if... . . . . . . . . . . . . . . . . . . . . . . . . . 79 Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

47

List of contents

48

Overview

Overview

The compact CG 842 precision pH meter lets you perform pH measurements rapidly and reliably. The CG 842 provides the highest degree of operating comfort, reliability and measuring safety for all applications. The proven calibration procedures and special AutoRead function support your work with the pH meter. 3

1 Keypad 2 Display 3 Sockets

Note The measuring instrument can also be delivered as part of a set. Information on this and other accessories is available in the SCHOTT general catalog.

49

Overview

1.1

Keyboard

Switch measuring instrument ON/OFF <on/off> Select measuring mode <pH> Call up calibration procedure <CAL> Activate/deactivate AutoRead <auto read> Reduce values, scroll <t> Confirm inputs, start AutoRead <run/enter> Increase values, scroll < s>

50

Overview

1.2

Display
Status line Measured value display

Function and temperature display

1.3

Sockets

4
1 Socket according to DIN 19262/BNC 2 Pt1000/NTC30 connector for pH combined electrodes with temperature probe 3 Reference electrode connector 4 Connector for plug-in power supply (optional)

Caution Only connect probes to the instrument that cannot feed excessive voltages or currents (> SELV and > circuit with current limiter). Almost all commercial electrodes - especially SCHOTT electrodes - meet these requirements.

51

Overview

1.4

Declaration of conformity

29.03.99

SCHOTT Gerte GmbH Im Langgewann 5 D 65719 Hofheim am Taunus Deutschland, Germany, Allemagne

29. Mrz, March 29rd, 29, Mars, 1999

AGQSF0000-A056-00/990329

52

Overview

1.5
Ambient temperature

Technical data
- 25 C ... + 65 C 0 C ... + 55 C Annual mean: < 75 % 30 days/year: 95 % Other days: 85 % - 2.000 ... + 16.000 - 2.00 ... + 16.00 - 999.9 ... + 999.9 - 1999 ... + 1999 - 5.0 ... + 100.0 + 23.0 ... + 212.0

Storage temperature Operating temperature Allowable relative humidity

Measuring ranges and resolution

pH (resolution selectable) U [mV] T [C] T [F]

Measuring accuracy ( 1 digit)

Given as measuring uncertainty at a confidence level of 95%. All accuracies additionally depend on the accuracies of the measuring probes. pH ( 2 pH units around the calibration point) U [mV] T [C] 0.005 at + 15 C ... + 35 C 0.01 0.4 at + 15 C ... + 35 C 1 NTC 30: 0.1 PT 1000: 0.5 at 0 C ... 15 C 0.1 at 15 C ... 35 C 1 at 35 C ... 55 C T [F] NTC 30: 0.2 PT 1000: 0.9 at 32 F ... 59 F 0.2 at 59 F ... 95 F 1.8 at 95 F ... 131 F

53

Overview

Housing

Length [mm] Width [mm] Height [mm] Weight [kg] Material Interference emission (generic standard) Interference immunity (generic standard) Protective class Climatic class

230 210 70 Approx. 0.850 ABS EN 50081-1 FCC class A EN 50082-1 3, EN61010-1 2, VDI/VDE 3540

EMC and VDE norms

Test marks

TV GS, UL/CUL, CE
1

Display

Multifunctional LCD Automatically with Pt 1000/NTC (30 kW) Manual input -5 ... 99.9 C -20 ... 130 C resolution 1K

Temperature compensation

Keypad

Foil keypad (Polyester)

54

Overview

Energy supply

Batteries Runtime Mains power supply (option)

4 x 1.5 V AA type alkaline manganese batteries Approx. 3000 operating hours Connection max. overvoltage category II (valid for all plug-in power supply units): Plug-in power supply (Euro plug): Type no.: Z851 Order no.: 28 520 4897 FRIWO FW3288, 11.8134 Friwo Part No. 1816492 Input: 230V ~ / 50 Hz / 23 VA Output: 6 V = / 1,8 A /10,8 VA Plug-in power supply (US plug): Type no.: Z852 Order no.: 28 520 4901 FRIWO FW3288, 11.8451 Friwo Part No. 1816493 Input: 120V ~ / 60 Hz / 21,5 VA Output: 6 V = / 1,8 A Plug-in power supply (UK plug): Type no.: Z849 Order no.: 28 520 4975 FRIWO FW3288, 11.8453 Friwo Part No. 1770896 Input: 230V ~ / 50 Hz / 23 VA Output: 6 V = / 1,8 A

