wtw VARIO Operating Manual
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wtw VARIO Operating Manual

Hand-held ph meter
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Operating manual
VARIO pH
Hand-held pH meter
ba75373e03
05/2005

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  • Page 1 Operating manual VARIO pH Hand-held pH meter ba75373e03 05/2005...
  • Page 2 Therefore, we are sure you will understand that we cannot accept any legal claims resulting from the data, figures or descriptions. © Copyright 2005, WTW GmbH Reprinting - even as excerpts - is only allowed with the explicit written authorization of WTW GmbH, Weilheim. Printed in Germany. ba75373e03 05/2005...

  • Page 3: Table Of Contents

    VARIO pH Overview ........5 Safety .
  • Page 4 VARIO pH What to do if........43 Technical data ....... . 47 General data .

  • Page 5: Overview

    VARIO pH Overview Overview The hand-held VARIO pH meter enables you to measure the pH value of a solution very simply. All functions and settings are operated via the touch screen. Display (touch screen) Connector (red) for a temperature sensor when using an electrode...
  • Page 6 Overview VARIO pH Note Certain sensors enhance the scope of functions of the VARIO pH. More detailed information on the presently available sensors and their individual features can be found in chapter 7 T ECHNICAL DATA Note You will find additional information on electrodes and other accessories in the WTW catalog or on the Internet (http://www.wtw.com).

  • Page 7: Safety

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

  • Page 8: General Safety Instructions

    Safety VARIO pH General safety instructions This instrument is built and inspected according to the relevant guidelines and norms for electronic measuring instruments (see chapter 7 T ECHNICAL DATA It left the factory in a safe and secure technical condition.

  • Page 9: Commissioning

    VARIO pH Commissioning Commissioning Scope of delivery ! VARIO pH hand-held meter VARIO pH single meter ! WTW Technical buffers – pH 4.01 – pH 7.00 ! Short pH electrode with transport cap ! Watering cap ! Microfiber cleaning cloth ! Accompanying documents: –...

  • Page 10: Initial Commissioning

    Commissioning VARIO pH Initial commissioning Perform the following activities: ! Connect the electrode to the meter (see section 3.3 and section 3.4) ! If necessary, connect the temperature sensor (see section 3.4) ! Switch on the meter (see section 4.2) ! Set the date and time (see section 4.6.1)
  • Page 11 VARIO pH Commissioning Place the short pH electrode in a straight position to the meter (turn the wide cut-out to the front) and plug it in carefully with slight force. Screw the short pH electrode tight using the coupling ring.

  • Page 12: Connecting An Electrode

    With an electrode without integrated temperature sensor, you can additionally connect an external NTC 30 temperature probe. 3.4.1 Electrode with integrated temperature sensor Connect an electrode with integrated temperature sensor to the VARIO pH as follows: Unscrew the coupling ring (1) from the meter.
  • Page 13 VARIO pH Commissioning VARIO pH with connected electrode DIN adapter Plug of the NTC 30 temperature sensor RESET 7 9 4 2 4 8 LoBat Day.Month h:min min:s Ident Electrode ba75373e03 05/2005...

  • Page 14: Electrode Without Temperature Sensor

    Connect the adapter to the meter (see section 3.4.1). Connect the plug of the electrode to the adapter. If necessary, connect the two banana plugs of the external temperature probe to the lateral sockets on the VARIO pH. The polarity is arbitrary. VARIO pH with...

  • Page 15: Electrode With S7 Connector

    Ident S7 Adaptor plug head of electrode Connection with Depending on the electrode used, it is connected to the VARIO pH via a cable cable as described in section 3.4.1 or section 3.4.2. Note When using an electrode without temperature sensor it is possible to connect an external temperature probe (see section 3.4.4).

  • Page 16: Connecting An External Temperature Probe

    When using an electrode without temperature sensor it is possible to connect an external temperature probe. Connect an external temperature probe as follows: Connect the two banana plugs of the external temperature probe to the lateral sockets on the VARIO pH. The polarity is arbitrary. VARIO pH with connected electrode and...

  • Page 17: Operation

    VARIO pH Operation Operation Operating elements The entire operation is carried out via the touch sensitive surface of the display (touch screen). A slight pressure on the surface suffices to start a function. Any pressure on the surface is confirmed by an acoustic signal.
  • Page 18 Operation VARIO pH Touch screen In this operating manual, keys are indicated by angle brackets <..>. operation The touch screen symbol (example <3>) shows you which area you have to press. Function keys are indicated by the relevant name or symbol.

  • Page 19: Switching On The Meter

    Depth of Instructions on the depth of immersion of electrodes that are run on the immersion of VARIO pH via the adapter can be found in the documentation of your electrodes electrode. AutoRead The AutoRead function (drift control) checks the stability of the measurement (drift control) signal.

