Metrohm 794 User Manual
CH-9101 Herisau/Switzerland
E-Mail info@metrohm.com
Internet www.metrohm.com
794 Basic Titrino
Program version 5.794.0010
Instructions for Use
8.794.1003 02.2002 / pkl
Table of contens
Table of contents
1 Introduction...........................................................................................................1
1.1 Instrument description........................................................................................... 1
1.2 Controls and parts................................................................................................. 2
2
Manual operation..................................................................................................6
2.1 Keypad ..................................................................................................................6
2.2 Principle of data input............................................................................................ 7
2.3 Text input ...............................................................................................................8
2.4 Tutorial ................................................................................................................... 9
2.4.1 Entering data, setting the dialog language....................................................9
2.4.2 Development of a method, titration of an acid.............................................11
2.4.3 Storage and loading of methods ................................................................. 16
2.4.4 pH calibration.............................................................................................. 17
2.4.5 Statistics, acid capacity of drinking water.................................................... 18
2.5 Configuration, key <CONFIG>...........................................................................22
2.6 Selection of the mode, key <MODE> ................................................................ 24
2.7 Parameters, key <PARAM> ............................................................................... 26
2.7.1 Parameters for DET and MET ...................................................................... 26
2.7.2 Parameters for SET ......................................................................................36
2.7.3 Parameters for MEAS................................................................................... 45
2.7.4 Parameters for CAL......................................................................................47
2.7.5 Parameters for TIP .......................................................................................50
2.8 Result calculations............................................................................................... 52
2.9 Statistics calculation ............................................................................................55
2.10 Common variables ..............................................................................................57
2.11 Data output.......................................................................................................... 58
2.12 TIP, Titration procedure ....................................................................................... 62
2.13 Method memory, keys <USER METH> ............................................................. 66
2.14 Calibration data, key <CAL.DATA> ...................................................................68
2.15 Current sample data, key <SMPL DATA> .........................................................69
2.16 Silo memory for sample data ..............................................................................70
2.17 Storing determination results and silo calculations............................................. 73
2.17.1 Storing determination results .......................................................................73
2.17.2 Silo calculations ........................................................................................... 74
3
Operation via RS232 Interface...........................................................................77
3.1 General rules .......................................................................................................77
3.1.1 Call up of objects .........................................................................................78
3.1.2 Triggers ........................................................................................................79
3.1.3 Status messages .........................................................................................80
3.1.4 Error messages............................................................................................82
3.2 Remote control commands................................................................................. 85
3.2.1 Overview.......................................................................................................85
3.2.2 Description of the remote control commands ........................................... 102
3.3 Properties of the RS 232 Interface.....................................................................125
3.3.1 Handshake................................................................................................. 125
3.3.2 Pin Assignment .......................................................................................... 129
3.3.3 What can you do if the data transfer does not work? ................................ 131
794 Basic Titrino
Table of contents
4
Error messages, Troubleshooting...................................................................133
4.1 Error and special messages ............................................................................. 133
4.2 Diagnosis .......................................................................................................... 137
4.2.1 General ...................................................................................................... 137
4.2.2 Procedure .................................................................................................. 137
4.2.3 Equipment required: .................................................................................. 138
4.2.4 Diagnosis steps ......................................................................................... 138
4.3 Initialise and test RAM....................................................................................... 147
4.4 Releasing a locked spindle ............................................................................... 148
5
Preparations .....................................................................................................149
5.1 Setting up and connecting the instruments ...................................................... 149