55

Overview

Connections

Electrodes

Socket according to DIN 19 262 or BNC 4 mm socket for reference electrode 4 mm socket for temperature probe 2-pole special Friwo

Temperature probe Plug-in power supply unit Input amplifier Input impedance Offset current

1012 10-12 A

Calibration modes

AutoCal TEC

With Technical buffers (given in pH): 2.00; 4.00; 7.00; 10.00 at 25 C; buffers are temperature compensated in the range 0 ... 90 C With standard buffers according to DIN 19 266/NIST (given in pH): 1.68; 4.01; 6.87; 9.18 at 25 C; buffers are temperature compensated in the range 0 ... 90 C With any buffers; single-point and two-point calibration, manual acceptance of measured values and temperature input

AutoCal DIN

ConCal

56

Safety

Safety

This operating manual contains basic instructions that you must follow during the commissioning, operation and maintenance of the pH meter. Consequently, all responsible personnel must read this operating manual before working with the instrument. The operating manual must always be available within the vicinity of the instrument. Target group This measuring instrument was developed for use in the laboratory. Thus, we assume that, as a result of their professional training and experience, the operators will know the necessary safety precautions to take when handling chemicals.

Symbols used

Caution indicates instructions that have to be followed to prevent damage to your instrument.

Warning indicates instructions that have to be followed to protect yourself and the instrument from dangerous electrical voltage.

Note Indicates notes that draw your attention to special features.

Note Indicates cross-references to other documents, e.g. application reports, operating manuals of combination electrodes, etc.

57

Safety

2.1

Authorized use

This instrument is authorized exclusively for pH and Redox measurements in the laboratory. The technical specifications as given in the chapter, TECHNICAL DATA, must be observed. Only the operation and running of the measuring instrument according to the instructions given in this operating manual is authorized. Any other use is considered unauthorized.

2.2

General safety instructions

This instrument is constructed and tested in compliance with the EN 61010-1 safety regulations for electronic measuring instruments. It left the factory in a safe and secure technical condition. Function and operational safety The smooth functioning and operational safety of the instrument can only be guaranteed if the generally applicable safety measures and the specific safety instructions in this operating manual are followed. The smooth functioning and operational safety of the instrument can only be guaranteed under the climatic conditions specified in the chapter 1.5 TECHNICAL DATA. If the instrument was transported from a cold environment to a warm environment, the formation of condensate can lead to the faulty functioning of the instrument. In this event, wait until the temperature of the instrument reaches room temperature before putting the instrument back into operation. Caution The instrument is only allowed to be opened by personnel authorized by SCHOTT.

58

Safety

Safe operation

If safe operation is no longer possible, the instrument must be taken out of service and secured against inadvertent operation. Safe operation is no longer possible if:
l l l l

the instrument has been damaged in transport the instrument has been stored under adverse conditions for a lengthy period of time the instrument is visibly damaged the instrument no longer operates as described in this manual

If you are in doubt contact the supplier of the instrument.

Obligations of the operator

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

EEC directives for protective labor legislation National protective labor legislation Safety regulations Safety datasheets of the chemical manufacturer.

59

Safety

60

Commissioning

3
l l l

Commissioning
Set the C or F Set the resolution Connect the plug-in power supply (optional).

Perform the following activities for the initial commissioning:

Setting C or F

The temperature can be displayed in C or in F . In the delivery condition, the measuring instrument is preset to C. To change the unit proceed as follows: 1 Switch the measuring instrument off. 2 Press and hold down the <pH> key. 3 Press the <on/off> key.

4 Toggle between C and F by pressing <v> <w>. 5 Confirm with <run/enter>. The measuring instrument switches to the measuring mode. Setting the resolution

1 Press and hold down the <run/enter> key. 2 Press the <pH> key. The measured values are displayed with a high resolution, e. g. pH = 4.012.

61

Commissioning

3 Press the <run/enter> and <pH> keys again. The measured values are displayed with a low resolution, e. g. pH = 4.01.

Connecting the plug-in power supply (optional)

The measuring instrument works battery-powered. It can, however, also be supplied by the plug-in power supply which is available as an accessory.

