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Metrohm 780 Manual

Ph meter / ph/ion meter
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780 pH Meter / 781 pH/Ion Meter
Manual
8.781.8002EN / 2014-07-31

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  • Page 1 780 pH Meter / 781 pH/Ion Meter Manual 8.781.8002EN / 2014-07-31...
  • Page 3 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 Manual 8.781.8002EN / 2014-07-31 jb/ebe...
  • Page 4 Teachware Metrohm AG CH-9100 Herisau teachware@metrohm.com This documentation is protected by copyright. All rights reserved. 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.

  • Page 5: Table Of Contents

    4 Operation ............31 The keypad ....................31 Operating concept ..................32 All key functions at a glance ..............33 Operating principles .................. 38 4.4.1 Configuration and method parameters ..........38 4.4.2 Editing menu entries ................38 4.4.3 Entering text ....................39 780/781 pH/Ion Meter, Manual...
  • Page 6 7 Various functions ..........85 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 Reports ....................... 96 780/781 pH/Ion Meter, Manual...
  • Page 7 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 Evaluation ....................138 780/781 pH/Ion Meter, Manual...
  • Page 8 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 Accessories ....................158 Warranty (guarantee) ................160 10 Index ..............163 780/781 pH/Ion Meter, Manual...
  • Page 9 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.

  • Page 11: Introduction

    Both instrument versions, the 781 pH/Ion Meter and the 780 pH Meter, are used for measuring pH, temperature and potential reliably and at high resolution. The 781 pH/Ion Meter differs from the 780 pH Meter by having an additional operating mode for the potentiometric determina- tion of the concentration by using ion-selective electrodes (Conc mode).
  • Page 12 (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.

  • Page 13: Parts And Controls

    1 Introduction 1.2 Parts and controls Fig. 2: Front view of the 780 pH Meter or 781 pH/Ion Meter LCD display Main function keys On/Off key Input, navigation and Key for switching the instrument on and function keys Each key has several functions;...

  • Page 14: Fig. 3: Rear View Of The 780 Ph Meter Or 781 Ph/Ion Meter

    1.2 Parts and controls Fig. 3: Rear view of the 780 pH Meter or 781 pH/Ion Meter Connection for potentiometric electrodes RS232 interface pH, ISE, redox or silver electrodes Connection for printer or PC with built-in or separate reference elec- trode;...

  • Page 15: Information About This Manual

    Attention This symbol indicates important information. Please read it carefully before you continue. Information This symbol indicates additional information and tips. TIP ! This symbol indicates information that may be of particular use to you. 780/781 pH/Ion Meter, Manual...

  • Page 16: Safety Information

    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.

  • Page 17: 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 guar- anteed.

  • Page 18: Connecting The Accessories

    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. Fig. 5: Attaching the support rod and base plate 780/781 pH/Ion Meter, Manual...

  • Page 19: Connecting Optional Devices

    Fig. 6: Ready-mounted pH/ISE measuring system The 801 Magnetic Stirrer is controlled via MSB connection 9. The stirrer is connected to it directly: Fig. 7: 780 pH Meter / 781 pH/Ion Meter – 801 Magnetic stirrer 780/781 pH/Ion Meter, Manual...

  • Page 20: Connecting The 802 Rod Stirrer

    Meter. This is done by plugging the MSB connection cable of the 804 Ti Stand into MSB connection 9 of the pH/Ion Meter: Fig. 8: 780 pH Meter / 781 pH/Ion Meter – 802 Rod stirrer 780/781 pH/Ion Meter, Manual...

  • Page 21: Connecting A Dosimat Plus (Only 781)

    Controlled addition of standard or sample solutions For automatic calibration as well as for the addition of standard or samples in the Conc mode with the 781 pH/Ion Meter the Metrohm 865 and 876 Dosimat Plus devices can be connected via the separately available 6.2148.010 Remote Box.

  • Page 22: Connecting A Sample Changer

    Connecting a sample changer For simple automated measurement of several samples and standards with the pH/Ion Meter the Metrohm Compact Sample Changer 869 can 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.

  • Page 23: Connecting A Printer

    (Metrohm ordering number: 2.140.0200) with the serial 6.2134.110 Ca- ble 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 Sec- tion 5.6)
  • Page 24 9600 interface Data Bit: A4 Paper Stop Bit: Parity: none Handshake: HP Desk Jet 2.145.0330 Character Set: see Printer Manual with parallel RS232/ Baud Rate: 9600 interface Parallel Data Bit: Converter Stop Bit: Parity: none Handshake: 780/781 pH/Ion Meter, Manual...

  • Page 25: Connecting A Computer

    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. Howev-...

  • Page 26: Connecting The Electrodes And Sensors

    2.4 Connecting the electrodes and sensors 2.4 Connecting the electrodes and sensors On its rear panel the 780/781 pH/Ion Meter has connections for a po- tentiometric electrode 5, a separate reference electrode 6 and a tem- perature sensor 8. Connect your electrodes and sensors according to the following dia- gram to the switched off pH/Ion Meter: Fig.

  • Page 27: Mains Connection

    (781 only). During the switch-on process an instrument checking routine is carried out automatically. If an error message is displayed here (' ') then Err x please contact your local Metrohm agency. 780/781 pH/Ion Meter, Manual...

