Mettler Toledo D77, DL70ES, DL67 Operating Instructions Manual

Download

Operating Instructions

METTLER TOLEDO

DL77

DL70ES

DL67 Titrators

RESET

EXIT

RUN

1. INSTALLATION

2. EDITOR

3. ANALYSIS

4. AUXILIARY FUNCTIONS

5. DOCUMENTATION

6. USER LEVEL

7. REMOTE CONTROL

8. Designations – Explanations – Examples

9. Error messages and malfunctions

10. Applications

11. Installation instructions, Technical data, Accessories

12. Index, Certificates & Declarations

Introduction

Safety measures

The titrators have been tested for the experiments and intended purposes documented in the Tutorial and these Operating Instructions. However, this does not absolve you from the responsibility of performing your own tests of the products supplied by us regarding their suitability for the methods and purposes you intend to use them for. You should therefore observe the following safety measures.

Measures for your protection

– Ensure that you plug the power cable supplied into a receptacle outlet that

is grounded! In the absence of grounding, a technical fault could be lethal.

– Switch the instrument off and disconnect the power cable before you open

Risk of electric

shock

the housin or change blown fuses! An electric shock could be lethal.

– Never work in an environment subject to explosion hazards! The housing

of the instrument is not gas tight (explosion hazard due to spark formation, corrosion caused by the ingress of gases).

Risk of explosion

– Always test the titration vessel for firm seating in the titration head! If it falls

off, you could injure yourself if working with toxic titrants and solvents or strong acids or bases.

Risk of corrosion

– When using chemicals and solvents, comply with the instructions of the

producer and the general lab safety rules! Additional safety precautions for Karl Fischer titrations are described in Section 10.2.

Measures for operational safety

– Check the set operating voltage before you switch on the titrator (see

Section 11.1.5)! The instrument will be damaged if the operating voltage does not match the line voltage.

Caution

– Use only fuses of the specified type if you need to change them!– Have

the instrument serviced only by METTLER TOLEDO Service!

– Always wipe off splashed liquids immediately! The instrument is not water-

proof.

– Exclude the following environmental influences:

• powerful vibrations,

• direct sunlight,

• atmospheric humidity greater than 80%,

• temperatures below 5 °C and above 40 °C,

• powerful electric or magnetic fields!

02/93 METTLER DL77/DL70ES/DL67 1

11/97

Introduction

METTLER DL77/DL70ES/DL67

02/93

Introduction

The DL77, DL70 ES, and DL67 METTLER titrators are microprocessor-controlled analytical instruments that provide accurate and reproducible results thanks to their built-in intelligence.

With these titrators, you can perform end point, equivalence point and pH-stat titrations, measure pH/mV and temperature, and determine TAN/TBN and p/m values. With the aid of a polarization current source, you can determine water contents by the Karl Fischer method (>2 mg H2O/sample). You can perform conductivity measurements and conductometric titrations with an appropriate non-Mettler unit equipped with an analog output.

All titrators have a maximum of four inputs for electrodes, two for temperature sensors and three 24-V outputs for stirrer, pump or valve attachments. They have a maximum of four RS232C/CL interfaces, enabling you to connect a series of peripheral instuments:

- an attached METTLER balance transfers the sample weight automatically,

- a printer records the desired results,

- a color terminal serves as a second display and can be used for remote control, or a PC/robot can interchange data with the titrator, and

- with an attached METTLER Sample Changer, each titrator is turned into a titration system for the automatic analysis of whole series of samples.

How the three titrators differ from each other DL77: Two titrations can be executed simultaneously and two sample changers can be

connected. Neither the DL70ES nor the DL67 allow this.

DL77/ These titrators can control a maximum of four burette drives, the DL67 two. DL70ES:

These instruments know the most important titrants and all METTLER sensors, whereas the DL67 knows one titrant and one sensor.

With both titrators a maximum of 10 titration methods can be entered in a list and processed in succession. With the DL67 one method can be entered at a time.

While a titration is running, you can develop and save a new method, or you can enter sample data for the next titration method. This is not possible with the DL67.

02/93 METTLER DL77/DL70ES/DL67 3

Introduction

Operating concept

What information will you find where?

1. The TUTORIAL, provided with the standard equipment, will help you to overcome any inhibitions you may have with regard to the new instrument. You will get to know the function keys, the keypad and the display. Using a stored method for an acid-base titration, you will perform your first analysis.

2. These Operating Instructions provide a complete description of the concept and oper- ating characteristics of the three titrators. The operating concept and a compilation of the key combinations follow this introduction.

3. The RS232C Interface Description, i.e., a detailed description of the communication bet- ween titrator and computer, is provided with the standard equipment (since June, 1999).

Note: These Operating Instructions apply to software version 3.0 or 3.1.

The organization of the Operating Instructions

The organization is based on a modular principle. This allows supplementation or the interchange of individual sections or pages: new text sections carry the date of issue (in the footer on every page).

The operating concept of the titrator

The operation of the titrator is menu driven. What does this mean? The titrator handles various tasks:

It stores, for instance, titrant names with the corresponding concentrations; it knows that it must terminate the titration after an equivalence point has been found; it rinses burettes and can provide records of stored data on an attached printer.

We call the listing of these various tasks a menu. Each task is subdivided further. If you select a task from the main menu you are shown a new set of tasks – the submenu – from which you can select another task. We refer to this as a menu tree when the main menu branches into submenus and these in turn into additional submenus.

METTLER DL77/DL70ES/DL67

05/99

02/93

Introduction

02/93 METTLER DL77/DL70ES/DL67 5

Introduction

METTLER DL77/DL70ES/DL67

02/93

Introduction

Key combinations

Rapid menu change with key combinations

In the Tutorial, you have already become acquainted with several key combinations which you can employ to obtain a certain menu immediately. Using these keys, you can reduce the number of keystrokes before and during the titrations considerably. The key combinations consist of the index key and a letter key which must be pressed simultaneously. Key combinations exist to

• jump from a submenu into the main menu or from a submenu into that of another branch, or to

• trigger commands for the burette or the printer (see below)

If you press a key combination in a submenu, the DL70 stores all changes that you have made up to this point in the menu. The selector bar can be on any line of the menu.

Key combinations for commands

Rinse burette (see Section 4.1.1) Rinse tip (see Section 4.1.2) Trigger line feed on the printer (see Section 1.8.1) Trigger form feed on the printer (see Section 1.8.1) The current display is printed (copied!)

Key combinations for menu change

MAIN MENU INSTALLATION EDITOR

ANAL YSIS A ANALYSIS B* AUXILIARY FUNCTIONS DOCUMENTATION USER LEVEL REMOTE CONTROL

* only DL77

only if computer is installed

Installation Titrants Sensors

02/93 METTLER DL77/DL70ES/DL67 7

Temperature sensors Auxiliary reagents Auxiliary instruments Auxiliary values Titration stands Peripherals Miscellaneous

Introduction

Key combinations

Editor Method ID METTLER methods User methods New method

Method

Auxiliary functions 1 Burette 2 Stirrer 3 Sensor

4 Temperature 5 Sample changer 6 Auxiliary instrument 7 Calibration temperature sensors 8 Offset adjustment sensor inputs

Documentation Print Data transfer Memory copy

Method Add*

Method Add

*DL67: Load A: only DL77

only DL77

only if sample changer is installed only if temperature option has been built in

No. ID2 Wt./vol.

1/1 1/2 1/3

0.0000 g

E –V curve

Sample data list for the current method (example)

Display of the method function for the current method (Titration function active)

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Contents Page

1. INSTALLATION........................................................................................... 1-3

1.1 Titrants ........................................................................................................ 1-4

1.1.1 Delete........................................................................................................... 1-4

1.1.2 Modify........................................................................................................... 1-4

1.1.3 Add............................................................................................................... 1-8

1.2 Sensors ....................................................................................................... 1-9

1.2.1 Delete........................................................................................................... 1-10

1.2.2 Modify........................................................................................................... 1-10

1.2.3 Add............................................................................................................... 1-14

1.3 Temperature sensors................................................................................. 1-15

1.4 Auxiliary reagents ...................................................................................... 1-17

1.4.1 Delete........................................................................................................... 1-17

1.4.2 Modify........................................................................................................... 1-17

1.4.3 Add............................................................................................................... 1-18

1.5 Auxiliary instruments ................................................................................ 1-20

1.5.1 Delete........................................................................................................... 1-20

1.5.2 Modify........................................................................................................... 1-20

1.5.3 Add............................................................................................................... 1-21

1.6 Auxiliary values.......................................................................................... 1-23

1.7 Titration stands .......................................................................................... 1-25

1.8 Peripherals.................................................................................................. 1-28

1.8.1 Printer........................................................................................................... 1-28

1.8.2 Balance ........................................................................................................ 1-30

1.8.3 System ......................................................................................................... 1-32

1.8.4 Sample changer ........................................................................................... 1-35

02/93 METTLER DL77/DL70ES/DL67 1-1

INSTALLATION

Page

1.9 Miscellaneous............................................................................................. 1-36

1.9.1 Format date/time .......................................................................................... 1-36

1.9.2 Enter date/time ............................................................................................. 1-36

1.9.3 Language ..................................................................................................... 1-37

1.9.4 Record header ............................................................................................. 1-37

1.9.5 Titrator ID ..................................................................................................... 1-37

1.9.6 Routine level ................................................................................................ 1-38

1.9.7 Audio signal.................................................................................................. 1-39

1.9.8 Analysis parameters..................................................................................... 1-40

1-2

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

1. INSTALLATION

In order to perform titrations the titrator must be acquainted with the titrants and their concentration, the sensors with their possible unit of measurement, and the solvents that it can dispense by means of pumps. It must know the burette drive on which the burette is located, the input to which the sensor is connected and what output carries the stirrer. It needs the names of the attached units such as a balance or printer in order to transfer data. In this menu you enter and store the names of all chemical and mechanical resources: you install them.

The most common titrants, solvents and all METTLER sensors are already installed in the titrator. Not only can you delete these resources or modify their parameters, but you also have the possibility to install new ones.

List of resources Titrants

Sensors Temperature sensors Auxiliary reagents Auxiliary instruments Auxiliary values Titration stands Peripherals Miscellaneous

Caution: All resources needed for the METTLER methods stored in the application data

base are installed accordingly. If you delete one of these, the titrator will wait until start of titration of a METTLER method before outputting the error message that the resource is not installed.

DL67: Only the titrant and the sensor for METTLER method M001 are stored in the DL67.

02/93 METTLER DL77/DL70ES/DL67 1-3

Titrants

INSTALLATION

1.1 Titrants

When you select this menu you receive the installed titrants with the specified parameters concentration and burette drive. (You will find the menu tree depicted at the end of Section

1.1.2.)

NaOH 0.1 mol/L Drive 3 HCl

HClO

etc...

DL67: The DL67 only has stored the titrant NaOH. You can, however, add titrants to the list

(see Section 1.1.3).

If you select, for instance, NaOH the list will be masked on the right by a selection menu containing the following commands:

0.1 mol/L Drive 3

Delete Modify Add

1.1.1 Delete

Position the selector bar on this command and confirm with RUN. The mask of the selection menu disappears, the titrant NaOH is deleted.

Note: You can also delete a titrant directly from the list by pressing the <–> (minus) key. You

can reinstall NaOH with the command Add (see Section 1.1.3).

1.1.2 Modify

If you select this command you are shown the parameter mask of the titrant (see next page). If you move the selector bar to one of these parameters you can modify its name or value.

Note: a. Default values are stored in the titrator for all parameters, e.g. for the concentration

of the titrant 0.1 mol/L, for the titer 1.0.

1-4

• These values will be overwritten once you have entered new ones.

• If you want to modify only one digit of a value, you must first indicate the digit with the cursor (with → or ←) prior to entering the new one.

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Titrants

Note: b. With many parameters the titrator has selection or recommendation menus in which

you need only select the values or names. If a parameter has one of these menus, each time it is selected an arrow symbol (➡) appears at the extreme right in the middle of the display. You can either accept the value or name following the parameter or:

in the case of Recommendation,

– overwrite directly with a new entry or – press SEL to select a new value or name from the recommendation menu that

appears.

in the case of Selection, – press SEL to select a new value or name from the selection menu that appears.

You cannot enter the value or name yourself. If only two names or values are possible for a parameter, these are toggled

automatically with SEL.

Name NaOH Concentration [mol

/L]

0.1 Titer 1.0 Burette volume 10 mL Burette drive Drive 3 Date/time (e.g.: 07–06–1992 12:20)

1. You can overwrite the name or press SEL to call up the recommendation menu:

Recommendation menu: You can select a new titrant from the recommendation menu.

Position the selector bar on, for instance, HCl and confirm with RUN. The recommendation menu disappears and HCl follows Name.