Warning The line voltage on site must lie within the input voltage range of the original plug-in power supply unit (see section 1.5 TECHNICAL DATA). Caution Use original plug-in power supplies only (see section 1.5 TECHNICAL DATA).

2 1

1 Insert the plug (1) into the socket (2) of the pH meter. 2 Connect the original plug-in power supply (3) to an easily accessible mains socket.

62

Operation

4
4.1

Operation
Switch on the instrument

1 Place the instrument on a flat surface and protect it against intense light and heat. 2 Press the <on/off> key. The display test appears briefly on the display. The instrument then switches automatically to the previously selected measuring mode. 3 Connect the pH electrode to the instrument. The measuring instrument is ready for operation.

Note The instrument has an energy saving feature to avoid unnecessary battery depletion. The energy saving feature switches the instrument off if no key has been pressed for an hour. The energy saving feature is not active if the instrument is supplied by the plug-in power supply.

63

Operation

4.2
Preparatory activities

Measuring

Perform the following activities when you want to measure: 1 Connect the pH electrode to the instrument. 2 Adjust the temperature of the buffer or test solutions or measure the current temperature if the measurement is made without a temperature probe. 3 Calibrate or check the instrument with the pH electrode according to section 4.3. 4 Select the measuring mode by pressing <pH>. Note Incorrect calibration of the pH electrode will result in incorrect measured values. Therefore, regularly perform calibration before measuring.

Temperature probe

Measurements can be performed with and without a temperature probe. A connected temperature probe is indicated by TP on the display. Note The pH meter automatically recognizes the type of the temperature probe used. As a result, you can connect electrodes with the NTC30 or Pt1000. The temperature measurement is absolutely essential for a reproducible pH measurement. If the measurement is made without a temperature probe, proceed as follows: 1 Determine the current temperature using a thermometer. 2 Set up the temperature by pressing <v> <w>. Note When calibrating without a temperature probe, set up the current temperature of the respective buffer solution manually by pressing the <v> <w> keys.

64

Operation

4.2.1 Measuring the pH value 1 Perform the preparatory activities according to section 4.2. 2 Immerse the pH electrode into the test sample. 3 Press the <pH> key until pH appears in the status display. The pH value appears on the display.

AutoRead AR (Drift control)

The AutoRead function (drift control) checks the stability of the measurement signal. The stability has a considerable effect on the reproducibility of the measured values. For identical measurement conditions, the following criteria apply: l pH value: better than 0.02 (setting time: > 30 s) 1 Call up the pH measuring mode by pressing <pH>. 2 Activate the AutoRead function by pressing <auto read>. The current measured value is frozen (Hold function). 3 Start the AutoRead function by pressing <run/enter>. AR flashes on the display until a stable measured value is reached. 4 If necessary, start the next AutoRead measurement by pressing <run/enter>. 5 To terminate the AutoRead function: Press the <auto read> key.

65

Operation

Note The current AutoRead measurement (with acceptance of the current value) can be terminated at any time by pressing <run/enter>.

4.2.2 Measuring the Redox voltage The pH meter can measure the Redox voltage (mV) of a solution when connected with a Redox electrode, e.g. BlueLine 31 Rx. 1 Perform the preparatory activities according to section 4.2. 2 Immerse the Redox electrode into the test sample. 3 Press the <pH> key repeatedly until U appears in the status line. The Redox voltage (mV) of the sample appears on the display. 4 Wait for a stable measured value.

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

66

Operation

4.3
Why calibrate?

Calibrating

pH electrodes age. This changes the asymmetry (zero point) and slope of the pH electrode. As a result, an inexact measured value is displayed. Calibration determines the current values of the asymmetry and slope of the electrode and they are stored in the instrument. Thus, you should calibrate at regular intervals. Note Always calibrate after connecting another electrode.

You can choose between 3 calibration procedures: AutoCal TEC is specially adapted to the Technical Buffer Solutions as a fully automatic two-point calibration. The buffer solutions are automatically recognized by the instrument. The following values are available: 2.00; 4.00; 7.00; 10.00. is specially adapted to permanently programmed buffer solutions according to DIN 19266 as a fully automatic twopoint calibration. The buffer solutions are automatically recognized by the instrument. The following values are available: 1.68; 4.01; 6.87; 9.18. is the conventional two-point calibration with 2 freely selectable buffer solutions or single-point calibration as the rapid method.