  • Page 28: Initial Configuration

    Temperature sensor and unit CONFIG/auxiliaries/Temp.sensor and /Temp.unit Enter the type of temperature sensor that is connected. If no tempera- ture sensor is connected and you always want to enter the measuring temperature manually then you can ignore this setting. 780/781 pH/Ion Meter, Manual...

  • Page 29: Short Operating Tutorial

    8.5). The calibration parameters for the pH mode are set for a calibration us- ing 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. pH/Ion Meter installation •...

  • Page 30: Ph Calibration

    Result • Wait for potential measurement, result will be displayed: • After 30 s the pH/Ion Meter will switch back automatically to the measurement display. This can also be done immediately E NTE R with <ENTER>. 780/781 pH/Ion Meter, Manual...
  • Page 31 (calib short); this contains all the data except the calibration curve itself. • The Select key <->> offers the further option 'calib full'; this also outputs the calibration curve. 780/781 pH/Ion Meter, Manual...

  • Page 32: Ph Measurement

    'Drift' and take place only when the current drift condition is fulfilled (see Section 6.2.1): 781 pH/Ion Meter 01104 5.781.0020 date 2004-05-12 16:57:55 ******** run number electr.id pH = 5.875 20.2 °C Pt1000 ============== 780/781 pH/Ion Meter, Manual...

  • Page 33: Determination Of An Ion Concentration (Only 781: Conc Mode)

    (please refer to the Section mentioned for details). If you are not certain whether all the settings ( CONFIG PARAMETER Conc correspond to the original conditions you can first reset any alterations by initializing the memory ( ) (see Section 8.5). RAM Initialization 780/781 pH/Ion Meter, Manual...

  • Page 34: Calibrating The Fluoride Ise

    • In the calibration parameters set the number of standards to 5 and define the concentrations: PARAMETER Conc > calibration parameters no. of standards 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 780/781 pH/Ion Meter, Manual...
  • Page 35 Result • Wait for potential measurement, result will be displayed: • After 30 s the pH/Ion Meter will switch back automatically to the measurement display. This can also be done immediately E NTE R with <ENTER>. 780/781 pH/Ion Meter, Manual...
  • Page 36 (calib short); this contains all the data except the calibration curve itself. • The Select key <->> offers the further option ' calib full this also outputs the calibration curve (see Section 7.2.4). 780/781 pH/Ion Meter, Manual...
  • Page 37 U/mV dconc/% std. 1 5.00E-01 139.9 std. 2 2.50E+00 97.0 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 variance 0.014 slope -59.9 mV E(0) 120.8 mV c(blank) 0.00E+00 ppm ============== 780/781 pH/Ion Meter, Manual...

  • Page 38: Direct Measurement Of Fluoride

    15 s poststir pause The stirring rate can only be set when a Metrohm 8XX Stirrer is connected to the MSB interface. • The calculation parameters (<PARAM>) are then: PARAMETER Conc > calculation parameters : smpl.size...
  • Page 39 '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 electr.id smpl.size 10.0 mL F(-1) 25.7 ppm 23.6 °C Pt1000 ============== 780/781 pH/Ion Meter, Manual...
  • Page 40 3.2 Determination of an ion concentration (only 781: Conc mode) 780/781 pH/Ion Meter, Manual...

  • Page 41: Operation

    Most of the keys on the right-hand side have two functions: The num- bers to be entered and the navigation functions are shown in the center of the keys; the additional functions at their upper margin. 780/781 pH/Ion Meter, Manual...

  • Page 42: Operating Concept

    In the direct measuring modes measurement recording and evaluation (e.g. automatic printing and limit monitoring) continues in the back- ground. In the menu display it is also possible to change directly from the configuration to parameter input with <PARAM> and vice versa with <CONFIG>. 780/781 pH/Ion Meter, Manual...

  • Page 43: All Key Functions At A Glance

    <CAL> key starts a calibration. Starts measurement / Prints ME AS/ out measured value P R INT • In the pH, T, U and Conc(direct) modes the <MEAS/PRINT> key trig- gers a measuring sequence. • Depending on the configuration (see 780/781 pH/Ion Meter, Manual...
  • Page 44 Operating mode selection Cancels sequence • In the pH, T and U modes (780 pH • With the <MODE> key working se- MO DE Meter) and the pH, T, U and Conc...
  • Page 45 • With the <METHODS> key the selec- tion for loading, saving or deleting a method is opened (see Section 6.1). Report selection • Direct selection of the method memory report after <REPORT>. Enters the number '0' 780/781 pH/Ion Meter, Manual...
  • Page 46 The arrows determine the selection di- rection. Cursor control for text input • In the text editor the arrow keys are used to select the character to be en- tered and the <ENTER> key to enter 780/781 pH/Ion Meter, Manual...
  • Page 47 • The <ENTER> key is used to com- E NTE R 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. 780/781 pH/Ion Meter, Manual...

  • Page 48: Operating Principles

    Entries which can be edited are altered by entering a new value and confirming it with <ENTER>. E NTE R Numbers are entered directly with the number keys. Exponential notation can be activated directly with the <-/exp> key. 780/781 pH/Ion Meter, Manual...