5.1.1 Titrino with Stirrer or Titration Stand........................................................... 149
5.1.2 Connection of a printer .............................................................................. 150
5.1.3 Connection of a balance............................................................................ 151
5.1.4 Connection of a Sample Changer ............................................................. 152
5.1.5 Connection of a recorder........................................................................... 153
5.1.6 Connection of a computer......................................................................... 154
5.2 Connection of electrodes, preparing titration vessel ........................................ 155
6
Appendix ...........................................................................................................158
6.1 Technical specifications.................................................................................... 158
6.2 Pin assignment of the "Remote" socket ............................................................ 161
6.2.1 Lines of the "Remote" socket during the titration....................................... 163
6.2.2 Possible configurations of the activate pulse in SET and CAL.................. 164
6.3 User methods.................................................................................................... 165
6.3.1 General ...................................................................................................... 165
6.3.2 "Titer_pH" ................................................................................................... 166
6.3.3 "Blank"........................................................................................................ 167
6.3.4 "Chloride" ................................................................................................... 168
6.3.5 "TAN-TBN".................................................................................................. 169
6.3.6 "Diazo"........................................................................................................ 170
6.3.7 "Br-Index" ................................................................................................... 171
6.3.8 "Sapon.No"................................................................................................. 172
6.3.9 "Ca-Mg"...................................................................................................... 173
6.3.10 "EDTA-NTA"................................................................................................ 174
6.3.11 "Metals" ...................................................................................................... 175
6.3.12 "Perox.No" .................................................................................................. 176
6.3.13 "FormolNo""................................................................................................ 177
6.3.14 "P2O5Fert""................................................................................................. 180
6.4 Validation / GLP................................................................................................. 183
6.5 Warranty and conformity ................................................................................... 184
6.5.1 Warranty..................................................................................................... 184
6.5.2 EU Declaration of conformity..................................................................... 185
6.5.3 Certificate of Conformity and System Validation ....................................... 186
6.6 Scope of delivery and ordering designations ................................................... 187
Index.........................................................................................................................190
794 Basic Titrino
1.1 Instrument description
1 Introduction
1.1 Instrument description
The 794 Basic Titrino is an all-purpose titrator. Titration modes of the 794 Basic Titrino are
constant or – depending on the titration curve – variable dosing of the titration reagent
and Endpoint-Titration.
All operating modes of the Titrino can be combined to perform extensive analytical sequences. Ready-to-start methods for the most common applications are stored in the
internal method memory. The operator is free to modify and overwrite this methods or to
create and store his own titration sequences.
Data exchange with a PC is possible with the Metrodata VESUV Software and with Metrodata TiNet Software complete remote control, data acquisition and evaluation via PC is
enabled.
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1.2 Controls and parts
1.2 Controls and parts
Front view of instrument:
794 Basic Titrino
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1.2 Controls and parts
1 Exchange Unit
2 Display
3 Setting of display contrast
4 Controls the dosing rate during manual dosing with <DOS> and subse-
quent filling
5 Control keys and indicator lamps on the Titrino
Key <DOS> Dosing key. Dispensing is performed as long as <DOS> is being
pressed. Used e.g. to prepare the Exchange Unit. The dispensing
rate can be set with potentiometer (4).
Key <STOP/FILL> - Stops procedures, e.g. titrations, conditioning.
- Filling after manual dosing with <DOS>.
Key <START> Starts procedures, e.g. titrations, conditioning.
Identical with key <START> of the separate keypad.
Indicator lamps:
"Statistics" Lamp is on when the "statistics" function (calculation of mean and
standard deviation) is on.
"Silo" Lamp is on when silo memory (for sample data) is on.
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1.2 Controls and parts
Rear view of instrument:
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1.2 Controls and parts
6 RS232 interface
for the connection of printer, balance or a computer
7 Remote lines
(input/output)
for the connection of the Remote Box, Sample Changers, robots etc.
8 Connection of electrodes and temperature sensor
• 2 high-impedance measuring inputs for pH and U measurements (Ind I/ Ind II).
They can either be used separately or for differential potentiometry, see page
155.
Important: If you work with both measuring inputs in the same vessel, the same
reference electrode must be used.
• 1 measuring input for polarized electrodes (Pol).
• 1 measuring input for PT100 or Pt1000 temperature sensor.
9 Connection for separate keypad
10 Analog output for the connection of a recorder
11 Connection for power cable
With power supplies where the voltage is subject to severe HF disturbances, the Titrino should be operated via an additional power filter, e.g. Metrohm 615 model.