AutoCal DIN

ConCal

AutoRead

In calibration using AutoCal TEC and AutoCal DIN, the AutoRead function is automatically activated. The current AutoRead measurement (with acceptance of the current value) can be terminated at any time by pressing <run/enter>.

67

Operation

Calibration evaluation

After the calibration, the instrument automatically evaluates the current status. The asymmetry and slope are separately evaluated. The worst evaluation appears on the display. Display Asymmetry [mV] -15 ... +15 Slope [mV/pH] 58 ... 60.5

-20 ... +20

57 ... 58

-25 ... +25

56 ... 57 or 60.5 ... 61 56 ... 50 or 61 ... 62

-30 ... +30

Clean the electrode according to the electrode operating manual

Clear the fault according to chapter 6 WHAT TO DO IF...

< -30 or > 30

< 50 or > 62

Preparatory activities

1 Switch on the instrument by pressing <on/off>. 2 Connect the pH electrode to the instrument. 3 Keep the buffer solutions ready. 4 Adjust the temperature of the solutions and measure the current temperature if the measurement is performed without a temperature probe.

68

Operation

4.3.1 AutoCal TEC Use any two of the Technical Buffer Solutions for this procedure. Note Steps 2 and 6 are not required if you use a temperature probe.

1 Press the <CAL> key repeatedly until Ct1 and the AutoCal TEC function display appear.

2 If necessary, set the temperature of the buffer solution by pressing <v> <w> . 3 Submerse the pH electrode in the first buffer solution. 4 Press the <run/enter> key. AR flashes on the display. The electrode voltage (mV) appears on the display. As soon as a stable value is recognized, Ct2 appears.

5 Thoroughly rinse the electrode with distilled water.

69

Operation

6 If necessary, set the temperature of the second buffer solution by pressing <v> <w>. 7 Submerse the electrode in the second buffer solution. 8 Press the <run/enter> key. AR flashes on the display. The electrode voltage (mV) appears on the display. As soon as a stable value is recognized, AR disappears. The sensor symbol shows the electrode evaluation after the two-point calibration. The value of the slope (mV/pH) appears on the display. 9 Press the <run/enter> key. The value of the asymmetry (mV) appears on the display. 10 To return to the measuring mode: Press the <pH> key.

70

Operation

4.3.2 AutoCal DIN Use two different DIN buffer solutions for this procedure: DIN buffer solution A C D F pH 1.68 4.01 6.87 9.18

Note Steps 2 and 6 are not required if you use a temperature probe.

1 Press the <CAL> key repeatedly until Cd1 and the AutoCal DIN function display appear.

2 If necessary, set the temperature of the buffer solution by pressing <v> <w>. 3 Submerse the pH electrode in the first buffer solution. 4 Press the <run/enter> key. AR flashes on the display. The electrode voltage (mV) appears on the display. As soon as a stable value is recognized, Cd2 appears.

71

Operation

5 Thoroughly rinse the electrode with distilled water. 6 If necessary, set the temperature of the second buffer solution by pressing <v> <w>. 7 Submerse the electrode in the second buffer solution. 8 Press the <run/enter> key. AR flashes on the display. The electrode voltage (mV) appears on the display. As soon as a stable value is recognized, AR disappears. The sensor symbol shows the electrode evaluation after the two-point calibration. The value of the slope (mV/pH) appears on the display. 9 Press the <run/enter> key. The value of the asymmetry (mV) appears on the display. 10 To return to the measuring mode: Press the <pH> key.

72

Operation

4.3.3 ConCal Two-point calibration Use two buffer solutions for this procedure:
l l

pH 7.0 0.5 any other buffer solution

Note Steps 2 and 9 are not required if you use a temperature probe.

1 Press the <CAL> key repeatedly until ASY and the ConCal function display appear.

2 If necessary, set the temperature of the buffer solution by pressing <v> <w>. 3 Submerse the pH electrode in the pH 7.0 0.5 buffer solution. 4 Press the <run/enter> key. The measured pH value appears on the display. 5 Set the nominal pH value of the buffer solution (at the current temperature) by pressing the <v> <w> keys. 6 Press the <run/enter> key. The value of the asymmetry (mV) and the sensor symbol appear on the display. 7 Press the <run/enter> key. SLO(pe) appears on the display.