  • Page 49: Entering Text

    Text input is terminated by exiting the text editor with <QUIT> and con- firming the entry with <ENTER>. However, if the whole entry is to be re- jected then <QUIT> must be activated a second time. 780/781 pH/Ion Meter, Manual...
  • Page 50 4.4 Operating principles 780/781 pH/Ion Meter, Manual...

  • Page 51: Configuration

    ( >moni- ). You can either enter whole numbers between 1 toring/validation and 9999 or call up the default value of 365 days with <CLEAR>. 780/781 pH/Ion Meter, Manual...

  • Page 52: Report

    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. 780/781 pH/Ion Meter, Manual...
  • Page 53 For single page printers (e.g. HP DeskJet) you can enter the special value ' ' with form <CLEAR> so that the printed page will automatically be produced by the printer after each report. 780/781 pH/Ion Meter, Manual...

  • Page 54: Printing Out Measured Values

    Here you can choose whether the date and time at which the measured value was recorded are to be included with each indi- vidual measured value. This can take place irrespective of wheth- er a report header is used. report header: once, always, OFF 780/781 pH/Ion Meter, Manual...
  • Page 55 You can also let a series of measurements run indefinitely without a fixed stop time and then stop it manually with <QUIT> if you select 'OFF' for this setting. 780/781 pH/Ion Meter, Manual...
  • Page 56 (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 (' '). In both cases termination is possible with <QUIT>. 780/781 pH/Ion Meter, Manual...

  • Page 57: Storing Measured Values

    (see Section 7.3). It is also possible to output all measured values as a report via the RS232 interface (see Section 7.2.8). 780/781 pH/Ion Meter, Manual...

  • Page 58: Auxiliaries

    Switch the instrument off and on if this set- ting has been changed. display: positiv, negativ You can choose whether you want to have a positive or negative dis- play presentation, e.g. in order to adapt it to the local lighting condi- tions. 780/781 pH/Ion Meter, Manual...
  • Page 59 (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' semicon- ductor).
  • Page 60 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 al- tered. It is included in the report header as part of the instrument Id. 780/781 pH/Ion Meter, Manual...

  • Page 61: Monitoring

    : ├ validation ├ service └ system test report The 780/781 pH/Ion Meter can inform you automatically about reoccur- ring quality monitoring tasks. validation: ON, OFF time interval 1...365...9999 d time counter 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 vali- dation process.

  • Page 62: Peripheral Units

    ' 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 calibra- tion of ion-sensitive electrodes. Analyses involving the addition of standard and sample solutions can also be automated in this way.
  • Page 63 5 Configuration strument is switched on. In such a case remove the connected key- board and switch on the instrument again. 780/781 pH/Ion Meter, Manual...

  • Page 64: Rs232 Settings

    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. 780/781 pH/Ion Meter, Manual...

  • Page 65: Methods / Parameters

    For each selection you can edit a method name with <ABC> or select one with <SELECT>. 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. 780/781 pH/Ion Meter, Manual...

  • Page 66: Ph Measurement (Ph Mode)

    A smaller value for the measuring parameter Drift pH requires a more stable measuring signal than a larger one. The set measuring parameter is al- so proportional to the measuring uncertainty of the measured value ob- tained. 780/781 pH/Ion Meter, Manual...
  • Page 67 You can choose whether the pH measurement is to be made while stir- ring 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-...

  • Page 68: Calibration Parameters

    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 dif- ferent from the drift for pH measurement (see Section 6.2.1). 780/781 pH/Ion Meter, Manual...
  • Page 69 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: 780/781 pH/Ion Meter, Manual...
  • Page 70 However, you can also calculate these values by linear interpolation and enter them. Missing pH definitions will otherwise be shown during the calibration by negative values; the calibra- tion will then be interrupted with the error message buffer not defined 780/781 pH/Ion Meter, Manual...
  • Page 71 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. 780/781 pH/Ion Meter, Manual...

  • Page 72: Limits Ph

    -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. 780/781 pH/Ion Meter, Manual...

  • Page 73: Plot Parameters

    Please note that sample identifications requested as a preselection be- fore the measurement will also be stored as an entry under CON- . This means that they are again available for the next FIG/report measurement. 780/781 pH/Ion Meter, Manual...

  • Page 74: Electrode Test

    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.

  • Page 75: Temperature Measurement (T Mode)

    This field is only used for information here and cannot be edited direct- delta measurement: ON, OFF The delta measurement permits the display of the measured value rela- tive to a freely selectable constant reference value: reference -999.9...0.0...999.9 °C 780/781 pH/Ion Meter, Manual...

  • Page 76: Limits T

    You can choose whether the pH measurement is to be made while stir- ring 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-...

  • Page 77: Plot Parameters

    Please note that sample identifications requested as a preselection be- fore the measurement will also be stored as an entry under CON- . This means that they are again available for the next FIG/report measurement. 780/781 pH/Ion Meter, Manual...

  • Page 78: Potential Measurement (U Mode)

    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 altered direct- 780/781 pH/Ion Meter, Manual...

  • Page 79: Limits U

    You can choose whether the pH measurement is to be made while stir- ring 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-...