2. Enter the concentration [mol/L]

3. Enter the titer only if you know its value. If you determine the titer of the titrant with the

titrator, its value is entered here together with the date automatically (see

Titer

function,

Section 2.3.16).

4. Select the burette volume from the selection menu:

Selection menu: You press SEL, position the selector bar on, for instance, 5 mL in the selection menu and confirm with RUN. The selection menu disappears and 5 mL now follows burette volume.

5. Select the burette drive from the selection menu.

02/93 METTLER DL77/DL70ES/DL67 1-5

Titrants

INSTALLATION

DL67: It is only possible to select one of two burette drives for this titrator. If more than two

drives have been installed, the titrator will recognize each of the first two (counting from left to right).

6. You can neither delete nor overwrite the date. It refers to the titer determination of the titrant using the method function (see

Titer

function, Section 2.3.16).

Titer

and is entered here together with the time automatically

Note: As soon as you change a titrant parameter, the date and time are deleted.

The titrant with the modified parameters is installed when you quit the parameter mask with EXIT. Here, the selector bar can be positioned on any parameter, but not on the title line.If you confirm the title line with EXIT the following selection menu appears:

Save modifications? Yes No

If you confirm "Yes" with RUN, the titrator stores the modified values or names. If you confirm "No" with RUN, the old values remain in force.

Note: If you press a key combination (<index + letter>) to quit the Installation menu, the

modified parameters are stored automatically if the selector bar is positioned on a parameter line. If it is positioned on the title line, the selection menu "Save modifications?" appears again (see above).

1-6

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Menu tree

Titrants

Titrant NaOH HCl HClO etc.

Selection

0.1 mol/L

Drive 3 Drive 3 Drive 3

Delete Modify Add

The titrant is deleted

Titrant parameters Name Concentration [mol/L] Titer Burette volume Burette drive Date/time

Enter new name or select entry from recommendation menu with SEL

Enter new concentration

NaOH

0.1

1.0 10 mL Drive 3 (07-06-1992 12:20)

Titrant names NaOH HCl HClO

etc.

Enter new titer or let it be entered through titration

Select another burette with SEL

Burette volume 1 mL 5 mL 10 mL 20 mL

Select another drive with SEL

Burette drive Drive 1 Drive 2 Drive 3 Drive 4

Date/time is entered only through titer determination by the titrator!

02/93 METTLER DL77/DL70ES/DL67 1-7

Titrants

INSTALLATION

1.1.3 Add

Select this command if you wish to add a titrant to the titrant list, for instance NaOH of concentration 1.0 mol/L or with a different burette volume, or a new titrant. You can also add a titrant directly to the list by pressing the <+> (plus) key. You are always shown the following mask:

Name NaOH Concentration [mol

/L]

0.1 Titer 1.0 Burette volume 10 mL Burette drive Drive 3 Date/time 00–00–0000 00:00

1. Select the titrant from the recommendation menu or enter the one you wish to install. Note: If you install, for example, several NaOH solutions of the same concentration, you must

provide each name with a different flag to allow the titrator to distinguish between them, e.g. NaOH/1.

2. Enter the concentration [mol/L].

3. Enter the titer only if you know its value. If you determine the titer with the titrator, its value

together with the date is entered here automatically (see

Titer

function, Section 2.3.16).

4. Select the burette volume from the selection menu.

5. Select the burette drive from the selection menu.

6. The date together with the time for the newly installed titrant is entered here automatically

only after the titer has been determined (see

Titer

function, Section 2.3.16).

The titrant with the appropriate parameters is installed when you quit the parameter mask with EXIT (see the appropriate description at the end of Section 1.1.2).

1-8

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Sensors

1.2 Sensors

When you select this menu you are shown the installed sensors with the specified parameters unit of measurement and the sensor input. (You will find the menu tree depicted at the end of Section 1.2.2.)

DG111-SC pH Sensor 1 (Combined pH electrode – aqueous medium) DG101–SC pH Sensor 1 (Combined pH electrode for small volumes in a

small titration vessel – aqueous medium)

DG113–SC mV Sensor 1 (Combined glass electrode with movable sleeve

frit – nonaqueous medium)

DG114–SC mV Sensor 1 (Combined glass electrode with movable sleeve

frit – aqueous medium)

DG115–SC mV Sensor 1 (Combined glass electrode with sleeve frit –

aqueous medium)

DM140–SC mV Sensor 2 (Combined platinum ring electrode – redox

titrations)

DM141–SC mV Sensor 2 (Combined silver ring electrode – argentometry) DM142 mV Sensor 1 (Double-pin platinum electrode – voltametry) DP550 % T Sensor 2 (Phototrode – transmission measurements at

550 nm)

DP660 % T Sensor 2 (Phototrode – transmission measurements at

660 nm)

DL67: Only sensor DG111-SC is stored in the DL67. You can, however, add sensors to the

list (see Section 1.2.3).

Note: There is no need to install a reference electrode as it is part of the installed measuring

electrode at input sensor 1. The input for the reference electrode is marked (see Section 11.1.4).

If you select DG111-SC, for instance, the list is masked on the right by a selection menu containing the following commands:

Delete Modify Add

02/93 METTLER DL77/DL70ES/DL67 1-9

Sensors

INSTALLATION

1.2.1 Delete

Position the selector bar on this command and confirm with RUN. The mask of the selection menu disappears, the DG111-SC sensor is deleted.

Note: You can also delete a sensor directly from the list by pressing the <–> (minus) key. You

can reinstall the DG111-SC with the Add command (see Section 1.2.3).

1.2.2 Modify

If you select this command you are shown the parameter mask of the sensor in which you can change the parameter values:

Name DG111-SC Unit of measurement pH Sensor input Sensor 1 Zero point [Unit] 7.0 Slope [mV/Unit] –59.16 Temperature [°C] 25.0 Date/time (e.g.: 02–06–1992 10:15)

1. Select the sensor name from the recommendation menu or enter the one you wish to install

in place of the DG111-SC sensor.

2. Select the unit of measurement suitable for the sensor from the selection menu. Within a

method you can later again choose between the selected unit of measurement and "mV" in the functions Measure, Titration and pH/mV-stat (see Section 2.3.4/ 12/13).

mV: Either there is no other unit of measurement suitable for the sensor, or you

require only mV. If you select the unit mV for a sensor, the calibration parameters zero point, slope and temperature are ignored by the titrator.

pH: After you select pH you then enter the calibration parameters for a pH electrode

or you let the titrator do it (see notes a. and b. on page 1-12).

pM: M represents any cation. After you select pM you then enter the calibration

parameters for a pM electrode or you let the titrator do it (see notes a. and b. on page 1-12).

pX: X represents any anion. After you select pX you then enter the calibration

parameters for a pX electrode or you let the titrator do it (see notes a. and b. on page 1-12).

1-10

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Sensors

%T: After you select %T you then enter the calibration parameters of a phototrode

(unit of measurement: transmission, see

Operating Instructions "Phototrode"

A: After you select A you then enter the calibration parameters of a phototrode

(unit of measurement: transmission. The absorption (A = -log T) is calculated, see

Operating Instructions "Phototrode"

µS/cm: After you select µS/cm you then enter the calibration parameters of the conduc-

tivity cell.

mS/cm: After you select mS/cm you then enter the calibration parameters of the conduc-

tivity cell.

Note: Conductivity measurements and conductivity titrations can be performed using a

conductometer equipped with an analog output.

3. Select the sensor input from the selection menu.

Notes: a. In the standard configuration of the titrator you have the sensor 1 and sensor 2 input

available. You should select the sensor 1 input for all glass electrodes as this has the highest input resistance (see

Technical data

, Section 11.2.1)

Rear view of the titrator

, Section 11.1.4 and

b. For technical reasons, only the "low resistance" sensor input 2 may be selected for

phototrodes (see Section 11.2.1)

Rear view of the titrator

, Section 11.1.4 and

Technical data

Caution: The RS option has an additional "low resistance" sensor input, the temperature

option an additional high resistance sensor input (see Sections 11.1.6 and 11.1.7). Depending on the installation manner, the "low resistance" input may, for example, be either sensor 3 or sensor 4! (See

Technical data

, Section 11.2.1).

Rear view of the titrator,

Section 11.1.4 and

4. Enter the zero point of the sensor: The zero point of a sensor is the measured value at which it displays 0 mV potential (zero

point of electrode assembly).

• For the zero point of a pH electrode this is pH0 with unit pH.

• For the zero point of an ion-selective electrode this is pM0 with the unit pM, or pX0 with

the unit pX.

• The zero point of the phototrode is normally 0% T (100% T = 1000 mV).

• The zero point of a conductivity cell is normally 0 µS/cm or 0 mS/cm.

02/93 METTLER DL77/DL70ES/DL67 1-11

Sensors

INSTALLATION

5. Enter the slope of the sensor. The slope of a sensor is the potential change in mV per unit of measurement.

• For the slope of a pH electrode the unit is: mV/pH.

• For the slope of an ion-selective electrode the unit is: mV/pM or mV/pX.

• The slope of a phototrode is normally 10 mV/ %T.

• For the slope of a conductivity cell the unit is: mV/µS*cm

-1

or mV/mS*cm-1.

6. Enter the temperature: The actual calibration temperature is either

• defined by you when starting a calibration method (see Section 3.1) or

• measured automatically if you have attached and installed a temperature sensor (see Sections 1.3, 2.3.2 and 2.3.17).

7. You can neither delete nor overwrite the date. It refers to the calibration of the sensor using the method function (see

Calibration

and is entered here together with the time automatically

function, Section 2.3.17).

Notes: a. The calibration parameter values of the titrator installed in the factory are theoretical

values for a new sensor. You have to perform a calibration of your sensor if you wish to determine accurate values (see

Calibration

function, Section 2.3.17).

b. When a pH, pM or pX sensor is calibrated the calibration parameters (zero point,

slope, temperature) are entered here automatically.

c. As soon as you change a sensor parameter, the date and time are deleted.

Caution: Do not transfer the calibration data obtained for glass electrodes attached to sensor

input 1 (or for the temperature option sensor input) to the electrodes you attach to sensor input 2 (or the sensor input of the RS option)! Recalibrate these sensors to obtain correct values!

The sensor with the modified parameters is installed when you quit the parameter mask with EXIT (see the appropriate description at the end of Section 1.1.2).

1-12

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Menu tree

Sensors

Sensors DG111-SC DG101-SC DG113-SC DG114-SC DG115-SC DM140-SC DM141-SC DM142 DP550 DP660

pH pH mV mV mV mV mV mV %T %T

Sensor 1 Sensor 1 Sensor 1 Sensor 1 Sensor 1 Sensor 2 Sensor 2 Sensor 1 Sensor 2 Sensor 2

Sensor parameters Name Unit of measurement Sensor input Zero point [unit] Slope [mV/unit] Temperature [°C] Date/time

Enter new name or select entry from recommendation menu with SEL

DG111-SC pH Sensor 1

7.0

-59.16

25.0 (02-06-1992 10:15)

Selection Delete Modify Add

The sensor is deleted

Sensor names DG111-SC DG101-SC DG113-SC etc.

Select another unit of measurement with SEL

Select another input with SEL

Enter new zero point or let it be entered through calibration

Enter new slope or let it be entered through calibration

Enter new temperature

Date/time is entered only through calibration by the titrator!

Units of meas. mV pH pM etc.

Sensor inputs Sensor 1 Sensor 2 Sensor 3 Sensor 4

02/93 METTLER DL77/DL70ES/DL67 1-13

Sensors

INSTALLATION

1.2.3 Add

Select this command if you wish to add a sensor to the sensor list, for instance a DG111-SC sensor with different calibration parameters or a sensor not yet installed. You can also add a sensor directly to the list by pressing the <+> (plus) key. You are always shown the following mask:

Name DG111-SC Unit of measurement mV Sensor input Sensor 1 Zero point [Unit] 7.0 Slope [mV/Unit] –59.16 Temperature [°C] 25.0 Date/time 00–00–0000 00:00

1. Select the sensor name from the recommendation menu or enter the name of the sensor you wish to install.

Note: If you install, for example, several DG111-SC sensors, you must provide each name

with a different flag to allow the titrator to distinguish between them, e.g. DG111/2.

2. Select the unit of measurement suitable for the sensor from the selection menu.

3. Select the sensor input from the selection menu.

4. Enter the zero point of the sensor.

5. Enter the slope of the sensor.

6. Enter the temperature. (see explanation of the parameters and note under

Modify

7. The date together with the time for the newly installed sensor is entered here automatically only after the sensor has been calibrated (see

Calibration

function, Section 2.3.17).

The sensor with the appropriate parameters is installed when you quit the parameter mask with EXIT (see the appropriate description at the end of Section 1.1.2).