73

Operation

8 Thoroughly rinse the electrode with distilled water. 9 If necessary, set the temperature of the second buffer solution by pressing <v> <w>. 10 Submerse the electrode in the second buffer solution. 11 Press the <run/enter> key. The second measured pH value appears on the display. 12 Set the nominal pH value of the second buffer solution (at the current temperature). 13 Press the <run/enter> key. The value of the slope (mV/pH) appears on the display. The sensor symbol shows the evaluation of the electrode after the two-point calibration. 14 Press the <run/enter> key. The value of the asymmetry (mV) appears on the display again. 15 To return to the measuring mode: Press the <pH> key.

74

Operation

Single-point calibration

Use a buffer solution in the range pH = 7.0 0.5 for this procedure. Note Only the electrode asymmetry is determined in single-point calibration. The slope of the last two-point calibration is retained. Note Step 2 is not required if you use a temperature probe. The TP display indicates an active temperature measurement.

1 Press the <CAL> key repeatedly until ASY and the ConCal function display appear.

2 Set the temperature of the buffer solution by pressing <v> <w>. 3 Submerse the pH electrode in the buffer solution. 4 Press the <run/enter> key. The measured pH value appears on the display. 5 Set the nominal pH value of the buffer solution (at the current temperature) by pressing the <v> <w> keys. 6 Press the <run/enter> key. The value of the asymmetry (mV) and the sensor symbol for the evaluation of the electrode appears on the display. 7 To return to the measuring mode: Press the <pH> key.

75

Operation

4.4
Basic settings

Reset

The following functions are reset (initialized) to the values they had on delivery: Measuring mode Asymmetry Slope Calibration procedure Temperature, manual Resolution of pH display Proceed as follows: 1 Press and hold down the <run/enter> key. 2 Press the <CAL> key. pH 0 mV -59.16 mV/pH AutoCal TEC 25C 0,01

3 Toggle between no and yes by pressing <v> <w>. yes: reset parameters. no: retain settings. 4 Confirm with <run/enter>. The pH meter changes automatically to the pH measuring mode.

76

Maintenance, cleaning, disposal

5
5.1

Maintenance, cleaning, disposal

The measuring instrument is almost maintenance-free. The only maintenance task is replacing the batteries: 1 Open the battery compartment (1) on the underside of the instrument. 2 Remove the four batteries from the battery compartment. 3 Insert four new batteries (Type Mignon AA) into the battery compartment. 4 Close the battery compartment (1).

Caution Make sure that the poles of the batteries are the right way round. The signs in the battery compartment must correspond to the signs on the batteries. Only use leakproof alkaline manganese batteries. Note See the relevant operating manual of the electrode for instructions on maintenance.

77

Maintenance, cleaning, disposal

5.2

Cleaning

Occasionally wipe the outside of the measuring instrument with a damp, lint-free cloth. Disinfect the housing with isopropanol as required. Caution The housing is made of synthetic material (ABS). Thus, avoid contact with acetone or similar detergents that contain solvents. Remove any splashes immediately.

5.3
Packing

Disposal

The measuring instrument is sent out in a protective transport packing. We recommend: Keep the packing material. The original packing protects the instrument against damage during transport.

Batteries

This note refers to the battery regulation that applies in the Federal Republic of Germany. We would ask end-consumers in other countries to follow their local statutory provisions. Note In compliance with 14 of the BATTERY REGULATION, we would like to point out that this instrument contains batteries. Batteries that have been removed must only be disposed of at the recycling facility set up for this purpose or via the retail outlet. It is illegal to dispose of them in household refuse.

Measuring instrument

Dispose of the measuring instrument as electronic waste at an appropriate collection point. It is illegal to dispose of them in household refuse.

78

What to do if...

6
Error message, I /

What to do if...
Remedy

Cause pH electrode: Not connected Air bubbles in front of the diaphragm Air in the diaphragm Cable broken Gel electrolyte dried out

Connect electrode Remove air bubbles Extract air or moisten diaphragm Replace electrode Replace electrode

Error message, 

Cause pH electrode: Diaphragm contaminated Membrane contaminated Moisture in the plug Electrolyte obsolete Electrode obsolete Electrode broken Measuring instrument: Incorrect calibration procedure Incorrect solution temperature (without temperature probe) Socket damp

Remedy

Clean diaphragm Clean membrane Dry plug Replenish electrolyte or replace electrode Replace electrode Replace electrode

Select correct procedure Set up correct temperature Dry socket

79

What to do if...