  • Page 80: Plot Parameters

    Please note that sample identifications requested as a preselection be- fore the measurement will also be stored as an entry under CON- . This means that they are again available for the next FIG/report measurement. 780/781 pH/Ion Meter, Manual...

  • Page 81: Direct Ion Measurement (781 Only: Conc Mode)

    The name of the analyte can be selected here. The additional option ' allows the analyte to be determined to be given its own name and charge: ion name 7 ASCII characters ion charge -9...-1, 1...9 780/781 pH/Ion Meter, Manual...

  • Page 82: Measuring Parameters

    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 780/781 pH/Ion Meter, Manual...
  • Page 83 You can choose whether the pH measurement is to be made while stir- ring 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-...

  • Page 84: Calculation Parameters

    V total 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: 780/781 pH/Ion Meter, Manual...

  • Page 85: Calibration Parameters

    The temperature is then stored and indicated by the suffix ' man- ' in the report header. 780/781 pH/Ion Meter, Manual...
  • Page 86 With automatic standard addition the pH/Ion Meter carries out the cal- culation 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 780/781 pH/Ion Meter, Manual...

  • Page 87: Limits Conc

    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 780/781 pH/Ion Meter, Manual...

  • Page 88: Limits T

    Under CONFIG/print meas. the print criterion ' ' must be selected (see Section 5.2). value plot The scales of the measured values axes are determined by the follow- ing limits. 780/781 pH/Ion Meter, Manual...

  • Page 89: Preselections

    This allows an individual sample data input. Just as in the request for the sample identifications, the sample size re- quested here will also be stored under PARAMETER Conc/calcula- and is available for the request before the next tion parameters measurement. 780/781 pH/Ion Meter, Manual...

  • Page 90: Standard And Sample Addition (781 Only: Conc Mode)

    ├ dos.rate ├ no.of additions ├ V Exchange Unit └ stop V The exact technique of standard and sample addition in the Conc mode is described by the parameters selected under standard addi- tion sample addition 780/781 pH/Ion Meter, Manual...
  • Page 91 The possibility of terminating the ad- dition 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. 780/781 pH/Ion Meter, Manual...
  • Page 92 ' this check is carried out during the automatic ad- auto 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 pa- rameters must also be defined: 780/781 pH/Ion Meter, Manual...

  • Page 93: Preselections

    OFF The sample size and sample size unit parameters described under the calculation parameters (see Section 6.5.4) can also be requested be- fore each measurement. This allows a more individual input of the sample data. 780/781 pH/Ion Meter, Manual...
  • Page 94 6.6 Standard and sample addition (781 only: Conc mode) 780/781 pH/Ion Meter, Manual...

  • Page 95: Various Functions

    The calibration data apply only to this electrode and will change when a new electrode Id is set under the above measuring pa- rameters (see Section 6.2.2). 780/781 pH/Ion Meter, Manual...
  • Page 96 If a calibration interval has been defined under PARAMETERS pH/ cal- then it will be shown here. It ibration parameters/cal.interval can be used together with the calibration time given under . to c.dat estimate the time that the next calibration is due. 780/781 pH/Ion Meter, Manual...
  • Page 97 '. The measuring points of deleted buffers are also indi- deleted 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 780/781 pH/Ion Meter, Manual...
  • Page 98 < –> > 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 <QUIT>. 780/781 pH/Ion Meter, Manual...

  • Page 99: Conc Calibration Data (781 Ph/Ion Meter Only)

    +59.2 mV or -59.2 mV per ion charge at 25 °C. This value can be altered manually for test purposes. However, after- wards the information about the method will be missing from the list 780/781 pH/Ion Meter, Manual...
  • Page 100 If a calibration interval has been defined under PARAMETER Conc/ then it will be shown here. Calibration parameters/cal.interval It can be used together with the calibration time given under . to c.dat estimate the time that the next calibration is due. 780/781 pH/Ion Meter, Manual...
  • Page 101 With this option you can reject all the calibration data of an elec- trode Id. You are then in the same state as before the first calibra- tion: slope = +59.2 mV or -59.2 mV per ion charge, E(0) = 0 mV, c(blank) = 0. 780/781 pH/Ion Meter, Manual...
  • Page 102 < –> > If at least 2 calibration standards have been used then the calibration curve will be shown as a graph here. The graphics display is accessed  with < >: The display is exited with <QUIT>. 780/781 pH/Ion Meter, Manual...

  • Page 103: Addition/Subtraction Data (781 Ph/Ion Meter Only)

    If an electrode Id has been entered or selected before the calibration under then it PARAMETER Conc/measuring parameters/electr.id will be shown here. Later alterations of the parameters have no effects electr.id on the display of the addition data. 780/781 pH/Ion Meter, Manual...
  • Page 104 If the calibration temperature has been determined automatically by a connected temperature sensor then its type will be shown here ' or ' '). A manually entered temperature for the calibration Pt1000 will be indicated accordingly (' manual 780/781 pH/Ion Meter, Manual...
  • Page 105 The calibration function can be viewed as a plot. The graphics display is accessed with <  >: ∗ The first measuring point of the solution is marked by ' ' and the addi- tions with a '+'. This display is exited with <QUIT>. 780/781 pH/Ion Meter, Manual...