1-14

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Temperature sensors

1.3 Temperature sensors

When you select this menu you are shown the installed temperature sensors with the specified parameters sensor type and sensor unit:

TEMP A Pt100 Temp 1 TEMP B Pt100 Temp 2 TEMP C Pt1000 Temp 1 TEMP D Pt1000 Temp 2

You can neither delete a temperature sensor nor add a new one to the list. You can, however, install several Pt100 or Pt1000 at the same temperature sensor input (Temp 1 or Temp 2), for example.

If you select TEMP A, for instance, you are shown the parameter mask of the Pt sensor in which you can change the parameter values or names:

Name TEMP A Sensor type Pt100 Sensor input Temp 1 Zero point [°C] 0.0 Date/Time 00–00–0000 00:00

1. You can not change the sensor name: The line will be skipped when the selector bar is moved.

2. Select the sensor type with SEL: "Pt100" or "Pt1000" (see Section 11.1.7).

3. Select the sensor input with SEL: "Temp 1" or "Temp 2" (see Section 11.1.4).

4. Enter the zero point of the Pt sensor. The zero point of a Pt sensor is the deviation of a measured value from a reference value,

such as 0 °C for an ice bath.

5. You can neither delete nor overwrite the date. It refers to the calibration of the Pt sensor using the auxiliary function

Calibration temperature sensors

and is entered here together

with the time automatically (see Section 4.7).

Notes: a. The installed zero point is the theoretical value for a new Pt sensor. You have to

perform a calibration of your sensor if you wish to determine an accurate value. When calibrating, the zero point is automatically entered here together with the date (see auxiliary function

Calibration temperature sensors

, Section 4.7).

b. As soon as you change a parameter of the temperature sensor, the date and time

are deleted.

02/93 METTLER DL77/DL70ES/DL67 1-15

Temperature sensors

INSTALLATION

The Pt sensor with the modified parameters is installed when you quit the parameter mask with EXIT (see the appropriate description at the end of Section 1.1.2).

Menu tree

Temperature sensors TEMP A TEMP B TEMP C TEMP D

Pt100 Pt100 Pt1000 Pt1000

Temp 1 Temp 2 Temp 1 Temp 2

Temperature sensors Name Sensor type Sensor input Zero point [°C] Date/time

The name cannot be changed

Select the other type with SEL: Pt1000

Select the other input with SEL: Temp 2

Enter new zero point or let it be entered through calibration!

TEMP A Pt100 Temp 1 0 00-00-0000 00:00

1-16

Date/time is entered only through zero-point calibration by the titrator

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Auxiliary reagents

1.4 Auxiliary reagents

When you select this menu you receive the installed auxiliary reagents with the specified parameters dispensing rate and auxiliary output. An auxiliary reagent is a solvent that is dispensed using a time-controlled device, e.g. a diaphragm pump or an electromagnetic valve. (You will find the representation of the menu tree at the end of Section 1.4.3).

H2O 250 mL/min Aux.2 CH3OH 250 mL/min Aux.2 CHCl

etc.

DL67: Only auxiliary reagent H2O is stored in the DL67. You can, however, add auxiliary rea-

gents to the the list (see Section 1.4.3).

If you select H2O, for instance, the list is masked on the right by a selection menu containing the following commands:

250 mL/min Aux.2

Delete Modify Add

1.4.1 Delete

Position the selector bar on this command and confirm with RUN. The mask of the selection menu disappears, the auxiliary reagent H2O is deleted.

Note: You can also delete an auxiliary reagent directly from the list by pressing the <–> (minus)

key. You can reinstall H2O with the command Add (see Section 1.4.3).

1.4.2 Modify

If you select this command you are shown the parameter mask of the auxiliary reagent in which you can change the parameter values:

Name H2O Dispensing rate [mL/min] 250 Auxiliary output Aux.2

1. Select the name of the auxiliary reagent from the recommendation menu or enter the name of the reagent you wish to install in place of H2O.

02/93 METTLER DL77/DL70ES/DL67 1-17

Auxiliary reagents

INSTALLATION

2. Enter the dispensing rate [mL/min] of the device. Notes: a. The titrator uses the dispensing rate to calculate the volume to be dispensed for

time-controlled pumps or electromagnetic valves (see functions Pump and Rinse, Sections 2.3.8 and 2.3.9).

b. The dispensing rate of each device must be determined experimentally in advance

for each solvent:

– Add the particular solvent using the dispensing device to a measuring cylinder

within 1 minute (stopwatch) and note the volume. – Repeat this procedure for, e.g. periods of 20, 30 and 40 seconds. – Use the different volumes to calculate the mean value per minute and enter this

value.

3. Select the auxiliary output from the selection menu. Note: The titrator has three auxiliary outputs (Aux. 1, 2 and 3). One auxiliary output of the

titrator is normally assigned to the stirrer, e.g. Aux. 1 (see Section 1.7). You should thus select only Aux. 2 and/or Aux. 3 for this auxiliary reagent (see

Technical data

, Section

11.2.2). If you have attached the sample changer (ST20A or ST20), this unit offers you two additional outputs called "RINSE" and "DOSE".

The auxiliary reagent with the modified parameters is installed when you quit the parameter mask with EXIT (see the appropriate description at the end of Section 1.1.2).

1.4.3 Add

Select this command when you wish to add an auxiliary reagent to the list. You can also add an auxiliary reagent directly to the list by pressing the <+> (plus) key. You are always shown the following mask:

Name H2O Dispensing rate [mL/min] 250 Auxiliary output Aux.2

1. Select the name from the recommendation menu or enter the reagent you wish to install. Note: If you install several auxiliary reagents with the same name, you must provide each one

with a different flag to allow the titrator to distinguish between them, e.g. H2O/2.

2. Enter the dispensing rate [mL/min] of the device.

1-18

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Auxiliary reagents

3. Select the auxiliary output from the selection menu.

The auxiliary reagent with the appropriate parameters is installed when you quit the parameter mask with EXIT (see the appropriate description at the end of Section 1.1.2).

Menu tree

Auxiliary reagents H

CHCl

250 mL/min 250 mL/min 250 mL/min

etc.

Aux. 2 Aux. 2 Aux. 2

Auxiliary reagent parameters Name Dispensing rate [mL/min] Auxiliary output

Enter new name or select entry from recommendation menu with SEL

Enter new dispensing rate

250 Aux. 2

Selection Delete Modify Add

Reagent names

CHCl

etc.

The auxiliary reagent is deleted

Select another auxiliary output with SEL

Aux/reagent Aux. 1 Aux. 2 Aux. 3 ST20 DOSE ST20 RINSE

02/93 METTLER DL77/DL70ES/DL67 1-19

Auxiliary instruments

INSTALLATION

1.5 Auxiliary instruments

When you select this menu you are shown the installed auxiliary units with the specified parameter auxiliary output. Auxiliary instruments can be pumps, dispensers, valves or relays that have a 24 V connector. They are controlled by the titrator; the actual function of the units is unknown to the titrator.

Pump Aux.3 Dispenser Aux.3 Valve Aux.3

If you select pump, for instance, the list is masked on the right by a selection menu containing the following commands:

Delete Modify Add

1.5.1 Delete

Position the selector bar on this command and confirm with RUN. The mask of the selection menu disappears, the auxiliary unit pump is deleted.

Note: You can also delete an auxiliary instrument directly from the list by pressing the

<–> (minus) key. You can reinstall "Pump" with the command Add (see Section 1.5.3).

1.5.2 Modify

If you select this command you are shown the parameter mask of the auxiliary instrument in which you can change the parameter values:

Name Pump Auxiliary output Aux.3

1. Select the name from the recommendation menu or enter the name of the device you wish to install in place of the pump.

2. Select the auxiliary output from the selection menu.

Note: If you have attached the sample changer (ST20A or ST20) this unit offers you an addi-

tional auxiliary output called "DISPENSER" (a relay make contact), see note in Section

1.4.2.

1-20

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Auxiliary instruments

The auxiliary instrument with the modified parameters is installed when you quit the parameter mask with EXIT (see the appropriate description at the end of Section 1.1.2).

Menu tree

Auxiliary instruments Pump Dispenser Valve

•

Aux. 3 Aux. 3 Aux. 3

Auxiliary instrument parameters Name Auxiliary output

Enter new name or select entry from recommendation menu with SEL

Select another auxiliary output with SEL

Pump Aux. 3

Selection Delete Modify Add

Instrument names Pump Dispenser Valve

Aux/instrument Aux. 1 Aux. 2 Aux. 3 ST20 DOSE ST20 RINSE ST20 DISPENSER

The auxiliary instrument is deleted

1.5.3 Add

Select this command when you wish to add an auxiliary instrument to the list. You can also add an auxiliary instrument directly to the list by pressing the <+> (plus) key. You are always shown the following mask:

Name Auxiliary output Aux.3

1. Select the name from the recommendation menu or enter the name of the device you wish to install.

02/93 METTLER DL77/DL70ES/DL67 1-21

Auxiliary instruments

INSTALLATION

Note: If you install several auxiliary instruments with the same name, you must provide each

one with a different flag to allow the titrator to distinguish between them, e.g. Pump/2.

2. Select the auxiliary output from the selection menu.

The auxiliary instrument with the appropriate parameters is installed when you quit the parameter mask with EXIT (see the appropriate description at the end of Section 1.1.2).

1-22

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Auxiliary values

1.6 Auxiliary values

When you select this menu you are shown 20 auxiliary value memories: H1 - H20. You can assign results of a titration such as blank values and potentials to these memories using the Auxiliary value function. These are then entered automatically here together with the date (see Section 2.3.15).

Auxiliary value 1 = H1, Auxiliary value 2 = H2, etc.. You can also enter numeric values here as an auxiliary value and you can then call up these

under different functions. As auxiliary value H1 the ZnSO4 solution with the concentration of 0.1 mol/L is stored that is

used as volumetric solution for the titer determination of EDTA (see METTLER method M007, Section 10).

H1 c(ZnSO4) 0.1 H2 1.0 etc.

You can neither delete H1 to H20 nor add "H21" to the list. If you select H1, for instance, you are shown the following parameter mask:

Auxiliary value H1 ID-text c(ZnSO4) Value 0.1 Date/time 00–00–0000 00:00

1. You can not change the name H1: The line will be skipped when the selector bar is moved.

2. Modify eventually the identification text.

3. Modify the value (do not modify it, if you use method M007!).

4. You can not enter the date. It refers to the determination of the auxiliary value using the method function

Auxiliary value

and is entered here together with the time automatically

(see Section 2.3.15).

Notes: a. You can delete the data of an auxiliary value only by overwriting it or letting the

titrator overwrite it through the

Auxiliary value

function.

b. You receive no warning from the titrator if you overwrite an auxiliary value. If you

make full use of the auxiliary value memory you should print out a list of its values occasionally (see Section 5.1.2).

c. If you modify an auxiliary value parameter, the date/time is deleted.

02/93 METTLER DL77/DL70ES/DL67 1-23

Auxiliary values

INSTALLATION

The auxiliary value with the modified parameters is installed when you quit the parameter mask with EXIT (see the appropriate description at the end of Section 1.1.2).

Menu tree

Auxiliary values H1 H2 H3

c(ZnSO

1.0

etc.

Auxiliary value parameters

)

0.1

Auxiliary value ID text Value Date/time

The name cannot be changed

Enter new ID-Text or let it be entered through titration

Enter new value or let it be entered through titration

Date/time is entered only through titration by the titrator by means of the method function

H1 c(ZnSO

0.1 00-00-0000 00:00

Auxiiliary value

)

1-24

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Titration stands

1.7 Titration stands

When you select this menu you are shown the names of six possible titration stands with the specified parameters stirrer connection and default speed. The names of the titration stands are permanently installed, in other words you can not modify them.

Stand 1 Aux. 1 50 Stand 2 Aux. 1 50 ST20 1 Aux. 1 50 ST20 2 Aux. 1 50 Free stand Aux. 1 50 Auto stand Aux. 1 50

Stand 1 is the titration stand you receive with the standard equipment of the titrator.

The associated stirrer is installed at auxiliary output Aux. 1.

Stand 2 is the second titration stand of a dual titration stand. The associated stirrer

is installed at auxiliary output Aux. 1.

ST20 1 is the first sample changer titration stand. The associated stirrer is installed

at auxiliary output Aux.1.

ST20 2 is the second sample changer titration stand. The associated stirrer is in-

stalled at auxiliary output Aux.1.

Free stand is a titration stand that you have set up independently of the titration stands

mentioned, e.g. if you attach a stirrer to a stand. The associated stirrer is installed at auxiliary output Aux. 1.

Auto stand is the name of the titration stand at which you can run a sample series with-

out ever being asked to insert the next sample (see Section 3.1.3). The associated stirrer is installed at auxiliary output Aux.1. With this stand you can, for example, use a robot to change the samples.

DL70ES/DL67: "ST20 2" is not listed, as you can not connect a second sample changer. DL77: When two sample changers are connected, one must be a ST20A (see Sec-

tion 1.8.4).