Buffer solutions: Incorrect buffer solutions Buffer solutions too old Buffer solutions depleted Change calibration procedure Only use once. Note the shelf life Change solutions

No stable measured value

Cause pH electrode: Diaphragm contaminated Membrane contaminated Sample: pH value not stable Temperature not stable

Remedy

Clean diaphragm Clean membrane

Measure with air excluded if necessary Adjust temperature if necessary

Electrode + sample: Conductivity too low Temperature too high Organic liquids Use suitable electrode Use suitable electrode Use suitable electrode

Cause LoBat Batteries almost depleted

Remedy Replace batteries (see section 5.1 MAINTENANCE)

80

What to do if...

Obviously incorrect measured values

Cause pH electrode unsuitable Temperature difference between buffer and sample too large Measuring procedure not suitable

Remedy Use suitable electrode Adjust temperature of buffers or samples Follow special procedure

Instrument does not react to keystroke

Cause Operating state undefined or EMC electric stress unallowed

Remedy Processor reset: Press the <auto read> key and switch on the instrument

81

What to do if...

82

Lists

Lists

This chapter provides additional information and orientation aids.

Abbreviations

The list of abbreviations explains abbreviations that appear on the display or when dealing with the instrument.

Specialist terms

The glossary briefly explains the meaning of the specialist terms. However, terms that should already be familiar to the target group are not described here.

Index

The index helps you find the topics that you are looking for.

83

Lists

Abbreviations AR ARng AutoRead (drift control) Automatic range switching Measuring instrument measures with highest resolution Asymmetry Automatic calibration with DIN buffer solutions Automatic calibration with Technical Buffer Solutions Calibration Calibration with DIN buffer solutions (acc. to DIN 19 266) Conventional one/two point calibration Calibration with Technical Buffer Solutions Error message (see WHAT TO DO IF ...) Initialization Resets individual basic functions to the status they had on delivery Low Battery Batteries are almost empty Voltage unit Unit of the electrode slope Overflow Display range exceeded pH value Slope Safety Extra Low Voltage Slope Slope setting on calibration

ASY AutoCal DIN AutoCal TEC Cal Cd... ConCal Ct... E3 InI

LoBat mV mV/pH OFL pH S SELV SLO

84

Lists

TP UASY C F

Temperature probe Temperature measurement active Asymmetry potential Temperature unit, Celsius Temperature unit, Fahrenheit

85

Lists

Glossary

Asymmetry

Zero point of a pH electrode.

Resolution

Number of decimal places that appear for a measured value. Monitors the electrode drift and releases the measured value only after the stability criterion has been reached. In this way, this procedure ensures the highest degree of precision and reproducibility. Contact point between the reference electrolytic solution and the sample. See AUTOREAD.

AutoRead

Diaphragm

Drift control

Test solution

Stable solution with a precisely known Redox voltage.

Buffer solution

Stable solution with a precisely known pH value.

Redox voltage

Potentiometric quantity.

Slope

Specifies the voltage change per pH unit.

86

Lists

Index

A
asymmetry 67 authorized use 58 AutoCal DIN 67, 71 AutoCal TEC 67, 69 AutoRead 65

P
place of the instrument 63 plug-in power supply 62 power supply 54, 62

R
Redox electrode 66 Redox voltage 66 replacing the batteries 77 reset 76

B
basic settings 76 battery compartment 77 Buchsenfeld 51

S C
calibrating 67 calibration evaluation 68 calibration procedures 67 ConCal 67, 73 safety 57 safety precautions 57 setting the resolution 61 setting the temperature unit 61 single-point calibration 67 ConCal 75 slope 67

D
delivery condition 76 display 51 drift control 65

T
temperature probe 64 two-point calibration 67 AutoCal DIN 72 AutoCal TEC 70 ConCal 73

E
energy saving feature 63 error messages 79

I
initialize 76

K
keys 50

L
LoBat 80

O
operational safety 58

87