  • Page 106: Reports

    Output of all stored measured values mv memory Output of all existing reports During selection these reports can also be selected directly by using the key which has the corresponding function (e.g. <CAL.DATA> for a calibration report). 780/781 pH/Ion Meter, Manual...
  • Page 107 Meter again. In this way you avoid the accidental cancellation of a report output. The following pages show the arrangement of reports together with some types of reports. A description of an electrode test report is given in Section 8.6. 780/781 pH/Ion Meter, Manual...

  • Page 108: Arrangement Of A Report

    (measuring points, results, calibration or electrode test reports) this is in the form of a double line: ============== Each report to be triggered manually with <REPORT> is concluded with a single line: -------------- 780/781 pH/Ion Meter, Manual...

  • Page 109: Report Identification

    Metrohm Vesuv © 3.0 for Windows can identify the produced report by this identification and use it for further evaluation. The following report Ids exist for the 780 pH Meter and 781 pH/Ion Me- ter: Report Id Report name Availability...
  • Page 110 781 pH/Ion Meter 01104 5.781.0020 date 2004-05-28 17:00:56 user C. Weber pH-1 run number electr.id pH electr.01 Temperature scale pH scale Temperature curve pH curve lower limit pH upper limit pH 780/781 pH/Ion Meter, Manual...

  • Page 111: Calibration Report

    176.7 0.006 buffer 3 9.037 -115.4 0.009 variance 1.192 slope 99.44 % pH(0) 7.035 ============== *) dpH: Nominal pH value of the buffer – pH value which, at the mesured voltage, results from the regression analysis 780/781 pH/Ion Meter, Manual...

  • Page 112: Result Report (781 Ph/Ion Meter Only)

    U/mV dU/mV std.incr. 1 0.020 115.5 -64.5 std.incr. 2 0.026 95.5 -20.0 std.incr. 3 0.056 76.0 -19.5 std.incr. 4 0.123 55.6 -20.4 variance 0.080 slope -59.0 mV E(0) 117.7 mV c F(-1) 4.40 ppm ============== 780/781 pH/Ion Meter, Manual...

  • Page 113: Configuration Report

    Pt1000 temp.unit: device label beep: program 5.781.0020 >monitoring validation: service: system test report: >peripheral units character set: Dosimat: stirrer: keyboard: barcode: input >RS232 settings baud rate: 9600 data bit: stop bit: parity: none handshake: -------------- 780/781 pH/Ion Meter, Manual...

  • Page 114: Parameter Report

    The standard parameters following a memory initialization in the current mode are shown; in this case the pH mode with a connected tempera- ture sensor (see Section 8.5). Such parameters can be stored as a method (see Section 6.1). 780/781 pH/Ion Meter, Manual...

  • Page 115: Measured Values Memory Report

    Please note that this is a simple and rapid method of producing meas- ured values with their most important data. For the complete documen- tation of measured value results in the sense of the normal quality as- surance requirements you should select the automatic measuring point report instead. 780/781 pH/Ion Meter, Manual...

  • Page 116: User Method Report

    50 methods or calibration data. This num- ber can vary depending on the size of the individual data records. The size of the measured value memory (see Section 7.3) is independ- ent of this memory administration. 780/781 pH/Ion Meter, Manual...

  • Page 117: Measured Values Memory

    RS232 interface is made as a measured values memory report (see Section 7.2.8). This is done by pressing <REPORT> when in the measured values display and then selecting the measured values stored report directly with <RECALL>. 780/781 pH/Ion Meter, Manual...

  • Page 118: Show Measured Values

    In order to delete all measured values you should use <SELECT> in the above measured values memory menu to select the second choice and set it to ' '; then confirm this and the follow- del mv store: ing safety query with <ENTER>. delete ? 780/781 pH/Ion Meter, Manual...

  • Page 119: Limit Monitoring

    If a limit is exceeded then on the optionally available Remote Box a specific line will be switched to "active". A connected instrument (e.g. Metrohm Dosimat Plus) can then be used to control the monitored pro- cess (see Section 9.5). You can also connect the 2.731.0010 Relay Box to the Remote Box to control different instruments.

  • Page 120: How It Functions

    This means that the activation cancellation point is de- fined as the upper limit minus hysteresis and the lower limit plus hyste- resis. Set the hysteresis to zero, if you are just interested in an exact docu- mentation of limit overruns. 780/781 pH/Ion Meter, Manual...

  • Page 121: Setup

    The advantage is that the requested settings and parame- ters only have to be confirmed during repeated procedures. Please note that all disablements will be invalidated if a RAM-Init is car- ried out (see Section 8.5). 780/781 pH/Ion Meter, Manual...

  • Page 122: Input Assignment

    Start conc.cal. 9 └ <ENTER> The pH/Ion Meter can communicate with other Metrohm instruments via the optionally available Remote box (see Section 9.5). In special cases it may be a good idea to alter the assignments of the actions to be trig- gered to the signal impulses on input lines Input 1 to Input 4 (see Sec- tion 9.5.2).