12 Mains switch
13 Earthing socket
14 Connection for stirrer
728 Magnetic Stirrer, 802 Rod Stirrer, 703 or 727 Ti Stand
Supply voltage: 9 VDC (I ≤ 200 mA)
15 Display of the set mains voltage
Before switching on for the first time, check that the set mains voltage matches the
voltage of your power supply. If this is not the case, disconnect mains cable and
change voltage.
16 Rating plate
with fabrication, series and instrument number
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2.1. Keypad
2 Manual operation
2.1 Keypad
CONFIG Configuration.
PARAM Parameters.
SMPL DATA Sample data.
STATISTICS ON/OFF switching of statistics calcu-
lations of consecutive determination,
see page 55.
MEAS/HOLD ON/OFF switching of measurements
between titrations and hold during
titrations.
SILO ON/OFF switching of silo memory for
sample data, see page 69.
CAL.DATA Calibration data, see page 68.
C-FMLA Calculation values, see page 54.
DEF Formulas, data output, sequence for
TIP, see page 52ff.
USER METH Management of internal method
memory, see page 66.
PRINT Printing of reports, see page 60.
REPORTS Result output.
MODE Mode selection, see page 24.
<,> Keys for text input.
SELECT Selection of special values (dialog
marked with ":")
CLEAR Clears values, set special values.
ENTER Stores values.
STOP Stops methods.
QUIT Quits inquiries, waiting times, printing.
START Starts methods.
The third functions (inscriptions in the triangle) on the keys of the keypad are used for
formula entry, see page 52.
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2.2 Principle of data input
2.2 Principle of data input
• If you press a key you will find the corresponding
menu in the display.
Example key <CONFIG>:
configuration
>peripheral units
>peripheral units
send to: IBM
configuration
>auxiliaries
DET pH ********
In the first line you see where you are: You pressed
key <CONFIG> and you are now in the menu "configuration".
• In our example you are in the menu "configuration"
on the title ">peripheral units". By pressing
<CONFIG> you can move to the other titles of this
menu.
• If a dialog text is marked with ">", it contains a
group of inquiries. You branch into this group by
pressing <ENTER>.
Example inquiries of "peripheral units":
The first line indicates again where you are.
If a dialog text of an inquiry is marked with ":", you
can select a value with the key <SELECT>.
• A value is stored with <ENTER> and the cursor
moves to the next inquiry.
• Repeated pressing of <ENTER> moves you
through the inquiries of the group ">peripheral
units“, after the last inquiry of this group you leave
this group and return to the level above.
The next group of the menu "configuration“ appears:
">auxiliaries“
• With key <QUIT> you leave an inquiry or a group of
inquiries, it always
• In this example you leave the menu "configuration"
by pressing <QUIT> and return to the display of titration mode and the chosen method.
moves you one level up.
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2.3. Text input
2.3 Text input
<USER METH>
user methods
>recall method
<USER METH>
<ENTER>
>store method
method name:
<CLEAR>
<<>
>store method
method name: ABCDEFG
<QUIT>
<ENTER>
>store method
method name: text
Example storing a method:
• Press key <USER METH>, the group ">recall
method" appears.
• Choose ">store method" by pressing <USER
METH> and press <ENTER>.
The name of the method which is currently in the
working memory is displayed.
• Delete this name with <CLEAR>.
• Open the "text writing mode" with key <<>.
• Select the character marked by the blinking cursor
with the Keys <<> and <>>, confirm it with
<ENTER>. Select the next character...
When you confirmed the last character, i.e. your
name is complete, you quit the text writing mode
with <QUIT>.
Confirm now the name with <ENTER>.
If your text fills the whole text field, just press
<ENTER> to store the text.
• During text input you can correct typing errors with
<CLEAR>:
<CLEAR> deletes the characters one by one.