02/93 METTLER DL77/DL70ES/DL67 1-25

Titration stands

INSTALLATION

You can neither delete a titration stand nor add a new one to the list. If you select Stand 1, for instance, you are shown the following parameter mask:

Name Stand 1 Stirrer connection Aux.1 Default speed [%] 50 Conditioning mode Fix

1. You can not change the name of the titration stand: The line is skipped when the selector bar is moved.

2. From the selection menu select the stirrer connection to which you wish to attach the stirrer for titration stand 1.

If you stir with a stirrer that is not attached to the titrator, select here Not to DL: The waiting times specified under the Stir function are always adhered to within the method. However, you yourself are responsible for the stirring (see

Stir

function, Section 2.3.3).

3. Enter the default speed [0-100%] of the stirrer:

• 0 –> the stirrer is inactive;

• 100 –> the stirrer operates at maximum speed.

4. Select the type of conditioning for the

Conditioning

function: "Fix" or "Flexible" (pertains

only to stand ST20 1 or ST20 2). Fix: The ST20A (ST20) conditions with the parameters designated in the

Conditioning

function (see Section 2.3.10).

Flexible: The ST20A (ST20) conditions every time it finds a conditioning beaker on the

turntable.

Note: The titration stand in use is always recorded.

1-26

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Menu tree

Titration stands Stand 1 Stand 2 ST20 1 ST20 2 Free stand Auto stand

Aux. 1 Aux. 1 Aux. 1 Aux. 1 Aux. 1 Aux. 1

50 50 50 50 50 50

Titration stand parameters Name Stirrer connection Default speed [%] Conditioning mode

Titration stands

Stand 1 Aux. 1 50 Fix

The name cannot be changed

Select another output with SEL

Enter new default speed

Select other conditoning mode with SEL: Flexible

Aux/titrn stand Aux. 1 Aux. 2 Aux. 3 Not to DL

02/93 METTLER DL77/DL70ES/DL67 1-27

Peripherals

INSTALLATION

1.8 Peripherals

When you select this menu you are shown the names of the units you can attach to the titrator via the RS232C or CL interface. When you receive the titrator no unit is installed.

Printer Not installed Balance Not installed System Not installed Sample changer Not installed

1.8.1 Printer

If you wish to attach a printer you have to install it. Select Printer and you are shown the following parameter mask:

Status Not installed Printer type LX800 Paper Fanfold Paper format 81/

11" Automatic form feed No Frame lines Straight Baud rate 2400 Parity Even Number data bits 8 bits Number stop bits 1 stop bit

1. Select the status with SEL: "Not installed" or "Installed".

2. Select the printer type from the selection menu:

• LX800 (EPSON ESC/P command language)

• HP Deskjet (HP PCL III command language)

• DICONIX 180si (extended IBM Proprinter command language)

• IBM (IBM Proprinter command language)

• Diabolo 630 (ASCII characters).

3. Select the paper with SEL: "Fanfold" or "Single sheet".

• Single sheet: - A form feed is forced at the end of a page.

- If you select Yes for "Automatic form feed" (see Parameter 5), a header and a footer will be printed on each page of the record.

1-28

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Peripherals

Caution: Do not activate the printer's line feed or form feed functions if you have selected

"Automatic form feed" for the "Single sheet" paper mode! On the titrator the following key combinations will activate the printer functions:

<index + L> causes a line feed, <index + P> causes a form feed.

4. Select the paper format from the selection menu:

• DIN A4 (width = 21 cm, length = 29,7 cm)

•81/2 * 11" (width = 81/2 inches, length

•81/2 * 12" (width = 81/2 inches, length

11 inches)

12 inches)

5. Select the automatic form feed with SEL: "Yes" or "No".

• Yes: The printer inserts a form feed at the end of each document.

• No: Each document is separated from the next by a space of 2 lines.

6. Select the frame lines for the record from the selection menu:

• Straight: The printout will be framed with continuous lines.

• Dotted: The printout will be framed with dashed lines; the printing proceeds at twice the previous rate.

• None (no frame): Printing proceeds fastest with this parameter.

7. Select the baud rate from the selection menu:

• 1200

• 2400

• 4800

• 9600.

8. Select the parity from the selection menu:

• Even

• Odd

• None.

9. Select the data bits with SEL: "8 bits" or "7 bits".

10. Select the stop bits with SEL: "1 stop bit" or "2 stop bits". Attach the printer to the data output with the designation "Printer". The connection cable is part

of the standard equipment of the titrator (see Section 11.3:

02/93 METTLER DL77/DL70ES/DL67 1-29

Accessories

Peripherals

INSTALLATION

1.8.2 Balance

If you wish to attach a balance you have to install it. Select Balance and you are shown the following parameter:

Transmission mode Select from the selection menu

• Unidirectional

• Bidirectional

• Not installed

• Unidirectional: In the case of the weight request the balance transfers the current weight value (without stability detector) continuously and this is displayed by the titrator. You must confirm this display with RUN for the value to be accepted.

Data to titrator

Balance

Configuration: "Send Cont."Titrator

• Bidirectional: In the case of the weight request the balance transfers the current weight value when the titrator requests it and this value is then displayed by the titrator (with stability detector).

On AM, PM and AT balances the weight limits are superimposed on the balance display (see Section 3.1.1).

The titrator accepts the weight value when you press either the RUN or the transfer key of the balance.

Command from titrator

Titrator

Balance

Data to Titrator

Configuration: "Send Stable"

("Send on Transfer")

Note: a. You can attach every METTLER balance fitted with a CL interface. The data output

of the attached balance must be configured as follows:

• Baud rate: 2400

• Parity: even

1-30

• Operating mode: "Send Cont." for unidirectional transmission mode "Send Stable" ("Send on Transfer") for bidirectional transmission mode.

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Notes: b. With AT balances, the following settings are important:

• Unit: Prt on print/transfer command on g balance unit in g

• Int-FACE: SENd S.Stb transmission mode: standby

bd 2400 baud rate: 2400 PAr -E- parity: even HS OFF handshake (XON/XOFF) off

c. With AB, PB and PR balances, the LC-CL cable must be configured as follows:

• Left switch: position 7

• Middle switch: position 3

• Right switch: position 4

d. You can also attach SARTORIUS balances with the converter cable RS-CL/

CL-RS (see

Accessories

, Section 11.3); for this you must select Bidirectional as

the transmission mode. We have tested the following balances:

Peripherals

• BA 3100 P

• E 12000 S

• A 200 S

• MC1 LC 220 S

• MC1 RC 210 P

The data output of the attached balances must be configured as follows:

• Data output: ext. print command / irrespective of stability

• Baud rate: 2400

• Parity: even

• Stop bit: 1

• Weight unit: g

12/93

02/93 METTLER DL77/DL70ES/DL67 1-31

Peripherals

INSTALLATION

1.8.3 System

If you wish to attach a terminal or a computer you must first install these devices. Select System and you are shown the following parameters:

Instrument type Not installed Baud rate 4800 Parity Even Number data bits 8 bits Number stop bits 1 stop bit

1. Select the instrument type from the selection menu:

• Color terminal

• Monochrome term.

• Computer

• Not installed.

2. Select the baud rate from the selection menu:

• 1200

• 2400

• 4800

• 9600.

3. Select the parity from the selection menu:

• Even

• Odd

• None.

4. Select the number of data bits with SEL: "7 bits" or "8 bits".

5. Select the number of stop bits with SEL: "1 stop bit" or "2 stop bits".

Terminal

You can use a terminal of the type DEC VT340 or DEC VT241 as a color terminal. As a B/W terminal a DEC VT330 or DEC VT240 terminal can be used. The cable with order number 201507 can be used as connection cable (see Section 11.3:

Accessories

The terminal should be configured as follows:

• Baud rate: 4800 or 9600 baud

• Parity: even

• Number data bits: 8

• Number stop bits: 1

1-32

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Peripherals

You will find additional information regarding configuration of the terminal and keyboard operation in Section 7.2.

Computer

The computer requires an RS232C interface (DTE). The baud rate, parity, number of data bits and number of stop bits are freely selectable. The cables with order numbers 201507 (25 pin) or 201508 (9 pin) can be used as connection cable (see Section 11.3:

Accessories

If you have installed a computer, you must confirm the line "Instrument type ... Computer" with RUN to define the following parameters:

Character set Select the relevant parameter value with SEL: "ASCII" or "DL".

ASCII: The standard character set (HEX 20 to HEX 7E) for text output

to the computer is used.

DL: The character set in the titrator is used. Caution: If you select DL, you must define 8 for the number of data

bits!

Send mode Select the relevant parameter value with SEL: "Spontaneous" or "On

request". Spontaneous: The titrator sends the computer requests and data as

soon as they are generated (assumes that the computer is ready). On request: The titrator awaits the appropriate inquiry from the com-

puter before sending a request or data.

Communication Select the relevant parameter value with SEL: "Normal" or "Reduced". protocol

Normal: The data received either by the titrator or the computer will be checked and errors found will be announced with error messages (safety mechanism active).

Reduced: Data received will neither be checked nor acknowledged, consequently no error messages will be sent (safety mechanism inactive).

Start/end Select the relevant parameter value with SEL: "{/<CR>" or "<STX>/ characters

<ETX>". These start of text and end of text characters for telegrams to be sent depend on the input possibilities of your computer.

You will find additional information regarding communication between the titrator and the computer in Section 7.1 and in the Operating Instructions provided with the RS option.

02/93 METTLER DL77/DL70ES/DL67 1-33

Peripherals

Peripherals: Menu tree for system with computer

Peripherals Printer Balance System Sample changer

System parameter Instrument type Baud rate Parity Number data bits Number stop bits

Select instrument type with SEL

System parameters Instrument type Baud rate Parity Number data bits Number stop bits

Not installed Not installed Not installed Not installed

Not installed 4800 Even 8 bits 1 stop bit

Instrument type Color terminal Monochrome term. Computer Not installed

Computer 4800 Even 8 bits 1 stop bit

Select another baud rate with SEL

Select another parity with SEL

Select "7 bits" with SEL

Select "2 stop bits" with SEL

INSTALLATION

Baud rate system 1200 2400 4800 9600

Parity Even Odd None

Computer Character set Send mode Communication protocol Start/end characters

Select "DL" with SEL

Select "On request" with SEL

Select "Reduced" with SEL

Select "{/<CR>" with SEL

1-34

ASCII Spontaneous Normal <STX>/<ETX>

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Peripherals

1.8.4 Sample changer If you wish to attach the sample changer (ST20A or ST20) you have to install it. Select Sample

changer and you are shown the following parameter: Status Select the relevant parameter with SEL: "Not installed" or "Installed".

DL77: This titrator can control two sample changers (see Section 1.7:

1" and "ST20 2"). The condition for this is that you must use at least one new sample changer, the ST20A (ST20 is the name of the older model).

The second sample changer is connected to the first with the "dublex cable ST20A". You can designate the two sample changers ("ST20 1" und "ST20 2") using the identification switch of the ST20A (see the ST20A installation instructions).

Two sample changers can be used for

• parallel titrations of a sample series on each of the sample changers (Analysis A and Analysis B, see Section 3.14).

• successive determinations of sample series with a total of 40 samples ("unattended"). The conditions for this are described in Section 3.15.

Connection scheme for 2 sample changers

Duplex cable ST20A to ST20/ST20A

Connection cable ST20/ST20A

Titration stands

"ST20

Titrator

ST20 or ST20A

02/93 METTLER DL77/DL70ES/DL67 1-35

ST20A

Miscellaneous

INSTALLATION

1.9 Miscellaneous

When you select this menu you are shown the various submenus and parameters whose values or names you can or must select or specify:

Date/time format Enter date/time Language Record header Titrator ID Routine level Audio signal Analysis parameters

1.9.1 Date/time format

You are offered several ways to write the date and time. If you wish to modify the existing formats, select this parameter and you are shown the following parameters:

Date format Select the new format from the selection menu. Time format Select the other format with SEL.

Note: If you modify the format after one month, for example, the new format will be adopted

for all previously stored data.

1.9.2 Enter date/time

In the course of time you may possibly need to reset the dates. When you select this line you are shown the following parameters:

Day Enter the appropriate data. Month Year Hour Minute

1-36

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Miscellaneous

1.9.3 Language

The titrator understands and outputs English, German, French, Italian, and Spanish. Select this parameter if you wish to change the current language and you are shown the following parameter:

Active language Select the new language from the selection menu.

1.9.4 Record header

Select this parameter if you wish to enter a text that should appear on every record of a titration method. You are shown the following parameter mask:

Text: You have these two lines available for entry. Text:

1.9.5 Titrator ID

Select this parameter if you wish to enter an identification for your titrator – it will appear in every record header. You are shown the following parameter:

Titrator ID Enter an identification.