  • Page 123: Troubleshooting - Messages - Maintenance

    The following table lists general problems that can occur during pH and ISE measurements. Possible causes and appropriate remedies are also described. 780/781 pH/Ion Meter, Manual...
  • Page 124 • Enter correct temperature of the solu- Manual temperature input incor- tion rect • Clean membrane or diaphragm Dirty pH or ISE membrane or diaphragm • Refill electrolyte or replace electrode Electrolyte or electrode too old • Replace electrode Faulty electrode 780/781 pH/Ion Meter, Manual...

  • Page 125: Messages

    Please note that you should not press <QUIT> to acknowledge a message while a report is being produced as this will cancel the re- port. The following table lists all the messages which could appear on the display of the pH/Ion Meter. 780/781 pH/Ion Meter, Manual...
  • Page 126 Potential difference be- 1. Change buffer tween 1st and 2nd buffer is <ENTER> 2. Press too small same standard Conc calibration Pot. difference between 1st 1. Change standard and 2nd standard < 6 mV <ENTER> 2. Press 780/781 pH/Ion Meter, Manual...
  • Page 127 • Only output primary measured value. buffer not pH calibration pH of a buffers has not Enter missing value in tem- Sec- defined been defined under Buff- perature table (see tion 6.2.2 er type: own for the given temperature 780/781 pH/Ion Meter, Manual...
  • Page 128 • Press <QUIT> RS error 43 Report output RS transmitter error: • Send XON transmission from the pH Meter has been interrupted by XOFF for at least three seconds 780/781 pH/Ion Meter, Manual...
  • Page 129 Mode T Temperature sensor is Connect a properly function- faulty or not connected ing temperature sensor transmission PC keyboard Communication problem Check keyboard connection error connecte with PC keyboard with instrument switched off 780/781 pH/Ion Meter, Manual...

  • Page 130: Qm Support

    Metrohm AG, Herisau. You can request them under www.metrohm.com or from your local Metrohm agency.
  • Page 131 All Metrosensor pH electrodes, ion- selective electrodes, reference electrodes and temperature sensors are supplied with the corresponding certificates. The same applies for buff- er solutions, which are supplied with batch-specific certificates. 780/781 pH/Ion Meter, Manual...

  • Page 132: Validation

    1. Checking the electronic components when the instrument is switched on. 2. Validation of the whole analytical system by wet chemistry. 3. pH/Ion Meter maintenance by Metrohm Service. 8.4.1 Electronic tests After the pH/Ion Meter has been switched on an electronic system test is carried out automatically.

  • Page 133: Wet Tests

    8.4.3 pH/Ion Meter maintenance In the same way as monitoring the validation interval, the pH/Ion Meter can also remind you that maintenance is due, e.g. by Metrohm Service (see Section 5.5). service is due 780/781 pH/Ion Meter, Manual...

  • Page 134: Diagnosis

    Metrohm Service personnel. If one of the following tests is concluded with an error message, please note it down and contact your local Metrohm agency. You are expressly warned against triggering any other functions other than those listed and documented below. Improper use can disturb the correct functioning of the pH/Ion Meter and may render it unusa- ble.

  • Page 135: Key Test

    However, the <ON/OFF> key will still switch off the pH/Ion Meter. This test is termi- nated by pressing the <CLEAR> key twice. 780/781 pH/Ion Meter, Manual...

  • Page 136: Ph Electrode Test

    Stirrer You require a stirrer for the test. We recommend the use of a Metrohm stirrer as this allows the electrode test to be carried out automatically. Information about the connection and configuration of such a stirrer is given in Section 5.6.

  • Page 137: Procedure

    The stirring rate should be set so that the stirring action is powerful but without the formation of air bubbles (avoidance of absorbing CO Metrohm stirrers which are connected to the pH/Ion Meter are switched on and off automatically when the measuring parameter...
  • Page 138 <ENTER>. • The instrument now counts down from 239 to 0 seconds. • If a Metrohm stirrer is connected and configured (see Sec- tion 8.6.1) then it will be switched off automatically after 3 minutes. Otherwise you will be requested to switch off the stir- rer;...

  • Page 139: Results

    Offset potential Uoff The offset potential Uoff, which is determined together with the slope and pH(0), is tested once against a preset limit and is not included in the evaluation. 780/781 pH/Ion Meter, Manual...
  • Page 140 (see follow- ing section). Instead of the stored tolerances for most Metrohm electrodes you can TIP ! set your own values (see Section 6.2.7). This may be helpful for spe-...

  • Page 141: Messages And Measures

    These measures are described in detail in the following Section. The first two tests are carried out after the measurement in the pH 9 buffer and the electrode test then stopped if necessary. 780/781 pH/Ion Meter, Manual...

  • Page 142: Care And Maintenance Of Ph Glass Electrodes

    • The reference electrolyte filling opening must remain open during the measurement and be closed during storage. • There should be no air bubbles in the inner or reference electro- lyte. • All cable connections should be clean and dry. 780/781 pH/Ion Meter, Manual...
  • Page 143 Then rinse with water and replace the reference electrolyte. • Note: Ultrasonic cleaning can destroy the electrode! Care of the glass membrane • When carrying out measurements in non-aqueous media the electrode should be hydrated between measurements. 780/781 pH/Ion Meter, Manual...
  • Page 144 8.6 pH electrode test 780/781 pH/Ion Meter, Manual...