• If you wish to modify an existing name (e.g. if you
have names like Text 1, Text 2, Text 3), do not delete
the existing name before you start the text input
mode. Proceed then as follows:
1. Press <USER METH>, place the cursor to
">store method" and press <ENTER>.
2. Open the text writing mode directly: Press key
<<>.
3. <CLEAR> now deletes the characters one by
one or you can add additional characters.
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2.4 Tutorial
2.4 Tutorial
This short operating course teaches you to work quick and efficient with the 794 Basic
Titrino, by means of the most important applications.
Set up your Titrino and connect the peripheral devices needed, see chapter 5.
2.4.1 Entering data, setting the dialog language
We can thus make a start and first take a look at the fundamentals of the entry of data.
We change the dialog language.
DET pH ********
<CONFIG>
configuration
>peripheral units
<CONFIG>
configuration
>auxilliaries
<ENTER>
>auxilliaries
dialog: english
<SELECT>
>auxilliaries
dialog: español
<ENTER>
>ajustes varios
fecha 2002-01-02
• Switch on the Titrino. It is now in the standby state, it
shows you the active mode and method name.
• Press the key <CONFIG>, the display shows:
This is the title of the group "peripheral units". This
group contains various inquiries about peripheral
units.
• Press again <CONFIG>. You see the title of a new
group of inquiries.
This "auxiliaries" group contains the inquiry for the
dialog language.
• Pressing the <ENTER> key takes you to the inquir-
ies of the group "auxiliaries". Note the ">" sign. All titles of inquiry groups are prefixed by this sign.
This is the first inquiry of the "auxiliaries" group: the
selection of the dialog language.
• You select the various dialog languages with the
<SELECT> key. Press <SELECT> repeatedly until
"español" appears in the display.
Note the sign ":". It appears if the values can be selected with the key <SELECT>.
• Accept the new "value" with <ENTER>.
The next inquiry "fecha" (date) of the group "ajustes
varios" (auxiliaries) is shown.
You can open this inquiry by pressing <ENTER>
too and go through all the inquiries of this group this
way.
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2.4. Tutorial
<QUIT>
configuration
>ajustes varios
<QUIT>
DET pH ********
Because this inquiry follows no colon ":" the value
can't be selected by <SELECT>, the date "fecha"
has to be entered with the numeric keys.
• Exit the inquiries with <QUIT>. You are one level
higher in the "configuration" menu showing the title
"ajustes varios" (auxiliaries).
• Press <QUIT> once again to exit the "configuration"
menu and return to the standby state.
All the dialog texts will now be displayed in Spanish.
If you prefer English as the displayed dialog language, proceed as before and select "English".
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2.4 Tutorial
2.4.2 Development of a method, titration of an acid
Selection of the mode
<MODE>
mode
mode DET
<ENTER>
DET pH ********
DET: pH
4 × <SELECT>
DET pH ********
For the titration put a Exchange Unit with c(NaOH) = 0.1 mol/L on the Titrino and rinse
the tubing and the buret Tipp with <DOS>. Fill the buret again with <STOP/FILL>.
Plug a combined pH glass electrode into measuring input 1 (Ind I).
Pipette 2 mL c(HCl) = 0.1 mol/L into your titration vessel, dilute with ca. 20 mL dist. water.
Put a magnetic stirrer in the titration vessel and place buret tip and electrode in the probe,
see page 157 for their arrangement.
Start the stirrer and press <START>
During the titration the first line of the display shows the current measured value and the
volume already dispensed:
• Press <MODE> repeatedly until "DET" appears in
the display. For a description of the DET mode see
page 25.
• Confirm "DET" with <ENTER>
• Now select the measured quantity: Press
<SELECT> repeatedly until "pH" appears again in
the display.
Confirm the measured quantity "pH" with
<ENTER>.
You are now ready to titrate.
pH 3.02 0.351 ml
As soon as the instrument has found an equivalence point, this is shown on the second
line:
pH 7.64 2.083 ml
EP1
Let the titration continue for a short while, e.g. until ca. pH 11.50. Now stop it with
<STOP>.
