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4  Calibrating a pH combination electrode 

20

4.5

Display of the electrode state

✱

Briefly press the 

 key.

The state of the pH combination electrode will be displayed for approx. 3 
seconds.

4.6

Parameters in the combination electrode display

Show 
asymmetry

✱

Briefly press the 

 key.

The state of the pH combination electrode will be displayed for approx. 3
seconds after every calibration.

100%

The combination electrode is in very good condition

90 — 30%

The state of the combination electrode is satisfactory

less than 
30%

The combination electrode is severely aged or contaminated.

If there is no improvement after cleaning (see Chapter 7.2
“Cleaning”, page 27) and a subsequent calibration, then the
combination electrode must be replaced.

2

CAL

3

pH

mV

mV

H

rH

ATC

ok

CAL

AL Logg

pH

mbar

The evaluation takes into account both the asymmetry and the slope of the
combination electrode.

Permissible 
range

±60 mV

Optimum

0 mV

2

CAL

3

pH

mV

mV

H

rH

ATC

ok

CAL

AL Logg

pH

mbar

Asymmetry -30 mV

Contamination can seriously worsen the asymmetry of the combination
electrode.

Summary of Contents for 202710

Page 1: ...Hand held Meter for analytical measurement variables pH redox temperature Type 202710 and Type 202720 B 20 2710 0 Operating Instructions 2010 11 08 00461261 ...

Page 2: ......

Page 3: ...4 Set temperature offset 11 3 5 Set automatic power off 12 3 6 Adr 12 3 7 Manual temperature setting for operation without a temperature sensor 13 3 8 Manual pH setting for the rH measurement function 13 4 Calibrating a pH combination electrode 15 4 1 Preparation 15 4 2 Start 16 4 3 With a temperature sensor 17 4 4 Without temperature sensor 18 4 5 Display of the electrode state 20 4 6 Parameters ...

Page 4: ...ination electrode 26 7 1 pH combination electrodes for various application areas 26 7 2 Cleaning 27 7 3 Operating life 27 7 4 General handling of pH combination electrodes 27 8 The redox combination electrode 29 8 1 General handling 29 9 Technical data 30 ...

Page 5: ...d or not followed correctly Note This symbol is used when your special attention is drawn to a remark abc1 Footnote Footnotes are remarks that refer to specific points in the text Footnotes consist of two parts A marker in the text and the footnote text The markers in the text are arranged as continuous superscript numbers Action instruction This symbol indicates that an action to be performed is ...

Page 6: ...t in safety or emergency stop installations or in applications where a malfunction of the device could lead to injury to personnel or significant material damage Please do not attach any equipment to socket 20 see Chapter 2 5 Connections page 9 Correct functioning and operational reliability of the instrument will only be assured when the permissible climatic conditions are observed see Chapter 9 ...

Page 7: ...ecalibration 5 ATC arrow in the operating modes pH mVH or rH this indicates that the temperature sensor is connected and the automatic temperature compensation is active 6 OK arrow this indicates that the measurement was stable for a sufficiently long time 7 CAL arrow in pH operation this indicates that the instrument is in calibration mode 8 Subsidiary display Temperature measurement or operator ...

Page 8: ...ode condition and calibration data press for 2 seconds starts the pH calibration 13 Set Menu press briefly Set for pH rH and mVH manual temperature entry if no temperature probe is connected Additionally for rH manual entry of the pH value press for 2 seconds set the operating mode Menu call up the configuration 14 Store Quit During measurement hold and store the present measurement The display sh...

Page 9: ... socket has no function Please do not connect any equipment here 21 BNC socket Connection for pH or redox combination electrode 22 Mini DIN socket Connection for a Pt100 temperature sensor 4 wire connection A 2 wire connection is possible but there will be an additional measurement error depending on the lead length 20 21 22 ...