  • Page 145: Annex

    9.1 Technical data Provided that nothing to the contrary is mentioned, the published val- ues represent the typical data of the 780 pH Meter and the 781 pH/Ion Meter. 9.1.1 Measuring modes Prim.

  • Page 146: Measuring Input Specifications

    Interfaces RS232 connection RS232 Hardware and software handshake for printer and re- mote control MSB connections (MSB = Metrohm Serial Bus) Stirrer Connection of max. 1 stirrer Stirrer control: manual on/off, or automatic during measuring sequence Rate selectable in 15 steps Remote box Connection of max.

  • Page 147: Safety Specifications

    After adjustment 9.1.10 Dimensions Housing material Polybutylene terephthalate (PBT) Keyboard material Polyester Display cover material Glass Width 305 mm Height (without stand) 55 mm Height (with stand) 410 mm Depth 170 mm Weight (without stand) 1378 g 780/781 pH/Ion Meter, Manual...

  • Page 148: Evaluation

    In fact this U/pH curve is usually different. The offset potential of the electrode (Uoff = U at pH 7.0) may not be zero as a result of the asymmetry potential at the glass membrane, a contaminated inner elec- 780/781 pH/Ion Meter, Manual...

  • Page 149: Fig. 16: 3-Point Ph Calibration

    Using this data the calibration curve can be described as follows: − lope ⋅ ⋅ − pH(0) − pH(0) resp. ⋅ lope 780/781 pH/Ion Meter, Manual...
  • Page 150 (linear regression) will be calculated. ∑ − ⋅ − ⋅ Slope ∑ − − − pH(0) − ⋅ Slope ∑ − calculated Variance = ;n = no. of measuring points − 780/781 pH/Ion Meter, Manual...
  • Page 151 For a pH calibration at least two or more different buffers should be used; these should cover the intended measuring range (DIN 19268). For example, you can obtain Metrohm buffer solutions for pH 4, 7 and 9 as ready-to-use solutions or concentrates (see Optional Accessories, Section 9.6).

  • Page 152: Calibration For Ion Measurements

    ⋅ Slope log( c(blank): Is set to zero and not shown. 2-Point calibration − Slope − log( log( ⋅ E(0) Slope log( log( , U = mean value c(blank): Is set to zero and not shown. 780/781 pH/Ion Meter, Manual...

  • Page 153: Addition Method

    (Sample size, Vtotal and Factor; see also Section 6.5.4) and shown directly. ⋅ ⋅ total Factor Smpl size If the parameter Smpl.size is set to ' ' then cA(Ion) will simply be mul- tiplied by Factor. 780/781 pH/Ion Meter, Manual...

  • Page 154: Menu Structures

    This so-called instrument tree can also be used to control the pH/Ion Meter via the serial interface. It is described in a separate document to- gether with the exact syntax used (780/781 pH/Ion Meter Operation via RS232, No. 8.781.1113). The document is available from your local Metrohm agency.
  • Page 155 ├ peripheral units │ ├ character set │ ├ Dosimat │ ├ stirrer │ ├ keyboard │ └ barcode │ └ RS232 settings ├ baud rate ├ data bit ├ stop bit ├ parity └ handshake 780/781 pH/Ion Meter, Manual...

  • Page 156: Method Parameters In The Ph Mode

    │ └ req.ident │ └ electrode test ├ ┬ electrode type standard, gel, non-aqu. │ └ ───┬ excellent electrode ├ ├ temperature good electrode └ ├ report passing Elektrode ├ l.limit Uoff └ u.limit Uoff 780/781 pH/Ion Meter, Manual...

  • Page 157: Method Parameters In The T Mode

    │ └ poststir oause ├ limits U │ └ ───── ──┬ state u.limit │ ├ u.hyst. ├ ├ plot parameters l.limit │ ├ └ left mar. l.hyst. │ └ right mar. │ └ preselections └ req.ident 780/781 pH/Ion Meter, Manual...

  • Page 158: Method Parameter In The Conc Mode

    ────┬ state u.limit │ ├ u.hyst. ├ ├ plot parameters l.limit │ ├ └ left mar. l.hyst. │ ├ right mar. │ ├ left marg.T │ └ right marg.T │ └ preselections ├ req.ident └ req.smpl.size 780/781 pH/Ion Meter, Manual...
  • Page 159 1...n │ │ └ stop V │ └ ──┬ auto delta U │ ├ dos.rate │ ├ no.of additions │ ├ V Exchange Units └ └ preselections stop V ├ req.ident ├ req.smpl.size └ activate pulse 780/781 pH/Ion Meter, Manual...