02/93 METTLER DL77/DL70ES/DL67 1-37

Miscellaneous

INSTALLATION

1.9.6 Routine level

With the aid of this menu you set up a precondition that determines whether all people who work with the titrator should also have access to the main menus, in other words be allowed to delete installation data or modify methods. If, for example, you have temporary staff who can perform only routine analyses, it is practical to "block" their access to several menus. When the titrator is delivered you have access to all menus, they are "open". To change this situation, select Routine level. You are shown the following parameter mask:

Installation "Open": The user has access to this menu. If he should

not access it, press SEL: → "Blocked".

Editor "Open": The user is allowed to develop, modify, delete,

and print out methods in the Editor menu. If he should be allowed to only print out the stored methods

press SEL: → "Blocked".

Documentation "Open": The user has access to this menu. If he should

not access it, press SEL: → "Blocked".

Analysis: Modify parameters "Open": The user is allowed to modify the parameters

of the current method in the Analysis menu. If he should not be allowed to do so,

press SEL: → "Blocked".

When you now select Routine in the USER LEVEL menu the user no longer has access to the menus blocked here (see Section 6).

1-38

METTLER DL77/DL70ES/DL67

02/93

INSTALLATION

Miscellaneous

1.9.7 Audio signal

An audio signal either confirms each keystroke or draws your attention to instructions, directions or error messages. In the factory setting of the titrator, all these parameters are signalled. When you select this menu you are shown the following parameter mask:

Keystroke "Yes": You hear a brief signal after every keystroke. If you do not

wish to hear this, press SEL: → "No".

Results "Yes": You hear a brief signal after every result that appears on the

display. If you do not wish to hear this, press SEL: → "No".

Messages "Yes": Your attention is drawn to error messages, directions and

instructions by a signal. If you do not wish to hear this, press SEL: → "No".

Notes: a. Error messages: You must confirm each error message with RUN and rectify the

error. Otherwise the titrator will not continue with the desired operation.

b. Instructions: Your current method includes the function Instruction under which

you have entered a text. You must confirm this with RUN before the titrator can continue operation (see Section 2.3.6).

c. Directions: During the sequence of a method the titrator will give you directions that

you must confirm with RUN before it can continue operation.

02/93 METTLER DL77/DL70ES/DL67 1-39

Miscellaneous

INSTALLATION

1.9.8 Analysis parameters

During the course of a titration method, certain information, which must be confirmed with RUN for the titration to proceed, will appear on the display:

• Initially the mask "Installed are" (see Section 3.1).

• After the titration the mask "Results of this sample" (see Section 3.1.3). These two masks can be excluded to accelerate the titration course. If you select this menu,

you are shown the following parameter mask:

Installation data "Yes": The mask "Installed are" appears prior to titration of

each sample. Should this not happen, press SEL: → "No".

Results last sample The mask "Results of this sample" appears after titration of

each sample. Should this not happen, press SEL: → "No".

1-40

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Contents Page

2. EDITOR ....................................................................................................... 2-3

2.1 Select methods .......................................................................................... 2-5

2.1.1 Print ............................................................................................................. 2-6

2.1.2 Delete .......................................................................................................... 2-7

2.1.3 Modify .......................................................................................................... 2-7

2.2 Select functions ......................................................................................... 2-8

2.2.1 Cut ............................................................................................................... 2-8

2.2.2 Copy ............................................................................................................ 2-8

2.2.3 Paste............................................................................................................ 2-8

2.2.4 Add .............................................................................................................. 2-9

2.2.5 Modify .......................................................................................................... 2-10

2.2.6 Save method................................................................................................ 2-11

2.3 Functions.................................................................................................... 2-14

2.3.1 Title .............................................................................................................. 2-14

2.3.2 Sample......................................................................................................... 2-15

2.3.3 Stir ............................................................................................................... 2-18

2.3.4 Measure....................................................................................................... 2-20

2.3.5 Temperature ................................................................................................ 2-22

2.3.6 Instruction .................................................................................................... 2-23

2.3.7 Dispense...................................................................................................... 2-24

2.3.8 Pump ........................................................................................................... 2-25

2.3.9 Rinse............................................................................................................ 2-26

2.3.10 Conditioning................................................................................................. 2-27

2.3.11 Auxiliary instrument ..................................................................................... 2-31

2.3.12 Titration........................................................................................................ 2-32

2.3.12.1 DOS (Titration mode: dispensing) ............................................................... 2-34

02/93 METTLER DL77/DL70ES/DL67 2-1

EDITOR

Page

2.3.12.2 EQP (Titration mode: equivalence point determination) .............................. 2-36

Predispensing .............................................................................................. 2-39

DYN (Titrant addition) .................................................................................. 2-40

INC ((Titrant addition) .................................................................................. 2-41

EQU (Measure mode).................................................................................. 2-42

TFIX (Measure mode).................................................................................. 2-44

Threshold (Equivalence point recognition) .................................................. 2-45

EQP range (Equivalence point recognition)................................................. 2-49

Termination criteria ...................................................................................... 2-51

Evaluation criteria ........................................................................................ 2-51

2.3.12.3 EP (Titration mode: end point determination) .............................................. 2-53

Predispensing .............................................................................................. 2-53

Continuous (Titrant addition) ....................................................................... 2-54

Dynamic (Titrant addition)............................................................................ 2-55

End point mode............................................................................................ 2-56

Tendency ..................................................................................................... 2-57

Maximum volume......................................................................................... 2-57

2.3.12.4 LEARN EQP (Learn titration: equivalence point determination) .................. 2-58

2.3.12.5 LEARN EP (Learn titration: end point determination) .................................. 2-60

2.3.13 pH/mV-stat................................................................................................... 2-62

2.3.14 Calculation................................................................................................... 2-66

2.3.15 Auxiliary value.............................................................................................. 2-70

2.3.16 Titer.............................................................................................................. 2-71

2.3.17 Calibration.................................................................................................... 2-72

2.3.18 Statistics ...................................................................................................... 2-75

2.3.19 Record ......................................................................................................... 2-77

2.3.20 Sync............................................................................................................. 2-81

2-2

METTLER DL77/DL70ES/DL67

02/93

EDITOR

2. EDITOR

In this menu you develop titration methods, which you can store. You can modify or delete these methods or print them out.

A complete titration method comprises sample preparation, dispensing of auxiliary solutions, stirring and waiting times, the titration itself, calculation of the result and statistics and a record. In the titrator these substages are defined as functions that are executed in succession in an analysis. Within a method you can not only modify these functions, but also cut them out of the defined sequence and hence delete them or paste them in at a different place. You can also add a new function to a method. Virtually all functions can occur more than once in a method (see Section 8.5.1).

List of all functions: Title

Sample Stir Measure Temperature Instruction Dispense Pump Rinse Conditioning Auxiliary instrument Titration pH/mV-stat Calculation Auxiliary value Titer Calibration Statistics Record Sync

02/93 METTLER DL77/DL70ES/DL67 2-3

EDITOR

The individual functions comprise parameters whose values or names can be modified.

When you develop a new method you are always shown the standard method with default parameters, which you can then modify to suit your needs (see:

New Method,

Section 2.1).

Method

print delete modify

Function

cut copy paste add modify

modify

Parameter

You modify a method by changing its functions.

You modify a function by changing its parameters.

You will find the representation of the Editor menu tree at the end of Section 2.2.

2-4

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Select methods

2.1 Select methods

You are shown the following submenu in the Editor menu:

Method ID METTLER methods User methods

New method

Under method ID you can call up all stored methods, under METTLER methods only those in the application data base, and under user methods only those methods available in the user data memory.

Method ID

The method identification is a 4-character, alphanumeric identifier of a method. If you know it, select Method ID (see

Title

function, Section 2.3.1).

Enter the method ID and confirm with RUN. The entry will be masked by the following selection menu:

Print (Delete) appears only after ID entry of a user method

Modify

Note: It is possible to enter an asterisk (∗) or a question mark (?) after the first, second or

third letters/numbers of the method ID:

∗: replaces all subsequent letters/numbers. For example, x∗: results in the display of

all methods with an ID beginning with this letter or number.

?: replaces one letter or number within the ID. For example, xy?z will result in the

display of all methods with an ID containing these three letters/numbers.

METTLER methods

When you select this option you receive a list of all methods stored in the application data base with the identification and the name of the method:

M001 Acid content M002 Titer of NaOH (0.1 mol/L) etc.

If you select M001, for instance, the method is masked on the right by the following selection menu:

Print Modify

02/93 METTLER DL77/DL70ES/DL67 2-5

Select methods

EDITOR

User methods

If you select this, you are shown a list of methods with the identification and name of the method if you yourself have stored a method in the user data memory, e.g.

KM59 pH–stat of Gerusil UB33 H3PO4 in cola drinks

If you then select a method, it is masked on the right by the following selection menu:

Print Delete

Modify

New Method

If you wish to develop a new method, select New Method. You are shown the standard method with the following functions:

Title Sample Stir Titration Calculation Statistics Record

All parameters of the functions – except those of the Title function – are defined with default values or names. You can accept or modify these; you can also add additional functions to this standard method (see Sections 2.2.3 and 2.2.4).

Note: To set up a method with more than the standard functions, you will find the scheme in

Section 8.8 useful. You can copy this scheme and use it to design the method, which you can then enter in this menu.

2.1.1 Print

– Position the selector bar on this command and confirm with RUN. The method together with its functions and the corresponding parameter values will be printed

out on an attached printer.

2-6

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Select methods

2.1.2 Delete

– Position the selector bar on this command and confirm with RUN. In the selection menu "Delete method" you can confirm or cancel the selection: – Yes: The method is deleted. – No: The method remains stored.

Notes: a. METTLER methods can not be deleted.

b. If a user method is entered in the method list of the Analysis menu and not yet

executed, the message "Method is blocked" appears (see also Note c. in the next section).

2.1.3 Modify

When you select this command you receive a list with all functions included in this titration method, e.g.

Title Sample Measure Dispense Stir Titration Calculation Record

Notes: a. You can modify METTLER methods to match your requirements, but you must then

provide them with a new method identification under the Title function in order to save them (see Section 2.3.1).

b. If you modify a user method or simply wish to copy it and keep the original, you must

give it a new method identification under the Title function (see Section 2.3.1).

c. If you select a user method that is entered in the method list of the Analysis menu

and not yet executed, the message "Method is blocked" appears. To modify this method, you have to give it a new method identification under the Title function. The method in the method list remains unchanged (see Sections 3.1 and 3.13).

02/93 METTLER DL77/DL70ES/DL67 2-7

Select functions

EDITOR

2.2 Select functions

When you select the Title function, you are shown this selection menu on the right of the display:

Modify

You can only modify the Title function since the storage and call options require that it is always first in the sequence of functions.

If you select the Measure function you are shown the following selection menu on the right of the display.

Cut Copy Paste Add

Modify

2.2.1 Cut

– Position the selector bar on the command and confirm with RUN. (You can also cut a

function directly from the list by pressing the <–> (minus) key.) The Measure function is deleted at this location. However, it is stored in a buffer memory so that you can paste it in elsewhere if appropriate

(see Section 2.2.3). The function remains stored until you either cut or modify another function.

2.2.2 Copy

If you merely wish to copy the Measure function in order to paste it in elsewhere, – position the selector bar on this command and confirm with RUN. The Measure function remains at this location and is also stored in a buffer memory so that

it can be pasted in elsewhere. The function remains stored until you either cut or modify another function.

2.2.3 Paste

You now wish to paste in the cut (or copied) Measure function before the Stir function: – Position the selector bar on the Stir function and press the <=> (equals) key.

2-8

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Select functions

The Measure function now follows the Dispense function:

Title Sample Dispense Measure Stir Titration Calculation Record

You can paste a function only if you have first cut or copied it. Since the Measure function is still stored, you can also paste it in ahead of the Titration function, for instance.

2.2.4 Add You would like to add the Auxiliary value function to the method, in this case before the

Record function:

– Position the selector bar on the Record function and press the <+> (plus) key. You are now

shown a list of all functions (except

Title

function). – Position the selector bar on the Auxiliary value function and confirm with RUN. The Auxiliary value function now follows the Calculation function:

Title Sample Dispense Measure Stir Titration Calculation Auxiliary value Record

Note: If you select an improper sequence when pasting or adding the functions, the titrator

sends you an error message (e.g. you can not place the Statistics function before the Calculation function). However, the error message is not outputted until the method is saved.

02/93 METTLER DL77/DL70ES/DL67 2-9

Modify functions

EDITOR

2.2.5 Modify

This command shows you a mask with the parameters needed for the function. You can modify the values or names of these parameters.