DET pH ********
EP1 2.083 ml pH 7.64
The first line now shows the mode "DET pH" and the name of the chosen method (here
"********" because this method has not been saved under a own name until now). Of
interest is the second line, which shows the equivalence point found.
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2.4. Tutorial
If more than one equivalence point has been found, the others can be viewed with
<ENTER>.
Calculation of the result: formula entry
<DEF>
def
>formula
<ENTER>
RS?
<1>
RS1=
RS1=EP1*C01*C02/C00
<ENTER>
>formula
RS1 text RS1
>formula
RS1 decimal places 2
>formula
RS1 unit %
<SELECT>
<ENTER>
RS?
2 x <QUIT>
With this equivalence point a result can be calculated.
• Press the <DEF> key.
• Press <ENTER> to move on to the formula entry.
The display now shows "RS?".
• Press "1", i.e. the first formula.
You now can enter a formula. Note here the top inscription on the keys of the keypad and the numbers. The
following symbols can be used:
EP# EP's with 1-digit number, e.g. EP1.
RS# Previously calculated results, e.g. RS1 in the sec-
ond formula.
C## Calculation constant with 2-digit number, e.g. C01.
C00 is reserved for the sample size. For the meaning of the calculation constants see page 53.
Calculate the content of your hydrochloric acid in g/L:
RS1=EP1*C01*C02/C00
End point*conc.(titrant)*molecular weight/sample size
To correct a formula, delete it with <CLEAR>.
• Confirm the formula with <ENTER>.
• You may enter a text for the result output, see page
8.
• Enter the desired number of decimal places for the
result.
• Select the desired unit g/L with <SELECT>, or type
a text as unit, see page 8.
The Titrino prompts for the calculation of the next result.
Quit the formula entry by pressing <QUIT> twice.
In order to be able to calculate the result, enter the calculation constants used in the formula.
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2.4 Tutorial
Entry of the calculation constants
<C-FMLA>
C-fmla
>C01 0.0
• Press <C-FMLA>.
The constants which have been used in the formula
are requested: input with digit keys, confirm with
<ENTER>.
C01: Concentration of your titrant= 0.1 mol/L. Enter
0.1.
C02: Molar mass of HCl = 36.47 g/mol
Entry of the sample size
4 x <SMPL DATA>
smpl data
smpl size 1.0 g
<2>
<ENTER>
smpl data
smpl unit: g
<SELECT>
<ENTER>
• Press <SMPL DATA> repeatedly until "sample size"
appears in the display.
• Enter 2.
• Use <SELECT> to select the unit "mL" and confirm
the new value with <ENTER>.
The result is now calculated and can be displayed in place of the equivalence point. If
your method already includes a formula at the end of the titration, the calculated result is
displayed directly after the titration. As we have entered the formula later, we now have to
select the result display:
Display of the result
<SELECT>
DET pH ********
>display results
<ENTER>
DET pH ********
RS1 3.80 g/l
• Press <SELECT> repeatedly until ">display results"
appears in the display.
• Press <ENTER> to move to the result display.
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2.4. Tutorial
If you have a printer connected, you probably wish to have the curve and a result report
printed out automatically at the end of a titration.
To install a printer, see page 150.
Print reports
4 x <DEF>
def
>report
<ENTER>
report:
6 x <SELECT>
<;>
9 x <SELECT>
report:curve;full
<ENTER>
<QUIT>
• Press <DEF> repeatedly until the display shows:
• Press <ENTER> to move to the definition of reports.
• With <SELECT> you select the individual repot
blocks. Use a ";" as delimiter between the report
blocks to print more than one block. If you wish to
print out a curve and a full result report, enter
"curve;full".
• Confirm the entry with <ENTER> and quit the inquir-
ies with <QUIT>.