  • Page 160: Stored Buffer Series

    For automatic buffer recognition during pH calibration the temperature- dependent pH values of several common pH buffers are stored in the 780/781 pH/Ion Meter. Apart from the Metrohm buffer solutions other reference and technical buffers are also included in the tables.
  • Page 161 4.13 7.00 9.65 4.13 6.94 8.67 4.14 7.02 9.63 4.14 6.94 8.65 4.16 7.03 9.62 4.16 6.95 8.63 4.18 7.06 9.61 4.18 6.96 8.61 4.21 7.08 9.60 4.21 6.97 8.60 4.23 7.11 9.60 4.23 6.98 8.59 780/781 pH/Ion Meter, Manual...
  • Page 162 1.743 4.116 6.845 6.982 8.921 9.751 1.119 1.754 4.137 6.852 6.992 8.900 9.739 1.121 1.765 4.159 6.859 7.004 8.885 9.731 1.124 1.778 4.183 6.867 7.018 8.867 9.726 1.127 1.792 4.210 6.877 7.034 8.850 9.724 4.240 6.886 780/781 pH/Ion Meter, Manual...
  • Page 163 6.97 8.87 4.06 6.97 8.99 9.79 4.04 6.97 8.84 4.06 6.97 8.81 4.07 6.97 8.79 4.09 6.98 8.76 4.11 6.98 8.74 4.13 6.99 8.73 4.15 7.00 8.71 4.18 7.00 8.70 4.20 7.01 8.68 4.23 7.02 8.67 780/781 pH/Ion Meter, Manual...
  • Page 164 10.190 10.90 11.610 6.96 7.790 8.68 8.910 9.585 10.125 10.80 11.500 6.97 7.780 8.66 8.890 9.550 10.060 10.70 11.390 6.98 7.765 8.65 8.870 9.520 9.995 10.59 11.270 7.00 7.750 8.64 8.850 9.490 9.930 10.48 11.150 7.02 780/781 pH/Ion Meter, Manual...
  • Page 165 4.01 6.98 8.96 9.94 4.03 6.98 8.93 9.90 4.03 6.97 8.89 9.86 4.05 6.97 8.87 9.80 4.06 6.97 8.84 9.73 When using Merck CertiPUR (20 °C) buffers, you have to select the buffer type "Merck Titrisol". 780/781 pH/Ion Meter, Manual...

  • Page 166: Remote Box

    = low inactive = high Fig. 18: Pin occupancy at remote interface All the lines used by the 780/781 pH/Ion Meter are shown in bold type. The following applies for all outputs: V = 40 V = 20 mA >...

  • Page 167: Functions Of The Individual Remote Lines

    Sec. meas. value: if below lower limit: active (low) (781: with autom. addition: impulse for Dosimat Plus, t = 1.25 Puls +5 V I ≤ 40 mA, R ≈ 12 Ω 0 V: active (low), 5 V: inactive 14/25 780/781 pH/Ion Meter, Manual...

  • Page 168: Accessories

    The search results will be displayed. • In the search results, select the Devices tab (if it is not already selected) and then click on the Metrohm article number of the required instrument (e.g. 2.852.0050). The page with information pertaining to the searched article is displayed.
  • Page 169 The Partslists webpage will be displayed. • Select the desired output language. • Enter the article number and click on the Generate PDF com- mand. The PDF file with the accessories data will be created in the lan- guage selected. 780/781 pH/Ion Meter, Manual...

  • Page 170: Warranty (Guarantee)

    9.7 Warranty (guarantee) 9.7 Warranty (guarantee) Metrohm guarantees that the deliveries and services it provides are free of defects in materials, design or manufacturing. The general warranty period is 36 months (exclusions below) from the date of delivery, or 18 months in the event of continuous operation. The...
  • Page 171 This does not apply for software products sold under the Metrohm NIRSystems brand. If Metrohm AG is unable to meet this obligation due to circumstances beyond the control of Metrohm AG, then the ordering party shall be of- fered alternative solutions at preferential conditions. 780/781 pH/Ion Meter, Manual...
  • Page 172 9.7 Warranty (guarantee) 780/781 pH/Ion Meter, Manual...

  • Page 173: Index

    Auxiliaries ........ 48 Certificates ......121 Delta U Character set Parameter Conc Add ..83 Configuration ....52 Device label ......50 B value ........49 Clamping ring ......9 Diagnosis ......124 Barcode reader ..... 136 780/781 pH/Ion Meter, Manual...
  • Page 174 Conc addition data ..93 Results ......129 Input resistance ....135 Parameter Conc .... 71 Test criteria ....131 Installation ..... 7, 19, 23 Parameter Conc Add ..80 Electrode type Instrument description ....1 MEAS/PRINT ......99 780/781 pH/Ion Meter, Manual...
  • Page 175 Metrodata Vesuv 3.0 ....15 Printer PARAMETER U ....... 68 Configuration ....52 Metrohm buffers ..... 59 Parameters Connection ....13 Metrohm Serial Bus ....136 Description ....55 Program ........50 Min.conc. Menu structure ..... 146 Pt1000 Calibration parameter Parity ........
  • Page 176 Print criterion ....45 Measuring parameter T . 66 Connection ....12 Storage criterion .... 47 Measuring parameter U 69 Sample identification Time counter Stirring sequence Parameter Conc .... 79 Validation ....... 51 Parameter Conc Add ..83 780/781 pH/Ion Meter, Manual...
  • Page 177 Parameters ....68 V init Version number ....... 50 U/pH curve ......138 Calibration parameter Very good electrode ..... 130 Conc ......77 Unit Ion parameters ....72 V total Calc. parameter Conc ... 74 Uoff 780/781 pH/Ion Meter, Manual...

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