Notes: a. The parameters of all functions – except those of the Title function – are defined

by default values or names. These are overwritten as soon as you enter a new value or name. If you wish to correct a parameter, indicate the appropriate letter (number) with the cursor (with → or ←), then enter the new one. With SEL, other parameters may be selected from the recommendation or selection menus (see Section 1.1.2).

b. The method identification, formulae and conditions are checked immediatly after

their entry. If they are incorrect, an error message appears, such as:

Error No.3 Wrong formula Modify Terminate

If you confirm "Modify" with RUN, you can change the entry. If you confirm "Terminate" with RUN, the most recently saved prior entry appears.

c. As soon as you quit a parameter mask with EXIT the values or names are stored.

The selector bar must be located on a parameter here. If you confirm the title line of a parameter mask with EXIT, the following mask appears:

Save modifications?

Yes No

If you confirm "Yes" with RUN, the titrator stores the changed values or names. If you confirm "No" with RUN, the old remain stored. The display then shows either the method functions or the master parameter mask.

d. If you press a key combination (<index + letter>) to quit the Editor menu, the

following selection menu appears:

Save?

Yes No

2-10

If you confirm "Yes" with RUN, the titrator stores the changed method. If you confirm "No" with RUN, the old values remain stored.

e. If you do not wish to modify the parameters of a function, after you have checked

them, quit the mask with Exit. The location of the selector bar is immaterial here. The values of this function remain stored.

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Save method

2.2.6 Save method

After modification of each function you can save your method. – Press EXIT, regardless of the current position of the selector bar. The selection menu

"Save"? appears: No: Confirm with RUN: The method with the modified parameters is not saved, the old

version is retained.

Yes: Confirm with RUN: The titrator now checks the method and, if several errors are

present, draws your attention to the first one.

– Confirm these messages with RUN in each case. a. You are shown the list of the method functions with the selector bar on the first incorrect

function. After you have corrected its parameters and saved the method once more (see above) you are shown the next incorrect function, etc.

b. If you have entered a method identification under the Title function that already exists,

the selection menu "ID exists" appears: Overwrite ID: Confirm with RUN: The new or modified method is saved, that with

the same identification is deleted.

Modify ID: Confirm with RUN: You are shown a list of the method functions and

can modify the method ID using the Title function. Then you can save the method (see above).

If you are not shown any error message when you confirm "Save?" with Yes, the list of user methods with the stored method appears in the display.

Note: If you press a key combination (<index + letter>) in the function list to quit the Editor

menu, the selection menu "Save?" always appears first.

02/93 METTLER DL77/DL70ES/DL67 2-11

Menu tree

EDITOR: Menu tree

EDITOR

Method ID

Method ID GR41

Method Print Delete Modify

Modify method Title GR41 Sample etc.

METTLER methods

METTLER methods M001 Acid content M002 Titer of NaOH (0.1 mol/L) etc.

Method Print Modify

Modify method Title M001 Sample Stir Titration Calculation Calculation Calculation Calculation Record Statistics Record

User methods

User methods KM59 pH-stat of Gerusil UB33 H

in Cola drinks

3PO4

etc.

Method Print Delete Modify

Modify method Title KM59 Sample etc.

New method

New method Title Sample Stir Titration Calculation Statistics Record

Function Modify

Title Method ID M001 Title Acid content Date/time 31-08-1992 13.40

2-12

Function Cut Copy Paste Add Modify

METTLER DL77/DL70ES/DL67

Sample Number samples Titration stand Entry type ID1 Molar mass M Equivalent number z Temperature sensor

2 Stand 1 Volume U HCl

36.46 1 Manual

02/93

EDITOR

Menu tree

EDITOR: Menu tree – the way back

The method/function is saved The method is not saved

Method ID

Method ID GR41

RUN RUN RUN RUN

Save?

Yes

METTLER methods

METTLER methods M001 Acid content M002 Titer of NaOH (0.1 mol/L) etc.

Save?

Yes

User methods

User methods KM59 pH-stat of Gerusil UB33 H AE38 NaOH in regeneration bath etc.

in Cola drinks

3PO4

New method

Save?

Yes

Modify method Title GR41 Sample etc.

Save modifications?

Yes

Title Method ID AE38 Title NaOH in regeneration bath Date/time 10-10-1992 12.28

RUN

Modify method Title AE38 Sample Stir Titration Calculation Record Statistics Record

RUN

Save modifications?

Yes

Sample Number samples Titration stand Entry type ID1 Molar mass M Equivalent number z Temperature sensor

Modify method Title KM59 Sample etc.

3 Stand 1 Weight m B233/1

40.00 1 Manual

02/93 METTLER DL77/DL70ES/DL67 2-13

Title

EDITOR

2.3 Functions

All functions whose parameters you wish to modify have to be selected by the operation described under Sections 2.1 and 2.2. The following explanations of all functions and their parameters thus "take place" under the command "Modify function" (see above representation of menu tree).

2.3.1 Title

This function serves to identify the titration method. It must always be first in a method and is the only function that can occur only once in a method. You need to define its parameters. You call up the stored method in question using the method identification. The function has no significance for the progress of the titration.

1. Enter the method ID: letters and/or number, max. 4 characters, e.g. B101.

2. Enter a title for the method: e.g. "NaCl in butter".

3. Date and time are entered here automatically when you save a new or modified method. You can neither clear nor overwrite this information.

Notes: a. You must adhere to the upper case or lower case notation of the identification during

entries, otherwise the titrator outputs an error message.

b. You can not use any method identifications that start with upper case M as they are

reserved for METTLER methods.

c. Asterisks (∗) and question marks (?) are not allowed in the method identification!

2-14

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Sample

2.3.2 Sample

With the aid of this function you determine the parameters that are needed for the entry of the sample data such as weight or volume, and whether the temperature of the sample should be meaured.

Parameters of the mask: Number samples

Titration stand Entry type ID1 Molar mass M Equivalent number z Temperature sensor

1. Enter the number of samples n. You can change n before and after the start of the method (see Section 3.1). A parameter

value of n = 3, for instance, tells you that you have to titrate at least three samples, e.g. in a titer determination.

2. Select the titration stand at which you wish to determine the samples from the selection menu (see Section 1.7).

You can change the titration stand before the start of the method (see Section 3.1).

3. Select the type of entry from the selection menu: a. Weight m

– Enter the lower weight limit [g]. – Enter the upper weight limit [g].

b. Volume U

– Enter the lower volume limit [mL]. – Enter the upper volume limit [mL].

The actual weight or volume are not entered until the samples are prepared or the titrator requests the amount after the start of the method (see Section 3.1).

If you violate this specified upper or lower limit you will be given a notice.

c. Fixed volume U

– Enter the volume [mL]. You can not change this entry before the start of the method!

02/93 METTLER DL77/DL70ES/DL67 2-15

Sample

EDITOR

4. Enter an initial identification: ID1 (number or name for all samples of this Sample function).

5. Enter the molar mass M. The auxiliary value "Hj" can be entered instead of the number, provided that the molar

mass has been stored here (see Section 1.6). You can change the molar mass M before the start of the method (see Section 3.1).

6. Enter the equivalent number z. For one Sample function you can enter only one molar mass M and one equivalent num-

ber z for your calculation. If your sample contains several substances that have to be determined in the titration through equivalence points, you must enter their molar mass and equivalent number in constant C under the Calculation function (see Section 2.3.14).

7. Select the temperature sensor from the selection menu if you have attached one (see Section 1.3); if not, select "Manual". The temperature entered before starting the method will then be used during the run (see Section 3.1).

With the aid of this parameter, the temperature of the sample solution is automatically determined or acquired, respectively, before the start of the functions Measure, Titration and pH/mV-stat. The slope of the pH electrode is then corrected for the temperature in the pH value calculation (see Section 1.3:

of the temperature sensors)

Temperature sensors

and Section 4.7:

Calibration

Important

The Sample function fulfills two additional tasks within the method sequence:

1. It provides the titrator with information regarding which titration stand is used for titration.

The titration stand is linked with the stirrer connection and the default speed (see Section

1.7). As soon as the titrator has executed the Sample function, it starts to stir at the default speed.

If there is no Sample function in a method, the titrator does not stir as it has no information regarding the titration stand. (A method with the Stir function but without the Sample function can not be saved for this reason!) In this case you can enter the command to stir via the auxiliary function Stirrer (see Section

4.2).

2. For the titrator the function is the identifier for the start of a series (n > 1), in other words all functions that lie between the Title function and the Sample function will not be executed after titration of the first sample.

2-16

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Sample

The identifier for the end of a series is the Statistics function. The titrator repeats all functions within the loop Sample/Statistics n times. If the Statistics function is missing in your method, only the first sample will be titrated, i.e. n is set to 1.

TITLE

SAMPLE

STIR

TITRATION

CALCULATION

Example of a sample series performed with the standard method.

Series size

reached?

Yes

STATISTICS

RECORD

Note: You will find examples of methods in Section 8.7.

02/93 METTLER DL77/DL70ES/DL67 2-17

Stir

EDITOR

2.3.3 Stir

With the aid of this function you determine the stirring or waiting times and specify new stirring speeds.

Caution: It is essential that the Stir function is preceded by a Sample function within a method

(see

Sample

1. Enter the speed of the stirrer [%]:

• 0 –> stirrer is inactive;

• 100 –> stirrer operates at maximum speed.

2. Enter the time [s]:

• "0" means that the titrator will not wait at all,

• "10" that it will wait 10 s before it starts the next function: It then stirs at the specified speed

in each case. The running stir time is displayed.

function, page 16:

Important

3. Select a condition: – No. – Yes: Enter the condition.

Notes: a. You can set a condition for most of the functions. If this is met, the function is

executed; if it is not met the function will be skipped (see Section 8.3 and an additional example under the

Record

Functions with a condition

function, Section 2.3.19).

If you have not selected a condition the function is executed.

b. The speed you have specified applies to all following functions up to the next

Sample or Stir function.

c. However, during a titration you can change the specified speed (see Section 3.10).

Example A: If you would like to continue stirring for some time after sample addition to

dissolve a solid before the titrator starts the next function, you must add the Stir function after the Sample function.

Speed = e.g.: 60 Time = e.g.: 30.

2-18

The titrator stirs for 30 s at 60% maximum speed before it processes the next function. It continues to stir at this speed until the next Sample or Stir function.

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Stir

Example B: If you would like to wait after the sample addition before starting stirring and

before the titrator starts the next function, set Speed = 0

Time = e.g. 30. The titrator will not stir for 30 s before processing the next function. This must

be a second Stir function to ensure that the titrator starts to stir: Speed = e.g.: 70

Time = 0. The titrator stirs at 70% maximum speed and immediately begins to process the

next function (see example in Section 8.7.1).

02/93 METTLER DL77/DL70ES/DL67 2-19

Measure

EDITOR

2.3.4 Measure

You can use this function to measure the potential of a solution under defined conditions. The titrator acquires the measured value as raw result E (see notes at the end of this section). If you have selected a temperature sensor in the Sample function, the temperature of the sample solution is measured automatically before the titrator executes this function. If no sensor is attached (parameter "Manual"), the titrator adopts the temperature entered at the start of the method. The slope of the pH electrode is then corrected for the temperature in the pH value calculation (see Section 4.7:

Caution: Stirring is performed under this function only if preceded by the Sample function (see

Sample

function, page 16:

Parameters of the mask: Sensor

Calibration of the temperature sensors)

Important

Unit of meas.(urement)

∆E [mV]

∆t [s] t(min) mode t(max) [s] Condition

1. Select the sensor from the recommendation menu or enter one you have installed (see Section 1.2).

2. Select the unit of measurement: "mV" or "As installed". "As installed" refers to the unit of measurement you have specified for the sensor (see

Section 1.2.2).

3. Enter ∆E [mV]: e.g. 1.

4. Enter ∆t [s]: e.g. 2.

Note: The drift in the electrode potential must be less than ∆E/∆t (0.5 mV/s) during the period

∆t (2 s) if the potential is to be acquired as a measured value. This occurs within a defined time interval t(min) and t(max). (See representation in Section 2.3.12.2:

Titration mode EQP, Measure mode EQU).

2-20

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Measure

5. Select t(min) from the following menu: a. Fix: Enter t(min) [s]: e.g. 3.

Instead of a fixed time you can select a condition: The measured value must be greater or less than a specified set value.

b. E > (greater than) set value: Enter set value [mV, pH, …]. c. E < (less than) set value: Enter set value [mV, pH, …].

6. Enter t(max) [s]: e.g. 30.

Note: If you select 5b (5c) the titrator will start the next function only when the measured

potential E is greater (less) than the set value and the drift condition is satisfied, but at the latest after t(max).

7. Select a condition: – No. – Yes: Enter condition.

Notes: a. The

raw results (see

– print these out as such on an attached printer (see Section 2.3.19 and Section

– incorporate them in the calculation (see – save as a result if you have assigned them to the result R, e.g. R = E (see Section

b. At the end of a titration only the final results are shown on the display of the titrator,

the raw results can only be printed out.

c. The titrator stores raw results up to the titration of the next sample within a loop (see

Section 8.5.7).