  • Page 20: Measuring The Ph Value

    Operation VARIO pH 4.3.2 Measuring the pH value Make sure the measuring system has a valid calibration (see section 4.4). Immerse the electrode in the test sample. The display shows the main measured value (pH or mV) and temperature value. When operating an electrode without temperature sensor on the adapter, the manually entered temperature value is displayed (see section 4.3.3).
  • Page 21 VARIO pH Operation Note The meter automatically recognizes a temperature sensor. The display accuracy of the temperature indicates whether or not a temperature sensor is connected: Display accuracy of Temperature sensor the temperature (°C or °F) connected? Changing the You can switch the temperature display from °C to °F: temperature unit Toggle the display between °C and °F with <§_>...

  • Page 22: Calibration

    Operation VARIO pH Calibration Why calibrate? pH electrodes age. This changes the asymmetry (zero point) and slope of the pH electrode. As a result, an inexact measured value is displayed. Calibration determines the current values of the asymmetry and slope of the electrode.
  • Page 23 VARIO pH Operation Determined values Displayed calibration data ! Asymmetry = ASY 1-point ! Slope = Nernst slope (59.2 mV/pH at 25 °C) ! Asymmetry = ASY 2-point ! Slope = SLO ! Asymmetry = ASY 3-point ! Slope = SLO The calibration line is calculated by linear regression.

  • Page 24: Carrying Out Calibration

    Operation VARIO pH 4.4.1 Carrying out calibration Preparatory activities Switch on the meter with <(>. After the display test, a measured value is displayed. Keep buffer solutions from a TEC or Nist/DIN buffer set ready. For this purpose: Fill a sufficient quantity of each buffer solution in a small beaker.
  • Page 25 VARIO pH Operation Start measurement with <g>. The unit of the measured value display flashes (AutoRead) as long as the measured value is not stable. Toggle between the display of the nominal buffer value (pH) and the electrode voltage (mV) as necessary with <"> [<pH or mV>].
  • Page 26 Operation VARIO pH Three-point To continue the calibration with a further buffer, thoroughly rinse the calibration electrode with deionized water. If necessary, enter the temperature of the third buffer solution manually. Immerse the pH electrode in the buffer solution. Start measurement with <g>.

  • Page 27: Displaying The Calibration Data

    VARIO pH Operation 4.4.2 Displaying the calibration data The calibration data are displayed after calibrating (see section 4.4.1) and are accessible at any time. Switch on the meter with <(>. The display test is displayed. During the display test: Display the date of the last calibration with <C>.

  • Page 28: Setting The Calibration Interval

    Operation VARIO pH 4.4.3 Setting the calibration interval The calibration interval determines how many days after the last calibration the instrument should remind you to recalibrate. The probe symbol on the display flashes when the calibration interval has expired. Using <C_>, start the INIT initialization menu.

  • Page 29: Saving

    VARIO pH Operation Saving The VARIO pH meter has a data memory. It can store up to 50 measurement datasets, depending on the short pH electrode or DIN adapter connected. A dataset consists of: ! Main measured value (pH measured value or mV measured value)

  • Page 30: Displaying Measured Data From The Memory

    Operation VARIO pH If all memory locations are occupied, the StoFull message appears. You have the following options: Saving the current measured value. Press <g> The oldest measured value (memory location 1) will be overwritten by this Returning to the measuring mode without saving Press <E>...

  • Page 31: Erasing Measured Data From The Memory

    VARIO pH Operation 4.5.3 Erasing measured data from the memory To erase all datasets proceed as follows: Display the memory with <M_>. The r status indicator appears on the display. The measured value that was saved last is displayed. Erase the entire memory with <D>.
  • Page 32 Operation VARIO pH Setting the date Switch on the meter with <(>. and time After a short display test, a measured value is displayed. Press <U> to indicate the time and date on the display. The U status indicator appears.

  • Page 33: Alarm Function

    VARIO pH Operation 4.6.2 Alarm function With the alarm function you set a point of time (alarm time) at which an alarm signal should sound. Prerequisite is the correct setting of the time (see section 4.6.1). The alarm signal also sounds when the meter is switched off.

  • Page 34: Stopwatch

    Operation VARIO pH Switching off the Display the alarm time (see above). alarm function Switch off the alarm function with <E>. The display shows the date and time. The alarm function is switched off. 4.6.3 Stopwatch With the stopwatch, you measure time periods of up to 59:59 (minutes:seconds).

  • Page 35: Timer

    VARIO pH Operation 4.6.4 Timer The timer function can count down the seconds of a specified time interval (timer interval) of maximum 59:59 (minutes:seconds). When the specified timer interval has expired, an alarm signal sounds for one minute and the display flashes.

  • Page 36: Switch-Off Interval

    Operation VARIO pH Switch-off interval The automatic switch-off switches off the meter automatically if no entry is made for a specified time (switch-off interval). This saves the battery of the meter. You can specify the switch-off interval yourself. The switch-off interval is from 10 minutes minimum to 24 hours maximum.