Page 10: ...h a pH combination electrode mV Redox measurement with a redox combination electrode mVH As for mV The indicated value is converted to the standard hydrogen system temperature independent DIN 38 404 This requires the connection of the temperature sensor ATC or a manual temperature entry rH The rH value is calculated from the measured pH redox and temperature values The pH and temperature values ca...

Page 11: ...oint calibration The calibration of the pH combination electrode is carried out for two points one point in the neutral range and one point in the acidic or alkaline range 3 Pt 3 point calibration The calibration of the pH combination electrode is carried out for three points one point in the neutral range and one point each in the acidic and alkaline ranges max 2 min 5 pH mV mVH rH ATC ok CAL AL ...

Page 12: ...his amount to compensate for probe or measurement deviations Measured temperature minus offset displayed temperature Off The zero point shift is switched off 0 0 max 2 min 5 C pH mV mVH rH ATC ok CAL AL Logg pH max min 2 5 1 120 Automatic power off delay in minutes If no key is pressed on the hand held meter it will switch off after this time has elapsed Off Continuous operation appropriate when f...

Page 13: ...he or key to set the temperature for the measured medium Confirm the entry with the key 3 8 Manual pH setting for the rH measurement function For exact measurement of rH the hand held meter must know the temperature and pH of the medium being measured The hand held meter can also measure the rH value for a liquid when the temperature and pH values are entered manually Start configuration Select th...

Page 14: ...et the pH value Confirm the entry with the key The hand held meter now switches back to measurement mode 0 00 14 00 Setting range for manual entry of the pH value max 2 min 5 max min 2 5 pH mV mVH rH ATC ok CAL AL Logg pH mbar Store Quit 6 ...

Page 15: ... electrode the protective cap contains 3 mol KCl Rinse the combination electrode and the temperature sensor if present with de ionized distilled water and dry off Buffer solutions have a limited usable life that is for instance seriously reduced by inadequate rinsing and drying of the combination electrode when changing solutions This can lead to calibration errors Use the freshest possible soluti...

Page 16: ...ong press on the key is used to switch between various buffer series Buffer solutions can be obtained from laboratory suppliers 2 CAL 3 Values at 25 C 4 00 pH 7 00 pH pH mV mVH rH ATC ok CAL AL Logg pH mbar neutral calibration solution 7 00 pH Values at 25 C 01 68 pH A 04 01 pH C 06 87 pH D 09 18 pH F 12 45 pH G pH mV mVH rH ATC ok CAL AL Logg pH mbar neutral calibration solution 6 87 pH Input ran...

Page 17: ...will be displayed see Chapter 4 5 Display of the electrode state page 20 Rinsing Rinse the combination electrode and the temperature sensor with de ionized distilled water and dry off Calibration point 3 only for 3 point calibration Immerse the combination electrode and the temperature sensor in the third buffer solution Buffers from the standard or DIN series will automatically be detected Enter ...

Page 18: ...ill request that you enter a temperature Enter the present temperature of buffer 1 with the or key Press the key to accept the measurement Rinsing Rinse the combination electrode with de ionized distilled water and dry off Calibration point 2 Immerse the combination electrode in the second buffer solution and stir When the display has stopped blinking and the OK arrow appears at bottom left the me...

Page 19: ... will automatically be detected When the display has stopped blinking and the OK arrow appears at bottom left the measurement is stable Press the key to accept the measurement The hand held meter will request that you enter a temperature Enter the present temperature of buffer 3 with the or key Press the key to accept the measurement Rinsing Rinse the combination electrode with de ionized distille...

Page 20: ...od condition 90 30 The state of the combination electrode is satisfactory less than 30 The combination electrode is severely aged or contaminated If there is no improvement after cleaning see Chapter 7 2 Cleaning page 27 and a subsequent calibration then the combination electrode must be replaced 2 CAL 3 pH mV mVH rH ATC ok CAL AL Logg pH mbar The evaluation takes into account both the asymmetry a...