Measure, Temperature, Dispense, Titration

List of designations

, Section 8.1).You can

8.1.1 for exceptions).

Examples of formulae

2.3.14).

and

pH-stat

functions generate

, Section 8.6.1).

02/93 METTLER DL77/DL70ES/DL67 2-21

Temperature

EDITOR

2.3.5 Temperature

You can use this function to measure the temperature of a solution under defined conditions. The titrator acquires the measured value as raw result T (see Note a. in Section 2.3.4).

Parameters of the mask: Sensor

Unit of meas. (urement)

∆T [°C, °F, K] ∆t [s]

t(min) mode t(max) [s] Condition

1. Select the temperature sensor from the selection menu (see Section 1.3).

2. Select the unit of measurement from the selection menu: "°C", "°F" or "K".

3. Enter ∆T [°C, °F, K]: e.g. 0.02.

4. Enter ∆t [s]: e.g. 2. Note: The temperature drift must be less than ∆T/∆t (0.01 °C/s) during the period ∆t (2 s) if

the temperature is to be acquired as a measured value. This occurs within a defined time interval t(min) and t(max).

5. Select t(min) from the following menu: a. Fix: Enter t(min) [s]: e.g. 3.

Instead of a fixed time you can select a condition: The measured value must be greater or less than a specified set value.

b. T > (greater than) set value: Enter set value [°C, °F, K]. c. T < (less than) set value: Enter set value [°C, °F, K].

6. Enter t(max) [s]: e.g. 30.

Note: If you select 5b (5c) the titrator will start the next function only when the measured

temperature is greater (less) than the set value and the drift condition is satisfied, but at the latest after t(max).

7. Select a condition: – No. – Yes: Enter condition.

2-22

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Instruction

2.3.6 Instruction

This function allows you to intervene manually in the sequence of the titration method, in other words the method is interrupted. The entered text appears at the desired position during the current method in the display and is supported audibly. The method does not continue until you confirm the instruction with RUN.

1. Enter the instruction.

2. Select a condition: – No. – Yes: Enter the condition.

02/93 METTLER DL77/DL70ES/DL67 2-23

Dispense

EDITOR

2.3.7 Dispense

With the aid of this function you dispense a specified volume of titrant with a METTLER burette. The titrator acquires the dispensed volume as the raw result VDISP [mL] or QDISP [mmol] (see

List of designations

1. Select the titrant from the recommendation menu or enter one that you have installed (see Section 1.1).

2. Enter its concentration [mol/L].

3. Enter the volume [mL]. A formula, such as "R1 + 0.5", can be entered instead of a number (R1 is the result of a

Calculation function preceding this function).

4. Select a condition: – No. – Yes: Enter the condition.

, Section 8.1 and the

Measure

function, Section 2.3.4).

Example: For a simple back titration, you can add, e.g. the Dispense function to the

standard method:

Sample

SAMPLE

You have added your sample to the titration vessel and started the titration. The titrator immediately starts to stir.

Dispense

DISPENSE

The titrator dispenses the amount of the selected titrant and acquires the raw result QDISP.

Stir

STIR

You have set a long stirring time to allow the sample to react with the titrant before the titrator starts the back titration.

Titration

TITRATION

The titrator starts the back titration with a second titrant and acquires the raw result Q (consumption of the titrant in mmol up to the equivalence point or endpoint).

CALCULATION

2-24

Calculation

The formula for the content of the sample: R = (QDISP – Q) ∗ C/m (see Section 8.6:

METTLER DL77/DL70ES/DL67

Examples of formulae

02/93

EDITOR

Pump

2.3.8 Pump

With the aid of this function you select a time-controlled pump at an auxiliary output in order to pump a specified volume of an auxiliary reagent into the titration vessel.

1. Select the auxiliary reagent from the recommendation menu or enter one you have installed (see Section 1.3)

2. Enter the volume [mL].

3. Select a condition: – No. – Yes: Enter the condition.

Notes: a. You have defined the pump speed [mL/min], which you need to determine

experimentally for each auxiliary reagent, in the Installation menu by means of the dispensing rate (see Section 1.4.2).

b. If you attach the pump tubing to the wrong connectors, you will evacuate instead

of dispensing.

02/93 METTLER DL77/DL70ES/DL67 2-25

Rinse

EDITOR

2.3.9 Rinse

You use this function only in connection with the sample changer (ST20A or ST20). This has a built-in rinsing unit that controls the attached pump for rinsing (output "RINSE" or "DOSE"). The tips of the sensors and burettes are rinsed in the middle beaker position (see

ST20A Operating Instructions

1. Select the auxiliary reagent from the recommendation menu or enter one you have installed (see Section 1.4).

2. Enter the volume [mL].

3. Select a condition: – No. – Yes: Enter the condition.

Notes: a. You have defined the rate of the rinsing process [mL/min], which you need to

determine experimentally, in the Installation menu by means of the dispensing rate parameter (see Section 1.4.2).

ST20

b. If you perform a method series on the sample changer and the titrator has titrated

the last sample of the last method, sensor and burette tip are rinsed in the middle beaker position. The sample beaker is then raised so that the sensor does not dry out, in other words it remains in the sample solution.

To prevent this, you must add a Conditioning function to the last method and position a conditioning beaker after the final sample beaker.

TITRATION

CALCULATION

RINSE

Series size

reached?

The Conditioning function must then be after the loop of the last method so that the titrator does not

STATISTICS

perform conditioning after every sample determination (see Section 2.3.2:

series performed with the standard method

Section 2.3.10:

Conditioning

Example of a sample

and

CONDITIONING

2-26

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Conditioning

2.3.10 Conditioning

You use this function only in connection with the sample changer (ST20A or ST20). You determine how often and how long a sensor is kept in a solution with stirring between individual samples or series to clean it or ensure its operational reliability.

1. Enter the interval (number of samples): e.g. 3.

2. Enter the time [s]: e.g. 60 → After three titrated samples conditioning is performed for 60 s. The running conditioning time is displayed.

3. Rinse: Should electrodes and burette tips be rinsed after conditioning? – No.

– Yes: Select the auxiliary reagent from the recommendation menu or enter one you have

installed (see Section 1.3). Enter the volume [mL].

Caution: If you select this parameter the beaker can overflow after some time if you have

inserted only one conditioning beaker in the turntable but condition the sensor after every sample.

4. Select a condition: – No. – Yes: Enter the condition.

Notes

When installing the sample changer titration stand you can select Fix or Flexible as conditioning mode (see Section 1.7).

Fix: The ST20A (ST20) conditions with the parameters specified in this function (see

below: Note 2).

Flexible: The ST20A (ST20) conditions whenever it finds a conditioning beaker (see below:

Note 3). When titrating, in non-aqueous media for example, this mode allows you to place additional conditioning beakers where ever necessary during the method run.

1. Conditioning samples are marked on the sample turntable by red plugs.

02/93 METTLER DL77/DL70ES/DL67 2-27

Conditioning

2. You have selected Fix as conditioning mode: a. You can follow the above example and insert and mark a beaker with the conditioning

solution after every third sample:

EDITOR

If you wish to condition the sensor on completion of a sample series, you must ensure that the number of samples can be divided by the interval number, e.g. samples = 9, interval = 3.

If, e.g. you have entered interval = 3 with 5 samples, the sensor and burette tips remain in the fifth sample solution. To prevent this, you must add an additional Conditioning function after the loop and insert a conditioning beaker after the last sample beaker (see Section 2.3.2:

b. You can insert and mark only one beaker with conditioning solution. If this does not directly

follow the third sample, the ST20A searches for this conditioning beaker by rotating backward. It then conditions the sensor for 60 s. Afterwards, the sample turntable again rotates forwards to the fourth sample.

Example of a sample series performed with the standard method

etc.

Caution: There must be no empty positions between the titration vessel of the last titrated

sample and the conditioning beaker!

etc.

2-28

METTLER DL77/DL70ES/DL67

02/93

EDITOR

If you wish to condition the sensor on completion of a sample series, always place a conditioning beaker after the last sample beaker (number of samples must be divisible by the interval number!): The ST20A sees the following conditioning beaker:

Conditioning

C C

If, e.g. you have entered interval = 3 with 5 samples, you must add an additional Conditioning function after the loop and place a conditioning beaker after the last sample

beaker:

C C

c. You have entered 4 for the interval but have erroneously placed a conditioning beaker after

the third sample beaker. The ST20A omits the conditioning beaker!

3. You have selected Flexible as conditioning mode:

a. The method has no Conditioning function: The ST20A recognizes a conditioning beaker

and conditions the sensor for 10 seconds.

b. The method has a Conditioning function with parameters such as

Interval = 4, Time = 30 s, Rinse volume = 5 mL.

• The ST20A finds a conditioning beaker after the second sample beaker. It then conditions and rinses according to the defined parameters.

• After the fourth sample beaker the ST20A must condition. If it finds no conditioning beaker, it searches for one by turning backwards (see Note 2b.). It conditions for 30 s and rinses 5 mL.

02/93 METTLER DL77/DL70ES/DL67 2-29

Conditioning

EDITOR

c. If you would like to condition at liberty during the run, but for a certain time and with a defined

rinse volume, – add a Conditioning function to the method and – set the interval to 60, for example, and set the time and rinse volume. The ST20A must not condition during the sample series if this is done. (Note: you can not

designate more than 60 samples to a method).

2-30

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Auxiliary instrument

2.3.11 Auxiliary instrument

You can use this function to control an auxiliary instrument (dispenser, relay, electromagnetic valve, etc.) that is attached to a 24 V auxiliary output of the titrator.

1. Select the name of the auxiliary instrument from the recommendation menu or enter one you have installed (see Section 1.5).

2. Enter the time [s]: It indicates how long the voltage should be applied at the auxiliary output. A formula may be entered instead of a number, for example, "H5/2" (H5 is a time increment

which has been saved as an auxiliary value, see Section 1.6).

3. Select a condition: – No. – Yes: Enter the condition.

02/93 METTLER DL77/DL70ES/DL67 2-31

Titration

EDITOR

2.3.12 Titration

Under this function you determine the mode, control and evaluation of a titration. Depending on the titration mode, the titrator acquires several measured values and volumes as raw results (see

List of designations

If you have selected a temperature sensor in the Sample function, the temperature of the sample solution is measured automatically before the titrator executes this function. If no sensor is attached (parameter "Manual"), the titrator adopts the temperature entered at the start of the method. The slope of the pH electrode is then corrected for the temperature in the pH value calculation (see Section 4.7:

Parameters of the mask: Titrant

, Section 8.1 and

Calibration of the temperature sensors)

Concentration [mol/L] Sensor Unit of meas.(urement) Titration mode

Measure

function, Section 2.3.4).

Condition

1. Select the titrant from the recommendation menu or enter one you have installed (see Section 1.1).

2. Enter its concentration [mol/L].

3. Select the sensor from the recommendation menu or enter one you have installed (see Section 1.2).

4. Select the unit of measurement: "mV" or "As installed". "As installed" refers to the unit of measurement you have specified for the sensor (see

Section 1.2.2).

5. Select the titration mode from the selection menu.

DOS (Dispensing) EQP (Equivalence point titration) EP (End point titration) LEARN EQP (Learn titration: equivalence point determination) LEARN EP (Learn titration: end point determination)

6. Select a condition: – No. – Yes: Enter the condition.

2-32

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Titration: Menu tree

Titration

Titrant

Enter name or select from recommendation menu

DOS Dispensing 1 Dispensing 2

Concentration

Enter c

Sensor

Enter name or select from recommendation menu

EQP Predispensing 1 Predispensing 2 Titrant addition Measure mode Threshold EQP range Maximum volume [mL] Termination at potential Termination after n EQPs Termination at slope Termn after nom. consumption Combined termn criteria Evaluation procedure Steepest jump only Buffer potential 1 Buffer potential 2 Stop for reevaluation

Unit of measurement

mV As installed

Titration mode

Titration mode DOS EQP EP LEARN EQP LEARN EP

EP Predispensing Titrant addition End point mode Tendency Maximum volume [mL]

Condition

Condition No Yes

Enter mL

Dispensing 1 mL % nom. content No

02/93 METTLER DL77/DL70ES/DL67 2-33

Dispensing 2 Potential Slope No

Predispensing mL % nom. content No

End point mode EPA EPR EPS

Positive Negative

Addition mode: EP Continuous Dynamic

Titration: DOS

EDITOR

2.3.12.1 DOS (Dispensing)

In this titration mode the titrator acquires not only the raw results mL (VEQ) or mmol (Q) but also the potential values ET1 and ET2 or ET3 before and after dispensing. The titrator recognizes four different dispensing modes.

Selection menu Dose 1

You can dispense a specified volume. You either enter the number of mL directly or you let the titrator calculate this if you know the nominal content of the sample to be titrated.