Now print your reports by pressing <PRINT><REPORTS><ENTER>. Your printout will
look like the following:
'cu
794 Titrino 01102 794.0010
date 2002-01-03 time 17:34 1
start V 0.000 ml DET pH ********
1.0 ml/div dpH=2.0/div
−−−−−−−−−−−−−−−−
'fr
794 Titrino 01102 794.0010
date 2002-01-03 time 17:34 1
pH(init) 2.88 DET pH ********
smpl size 2 ml
EP1 2.083 ml 7.64
RS1 3.80 g/l
manual stop
−−−−−−−−−−−−−−−−
Identification of the report type (cu=curve)
Start volume, mode and method name
Scaling of curve axis
Identification of the report type (fr=full report)
Device type with identification and program version
Initial pH, mode and method name
Volume and pH value of EP1
Calculated result
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2.4 Tutorial
So that you do not have to stop your titration manually each time, let us add a stop criterion for the titration.
Stop criterion
2 x <PARAM>
parameters
>stop conditions
<ENTER>
>stop conditions
stop V: abs.
<ENTER>
>stop conditions
stop V: 99.99 ml
<ENTER>
>stop conditions
stop pH OFF
<ENTER>
2 x <QUIT>
• Press <PARAM> twice to display the title ">stop
conditions".
• Open this group of inquiries with <ENTER>.
Absolute stop volume. This can be used as a safety
measure to prevent overflow of the titration vessel.
The magnitude of the absolute stop volume. Set a value
that appears suitable for your titration vessel.
Set the pH value, e.g. pH=11.5 as the expected stop
criterion.
If several stop criteria have been set, the one that is
reached first applies.
Confirm your entries with <ENTER> and quit the inquiry
with <QUIT>.
The development of your method is now complete. Before we store it in the method memory, you should check it again. Prepare a fresh sample and restart the titration with
<START>.
If everything appears to be all right, you can now store the method in the method memory.
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2.4. Tutorial
Y
2.4.3 Storage and loading of methods
Now store the method you have just developed in the method memory.
Storage of a method
2 × <USER METH>
user methods
>store method
<ENTER>
>store method
method name: ********
<ENTER>
DET pH Acid
If you have a printer connected, you can print out the contents of your method memory.
Key sequence: <PRINT><USER METH><ENTER>
Stored methods can be loaded at any time.
Loading a method from the method memory
<USER METH>
user methods
>recall method
<ENTER>
>recall method
method name: ********
<SELECT>
or
direct entry
<ENTER>
DET pH Acid
• Press <USER METH> repeatedly until the title
">store method" appears in the display.
• Open the inquiry with <ENTER>.
• Enter an identifier, e.g. 1 or Acid.
For text input see page 8.
The method now runs under the name "Acid". It is ready
to titrate.
• Press <USER METH>. The display shows the title
">recall method".
• Open the inquiry <ENTER>
•
ou can select the desired method with <SELECT>
(it shows all methods of the method memory one after the other) or by directly enter the method name.
• Load the method with <ENTER>
The method is ready to titrate.
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2.4 Tutorial
2.4.4 pH calibration
pH calibrations are not a requirement for pH titrations, when the equivalence point is determined from a curve. For end-point titrations, however, where titration is performed to a
fixed, specified pH value, a calibration should be performed.
Selection of the calibration mode, CAL
<MODE>
mode
mode CAL
<ENTER>
CAL ********
pH(as) 7.00 slope 1.000
Calibration procedure
<START>
CAL
cal.temp. 25.0°C
<ENTER>
25.0°C
buffer 1 pH 7.00
<ENTER>
25.0°C
buffer 2 pH 4.00
<ENTER>
oder
<STOP>
CAL ********
pH(as) 6.89 slope 0.985
The calibration data can be viewed at any time under the <CAL.DATA> key. Our calibration data are stored under ">input 1".
The calibration report can be printed out at any time with the key sequence:
<PRINT><CAL.DATA><ENTER>
• Press <MODE> repeatedly until "CAL" appears in
the display and confirm the mode with <ENTER>.