Page 21: ...um 59 2 mV pH 2 CAL 3 pH mV mVH rH ATC ok CAL AL Logg pH mbar Slope 52 9 mV pH After the 2 point calibration the slope SL for the entire range will be shown After the 3 point calibration the slope shown first is that for the acidic range SL 1 If you press the CAL key again the slope shown will be that for the alkaline range SL 2 ...

Page 22: ... held meter Configure the hand held meter for rH measurement see Chapter 3 1 Select measurement function pH redox mV redox mVH rH thEr page 10 The main display will show the rH value that has been determined The subsidiary display will alternately show the previously measured pH and the temperature For this measurement special care should be taken that both the pH and redox combination electrodes ...

Page 23: ...nter the temperature Briefly press the key Use the or key to enter the pH value Briefly press the key The main display will show the rH value that has been determined The subsidiary display will alternately show the previously measured pH and the temperature The measurements for temperature and pH can also be manually entered in the hand held meter Set Menu 4 max 2 min 5 Set Menu 4 max 2 min 5 Sto...

Page 24: ...hand held meter is faulty Gone beyond the measurement range Defect in combination electrode temperature sensor or connecting cable Check combination electrode temperature sensor and connecting cable and replace if necessary Gone below measurement range Defect in combination electrode temperature sensor or cable Check combination electrode temperature sensor and connecting cable and replace if nece...

Page 25: ...n the combination electrode Repeat calibration Replace the combination electrode Always use the neutral buffer as the first solution Use fresh buffer solution The slope is too flat combination electrode is faulty buffer solution is exhausted Replace the combination electrode Use fresh buffer solution The slope is too steep combination electrode is faulty buffer solution is exhausted Replace the co...

Page 26: ...bjected to chemical and mechanical wear and must therefore be replaced when the required parameters can no longer be upheld even after meticulous cleaning When using them it must be taken into account that some substances in aqueous solutions e g hydrofluoric acid HF can attack glass Chemicals may also react with the KCl electrolyte in the combination electrode and or lead to the diaphragm becomin...

Page 27: ...re in a dry room at a temperature between 10 C and 30 C Below 0 C the combination electrode can be destroyed by freezing of the electrolyte The sensor portion of the combination electrode should be protected against drying out by using a protective cap filled with 3 mol KCl solution or a storage holder Lengthy storage in de ionized distilled water will result in a depletion of the KCl within the c...

Page 28: ...he measuring function of the electrode is impaired for instance the display is very sluggish check the combination electrode for air bubbles check the function with a second reference combination electrode replace the combination electrode Solutions for calibration cleaning and activation can be obtained from JUMO or from laboratory suppliers ...

Page 29: ...a pepsin hydrochloric acid solution Sales No 20 00307114 is recommended The platinum tip of the sensor can be cleaned with ordinary scouring powder rinse well afterwards If there is a malfunction of the combination electrode check the function with a second reference combination electrode replace the combination electrode Solutions for calibration cleaning and activation can be obtained from JUMO ...

Page 30: ... for 4 wire Pt100 can also be connected as 2 wire Input resistance pH redox 1012 Ohm Nominal temperature 25 C Working temperature 0 to 50 C Relative humidity 0 95 r h no condensation Storage temperature 20 to 70 C Memory Min value Max value Hold memory Electrical supply 9 V battery type IEC 6F22 included in delivery Power input socket inner pin 1 9 mm dia pole for external supply 10 5 12 V DC use ...

Page 31: ... temperature dependency is automatically compensated Manual buffers can be used Permissible electrode data asymmetry 60 mV slope 62 to 45 mV pH Sensor weighting 10 to 100 according to the calibration results Recommended redox combination electrodes Reference system Ag AgCl electrolyte KCl 3 mol liter JUMO ecoLine Rd 2 m fixed connecting cable and BNC connector Type 201010 54 22 65 2000 76 120 000 ...

Page 32: ......

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