1. Select mL and enter the volume. A formula, such as "VDISP ∗ 1.2", can be entered instead of a number (VDISP is the volume dispensed in a preceding Dispense function).

2. Select % nominal content (see Section 8.6.3); you must enter the following values here:

• the metered amount in % of the nominal consumption

• the nominal content

• the conversion constant You can select this constant from the recommendation

menu.

• the maximum volume [mL]. It is intended as a safeguard: If, for instance, the wrong

constant has been selected excess titrant is not dispensed needlessly.

If you press the HELP key (selector bar is positioned on

Conversion constant)

the titrator

lists the constants with the corresponding units.

3. No: You do not need this dispensing mode.

Note: With these dispensing parameters the titrator waits for establishment of an equilibrium

in the solution before it acquires the initial potential ET1. It then dispenses and after reestablishment of equilibrium acquires ET2.

Selection menu Dose 2

You can dispense either to a specified potential or a specified slope of the titration curve.

1. When you select potential you obtain the following parameters:

• Potential: Enter the potential [mV, pH, …].

• Maximum volume [mL]: Enter the volume. It is intended as a safeguard: If, for instance,

the wrong parameters have been selected excess titrant is not dispensed needlessly.

2-34

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Titration: DOS

2. When you select the slope you obtain the following parameters:

• Slope: Enter the slope [mV, pH,…/mL].

• Maximum volume [mL]: Enter the volume (see point 1).

3. No: You do not need this dispensing mode. Notes: a. With these dispensing parameters the titrator dispenses dynamically with equilibrium-

controlled acquisition of the measured value (see representation under Section

2.3.12.2:

Titration mode EQP: Measure mode EQU

): It acquires the potential

values ET1 and ET3.

b. You can link Dose 1 with Dose 2.

E [mV]

ET3 ET3

ET2 ET1

V [mL]

a: mL or nominal content dispensing b: dispensing to a potential c: dispensing to the slope of the curve

02/93 METTLER DL77/DL70ES/DL67 2-35

Titration: EQP

EDITOR

2.3.12.2 EQP (Equivalence point titration)

The equivalence point is the point at which exactly the same number of equivalents of titrant and analyte have reacted. In most cases it is virtually identical to the inflection point of the titration curve. This inflection point is recognized (EPOT = equivalence point potential) and the equivalence point calculated (VEQ or Q = mL or mmol consumption up to the equivalence point). With this titration mode the titrator also determines the half neutralization value EHNV as a raw result.

Parameters of the mask: Predispensing 1

Predispensing 2 Titrant addition Measure mode

(Equivalence point recognition): Threshold

................................................. EQP range

(Termination criteria): Maximum volume [mL]

.................................. Termination at potential

.................................. Termination after n EQP´s

.................................. Termination at slope

.................................. Termn (ination) after nom.(inal) consumption

.................................. Combined termn (ination) criteria

(Evaluation criteria): Evaluation procedure

................................ Steepest jump only

................................ Buffer potential 1

................................ Buffer potential 2

................................ Stop for reevaluation

2-36

METTLER DL77/DL70ES/DL67

02/93

EDITOR

02/93 METTLER DL77/DL70ES/DL67 2-37

EDITOR

2-38

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Titration: EQP: Predispensing

A predispensing shortens the titration time. The titrator recognizes four predispensing modes.

Selection menu Predispensing 1

Under this selection menu you can predispense a certain volume. You either enter the number of mL directly or you let the titrator calculate this if you know the nominal content of the sample to be titrated.

1. Select mL and enter the volume. A formula, such as "VDISP ∗ 1.2", can be entered instead of a number (VDISP is the volume dispensed in a preceding Dispense function).

2. Select % nominal content (see Section 8.6.3); you must enter the following values:

• the metered amount in % of nominal consumption

• the nominal content

• the conversion constant. You can select this constant from the recommendation menu. If you press the HELP key (selector bar is positioned on

Conversion constant)

the titrator

lists the constants with the corresponding units.

3. No: You do not need this kind of predispensing.

Note: The titrator dispenses the titrant in three steps (4/7, 2/7, 1/7 of the specified volume),

which allows optimum calculation of the volume increment added when a dynamic titration follows. It acquires the potential values ET1 and ET2 (see titration mode

DOS,

Section 2.3.12.1).

Selection menu Predispensing 2

You can predispense to either a specified potential or a specified slope of the titration curve.

1. Enter the potential [mV, pH, ...].

2. Enter the slope [mV, pH, .../mL].

3. No: You do not need this kind of predispensing.

Notes: a. The titrant addition in this predispensing mode follows the selected parameters of

the main titration, however, the increments are greater. The titrator also registers the measured values quicker and acquires the potential values ET1 and ET3 (see titration mode

DOS

, Section 2.3.12.1).

b. You can link Predispensing 1 with Predispensing 2.

02/93 METTLER DL77/DL70ES/DL67 2-39

Titration: EQP: DYN

EDITOR

Selection menu Titrant addition

You can select the dynamic (DYN) or incremental (INC) addition mode. You can not decide the optimum addition mode for your titration until you know what type of titration curve you have.

DYN

The volume increment added by the titrator changes within the defined limits ∆V(min) and ∆V(max). This should lead to a constant potential difference ∆E per increment.

E [mV]

∆E ~ ∆E(set)

∆E

∆V

V [mL]

1. Enter ∆E(set) [mV]: e.g. 10.

2. Select the limits ∆V and enter ∆V(min) (smallest increment) and ∆V(max) (largest incre- ment) as absolute or relative values:

a. Absolute

– Enter ∆V(min) [mL]: e.g. 0.05 (see following page). – Enter ∆V(max) [mL]: e.g. 0.3.

Notes: a. The smallest increment, that the titrator can add, is 1/5'000 of the burette volume:

1 mL burette –> 0.0002 mL 5 mL burette –> 0.001 mL 10 mL burette –> 0.002 mL 20 mL burette –> 0.004 mL

b. If no predispensing takes place, the titrator adds the first two volume increments

with ∆V(min).

2-40

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Titration: EQP: INC

2 b. Relative

– Enter ∆V(min) [%dosVol]: refers to the volume already dispensed, in other words the

minimum set increment increases during the course of the titration.

– Enter ∆V(max) [%buVol]: refers to the burette volume and remains constant.

Note: If no predispensing takes place, the titrator calculates and dispenses first two volume

increments relative to 10% of the burette volume.

INC

The volume increment added by the titrator remains constant.

1. Enter ∆V [mL], e.g. 0.1.

E [mV]

∆E

∆V ∆V

∆V = constant

V [mL]

02/93 METTLER DL77/DL70ES/DL67 2-41

Titration: EQP: EQU

EDITOR

Selection menu Measure mode

You can select the equilibrium controlled (EQU) or time controlled (TFIX) measured value acquisition. This determines the waiting time between addition of the increments. Using EQU the waiting time is variable, using TFIX it is constant. You can not decide the optimum measure mode for your method until you know the reaction time of the components and the response time of the sensor used.

EQU

Before the titrator accepts a measured value, equilibrium must be established in the solution. The following parameters are responsible for the equilibrium

∆E potential change of the solution ∆t within a time

Time limits between the increments are the parameters t(min) minimum time t(max) maximum time

As soon as the potential change of the solution is smaller than the specified equilibrium (∆E/∆t), the titrator will acquire the measured value and add the next increment.

This can be established at the earliest at t(min) and should be established at the latest at t(max). At t(max) the measured value is acquired at all events even if the equilibrium condition has not yet been met.

Examples for equilibrium conditions

fast titrations slow titrations (acid-base titrations (precipitation titrations in aqueous media) in non-aqueous media)

1. Enter ∆E [mV]: 1 0.5

2. Enter ∆t [s]: 1 2

3. Enter t(min) [s]: 3 4

4. Enter t(max) [s]: 15 30

Notes: a. When measuring in EQU, increment addition is rapid in the flat segment of the

titration curve and slow in the steep segment.

b. The titrator acquires the time and the titrant volume together with the potential.

These measured values can be printed after the sample has been titrated (see Section 2.3.19:

2-42

Record

METTLER DL77/DL70ES/DL67

02/93

EDITOR

E [mV]

164

163

162

Titration: EQP: EQU

161

160

159

158

157

156

155

154

153

152

151

∆t = 2 s

t (min)

Increment addition

∆E = 1 mV

∆t = 2 s

t(min)

Increment addition

∆E = 1 mV

t [s]

1 5

0 1 t(min) 5

t(min)

a: The defined equilibrium condition has not been satisfied. t(min): The equilibrium condition has not been satisfied after 3 s. b: The equilibrium condition has been satisfied after 5.4 or 6.9 s for the first time.

02/93 METTLER DL77/DL70ES/DL67 2-43

Titration: EQP: TFIX

EDITOR

TFIX

After each increment addition the titrator waits for the time you have defined before it accepts the measured value.

1. Enter ∆t [s].

E [mV]

Measured value

Measured value Measured value

Measured value

Increment addition

∆t = 3 s ∆t

12 3

= 3 s ∆t = 3 s

t [s]

2-44

METTLER DL77/DL70ES/DL67

02/93

EDITOR

Titration: EQP: Threshold

Equivalence point recognition

The equivalence point recognition with a titration curve depends on the reaction type of the components and hence on the evaluation procedure (see below this section).

1. In the evaluation procedures Maximum and Minimum an equivalence point is recognized when the highest (lowest) potential value of the titration curve is greater (smaller) than two preceding and two subsequent values.

2. In the evaluation procedures Standard and Asymmetric an equivalence point is recognized when the maximum of the absolute values of the 1st derivative of the titration curve is greater than two preceding and two subsequent values.

3. In the evaluation procedure Segmented an equivalence point is recognized when the maximum of the absolute values of the 2nd derivative of the titration curve is greater than two preceding and two subsequent values.

Note: For the earliest possible recognition of an equivalence point, the titrator requires a

certain number of measurement points.

• The number depends on the evaluation procedure.

• Measurement points from a predispensing are not considered!

Evaluation procedure Earliest possible Measurement

EQP at points necessary

Minimum/Maximum 4th measurement point 6 Standard 4th measurement point 6 Asymmetric 4th measurement point 10 Segmented 5th measurement point 8

An example for the evaluation procedure Minimum: If the third measurement point lies in the vicinity of the lowest potential value, it will not be recognized as an equivalence point.

You must or can assist the recognition using two parameters.

Threshold

To prevent small disturbances in the curve being identified as an equivalence point, you must specify a threshold value: ([+/-mV, pH...], [mV, pH.../mL] or [mV, pH.../mL2]). This must be exceeded.

Note: a. The maximum value of the threshold should not exceed half the expected maximum

value of the first or second derivative at the equivalence point.

02/93 METTLER DL77/DL70ES/DL67 2-45

Titration: EQP: Threshold

EDITOR

Note: b. The maximum or minimum, the maximum of the absolute values of the 1st deri-

vative and the maximum of the absolute values of the 2nd derivative of a titration curve all depend on so many factors (solvent, concentration, sensor, type of reaction, etc.) that you can not define the "right" threshold value until you have performed the first titration. You can enter one of the following values for this:

Evaluation procedure mV pH/pM/pX %T

Minimum/Maximum 0 0 0 Standard/Asymmetric 10 0.2 1 Segmented 10 0.2 1

With the aid of the appropriate titration curve or table of measured values (there is no table for the 2nd derivative) you can read off the potential value, the values for ∆E/∆V or the values for ∆2E/∆V2 and then enter the threshold value.

1. Example of the threshold value of a titration curve for the evaluation procedure Minimum: The minimum of this titration curve is at -150 mV. You can enter, for instance, -30 as thresh-

old value. The sign for the mV value must also be entered.

E [mV]

+200

100

-30

-100

Threshold value

2-46

-200

Minimum

METTLER DL77/DL70ES/DL67

V [mL]

02/93

EDITOR

Titration: EQP: Threshold

2. Example of the threshold value of a titration curve for the evaluation procedures Standard and Asymmetric:

E [mV]

Titration curve

1st derivative

V [mL]

∆E/∆V [mV/mL]

Maximum (absolute)

Measured value

Threshold

V [mL]

02/93 METTLER DL77/DL70ES/DL67 2-47

Titration: EQP: Threshold

EDITOR

3. Example of the threshold value of a titration curve for the evaluation procedure Seg- mented:

Titration curve

1st derivative

E [mV]

V [mL]

∆E/∆V [mV/mL]

2-48

2nd derivative

∆

∆ E/∆V [mV/mL ]

222

E/∆V2 [mV/mL2]

Threshold value

METTLER DL77/DL70ES/DL67

V [mL]

Maximum (absolute)

Measured value

V [mL]

02/93

Mettler Toledo D77, DL70ES, DL67 Operating Instructions Manual

Specifications and Main Features

Frequently Asked Questions

User Manual