The instrument is ready for a 2-point calibration. The
second display line shows the current calibration data
for measuring input 1.
• Immerse your electrode in the first buffer and start
the calibration procedure.
Inquiry of calibration temperature.
• Enter the current temperature. If you have a tem-
perature sensor connected, this inquiry is skipped.
pH value of the first buffer.
• Enter the pH value of the buffer at your calibration
temperature.
The voltage of the first buffer is measured. When the
measured value has met the set drift criterion, the
measurement is stopped and the pH value of the second buffer is requested.
• Now enter the pH value of the second buffer. If you
require a 1-point calibration, you can also terminate
the calibration with <STOP>.
At the end of the calibration, the calibration data obtained are displayed: asymmetry pH and slope.
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2.4. Tutorial
2.4.5 Statistics, acid capacity of drinking water
Let us now determine the acid capacity of drinking water. For this, the SET (set endpoint
titration) mode is used to titrate to pH = 4.3.
First select the mode SET pH (keys <MODE> and <SELECT>).
Now set the end point.
Entry of the end point and the control parameters
<PARAM>
parameters
>SET1
<ENTER>
>SET1
EP at pH OFF
>SET1
EP at pH 4.3
<ENTER>
>SET1
dynamics OFF
>SET1
dynamics 3
<ENTER>
>SET1
max.rate 10.0 ml/min
<ENTER>
>SET1
min.rate 25.0µl/min
2 × <QUIT>
Mount an Exchange Unit with c(HCl) = 0.1 mol/L as titrant. Add 25 mL drinking water as
sample and start the titration with <START>. During the titration the first line of the display shows the measured value and dispensed volume. The "c" in pHc shows that the
electrode assembly has been calibrated. The second line shows a "control bar", which
indicates the control deviation of the current measured value from the set end point.
• Press <PARAM>. The display shows:
Control parameters for EP1
• Set the end point to pH = 4.3.
• Dynamics means the control range in which the
adding of the titrant is controlled in dependence on
the measured value (OFF: largest control range, i.e.
slow titration).
With buffered systems such as drinking water, this
value can be set lower, e.g. to 3. I.e. 3 pH units before the set EP controlled dosing starts.
Maximum possible titration rate inside the control
range.
Minimum titration rate inside the control range.
• Quit the inquiry with <QUIT>.
pHc 6.34 0.426 ml
#======
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2.4 Tutorial
If the titration runs too slow or too fast, you can change the control parameters during the
titration. If you wish to titrate faster, change the following parameters:
• dynamics: lower value, the control range becomes smaller (Attention: possibility of
titrating over the set EP)
• max.rate: bigger value
• min.rate: bigger value
You will find further details of the control parameters on page 42.
After the titration, end point volume and pH value at the end point are displayed.
For the evaluation enter:
the formula to calculate the m value
(key <DEF>) RS1=EP1*C01*C02
with an accuracy of RS1 decimal places 2
the unit RS1 unit: mmol/L
and the calculation constants C01 1 (concentration of titrant ×10)
(key <C-FMLA>) C02 4 (factor for the sample size 100 mL/25 mL)
If you have a printer connected, select the automatic titration report (key <DEF>): "report:full". You can print out the results of the previous titration with keys
<PRINT><REPORTS><ENTER>.
If the previous titration has run to your satisfaction, you can start thinking about performing statistics calculations. Have you already added a new sample to the titration vessel? If
you are no longer certain, you can find out immediately with <MEAS/HOLD>.
Rapid measurement between titrations
Press <MEAS/HOLD>. The pH value of your sample is displayed. You can stop the
measurement with a second <MEAS/HOLD>.
Statistics calculations
Now switch on the statistics calculations. Press <STATISTICS>. The "Statistics" LED is
on. Duplicate determinations are now performed.
• Perform 2 titrations.