  • Page 37: Turning The Display

    VARIO pH Operation Turning the display When operating the meter with the adapter, the display indication can be turned by 180 degrees. Thus the cables of a connected electrode can be led backwards. Switch on the meter with <(>. After the display test, a measured value is displayed.

  • Page 38: Reset

    Operation VARIO pH Reset The following measurement parameters are reset to the delivery status: Parameter Default settings Measuring mode Asymmetry 0 mV Slope -59.2 mV/pH Calibration procedures Temperature, manual 25 °C Note The calibration data gets lost when the measurement parameters are reset.

  • Page 39: Maintenance, Cleaning, Disposal

    VARIO pH Maintenance, cleaning, disposal Maintenance, cleaning, disposal Maintenance The meter is almost maintenance-free. The only maintenance activity is exchanging the battery when it is depleted (LoBat display indicator). Battery exchange The LoBat display indicator indicates that the battery should be changed. The battery is then largely depleted.

  • Page 40: Cleaning

    Maintenance, cleaning, disposal VARIO pH Cleaning Occasionally wipe the outside of the meter with a damp, soft cloth. Caution The housing components are made out of synthetic materials (polyurethane, ABS and PMMA). Thus, avoid contact with acetone and similar detergents that contain solvents. Remove any splashes immediately.

  • Page 41: Storage

    VARIO pH Maintenance, cleaning, disposal Storage To maintain the operability of the meter and short pH electrode for a long time, please observe the following instructions: ! Do not store the short pH electrode for a longer period of time without the watering cap put on.

  • Page 42: Transport

    Maintenance, cleaning, disposal VARIO pH Transport Activate the cleaning mode. Thus, the instrument will not interpret any contact with the touch screen as an entry while being transported, e. g. in a pocket (see chapter 5.3). Disposal Dispose of the meter without the battery as electronic waste at an appropriate collection point.

  • Page 43: What To Do If

    VARIO pH What to do if... What to do if... Error message Cause Remedy 0FL, UFL – Air bubble in front of the junction – Remove air bubble – Electrode defective – Replace electrode Error message Cause Remedy Err3 Err3...
  • Page 44 What to do if... VARIO pH Error message Cause Remedy Err4 Err4 Err4 Err4 No short pH electrode or adapter – Connect short pH electrode or adapter – Check the plug connection – Switch the meter off and then on again.
  • Page 45 VARIO pH What to do if... Adapter with electrode + measuring solution: – Conductivity too low – Use suitable electrode – Temperature too high – Use suitable electrode – Organic liquids – Use suitable electrode Display of l Cause Remedy –...
  • Page 46 What to do if... VARIO pH ba75373e03 05/2005...

  • Page 47: Technical Data

    VARIO pH Technical data Technical data Depending on the connected sensor (short pH electrode or external electrode), the VARIO pH instrument has different functions or measuring features. General data Dimensions approx. 140 x 80 x 33 mm (without short pH electrode, without adapter) Weight approx.

  • Page 48: Measuring Ranges, Resolution, Accuracy

    Technical data VARIO pH Measuring ranges, resolution, accuracy 7.2.1 Short pH electrode SenTix V Measured Measuring Resolution Accuracy (± 1 digit) parameter range - 0.00 ... + 14.00 0,01 ± 0.01 * U [mV] - 1000 ... + 1000 ± 1 T [°C]...

  • Page 49: Lists

    VARIO pH Lists Lists This chapter provides additional information and orientation aids. Abbreviations The list of abbreviations explains the indicators and the abbreviations that appear on the display and in the manual. 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.
  • Page 50 Lists VARIO pH Abbreviations Asymmetry NIST pH calibration with buffer solutions produced according to DIN 19 266 pH calibration with WTW technical buffer solutions according to DIN 19267 °C Temperature unit, degrees Celsius Calibration Init Initialization Resets individual basic functions to the status they had...
  • Page 51 Designation for the offset potential of a pH electrode. The measurable potential of a symmetrical electrode, the membrane of which is immersed in a solution with the pH of the nominal electrode zero point. For WTW electrodes, the pH of the nominal electrode zero point is pH 7.
  • Page 52 Lists VARIO pH pH value The pH is a measure of the acidic or basic effect of an aqueous solution. It corresponds to the negative decadic logarithm of the molal hydrogen ions activity divided by the unit of the molality. The practical pH value is the value of a pH measurement.

  • Page 53: Index

    VARIO pH Index Index .........33 ............7 Alarm function Safety ..........22 ............ 29 Asymmetry Saving ...........7 ......29 Authorized use Saving measured data ........9 Scope of delivery ............. 22 Slope ..........34 Stopwatch ..........22 Calibration ........36 Switch-off interval ........27...
  • Page 54 Index VARIO pH...

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