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2.4. Tutorial
After the second titration you receive a printout with statistics calculations:
'fr
794 Titrino 01102 794.0010
date 2002-01-03 time 17:34 3
pHc(init) 6.29 SET pH ********
EP1 0.0628 ml 4.26
m value 5.02 mmol/l
mean(2) +/s s/%
m value 5.04 0.028 mmol/l 0.56
==============
If you have no printer connected, you can view the mean value and standard deviation:
• Press <SELECT> until "display mean" appears in the display.
• With <ENTER> you obtain the mean value.
• A second <ENTER> displays the number of single values which have been used for
the mean calculation.
• If you press <SELECT> again, the display "display std.deviation" appears. Once
again, you can view this value, by pressing <ENTER>.
Perhaps you have noticed that the two values differ too greatly? In any case, we shall perform a third determination with the same sample. The result of this determination will be
another value which is incorporated in the statistics calculations.
Addition of more determinations for the statistics calculations
5 × <PARAM>
parameters
>statistics
<ENTER>
>statistics
status: ON
<ENTER>
>statistics
mean: n= 2
<3>
<ENTER>
2 × <QUIT>
• Press <PARAM> until the display shows:
• Statistics calculations can be switched on either with
the <STATISTICS> key or in the inquiry "status:".
We shall leave them switched on and proceed to the
next inquiry.
Mean value of 2 single determinations.
• Enter "3" to include an additional determination.
• Quit the inquiry.
Perform another titration.
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2.4 Tutorial
You can now decide which of the results is an "outlier". You can delete it from the statistics
calculation.
Deleting a result from the statistics calculation
5 × <PARAM>
parameters
>statistics
3 × <ENTER>
>statistics
res.tab: original
2 × <SELECT>
>statistics
res.tab: delete n
<ENTER>
>statistics
delete n= 1
<2>
<ENTER>
2 × <QUIT>
• Press <PARAM> until the display shows:
• Select with <ENTER> the inquiry of the result table
"res.tab:"
• To delete a single result with index n from the result
table, press <SELECT> so that "delete n" appears.
• Enter index n of the result you wish to delete; in our
example the second:
• Quit the inquiry by pressing <QUIT>.
Mean value and standard deviation are recalculated
and can be viewed in the display.
With <PRINT><REPORTS><ENTER> you can print
a fresh report.
With <PRINT> <STATISTICS><ENTER> you can
print a statistics overview, in this report the deleted
result is marked with a "∗" in the report.
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2.5. Configuration, key <CONFIG>
2.5 Configuration, key <CONFIG>
CONFIG
configuration
>peripheral units
>peripheral units
send to: IBM
balance: Sartorius
record: U
Key <CONFIG> serves to enter device specific data.
The set values apply to all modes.
peripheral units:
Selection of printer, balance and the curve at the analog output.
auxiliaries:
e.g. setting of dialog language, date, time, etc.
RS232 settings:
RS parameters for the COM interface.
common variables:
Values of common variables.
The display texts of the Titrino are shown to the left.
The values are the default values.
Settings for peripheral units
Selection of printer (Epson, Seiko, Citizen, HP, IBM) at
the Titrino Rs232 interface.
"Epson", for Epson
"Seiko", e.g. for DPU-414
"Citizen", e.g. for iDP 562 RS, Custom DP40-S4N
"HP" e.g. for Desk Jet types. Place curves always at the
beginning of a page as you cannot have them over 2
pages.
"IBM" for all printers with IBM character set Table 437
and IBM graphics, as well as for the data transmission
to a computer with Metrodata software TiNET or
VESUV.
Selection of balance (Sartorius, Mettler, Mettler AT,
AND, Precisa)
Sartorius: Models MP8, MC1
Mettler: Models AM, PM, AX, MX, UMX and
balances with 011, 012, or 016 interface
Mettler AT: Model AT
AND: Models ER-60, 120, 180, 182, FR-200, 300
and FX-200, 300, 320
Precisa: Models with RS232C interface
Selection of the curve for the output at the analog
output (U, dU/dt, V, dV/dt, U(rel), T
U:. Voltage
dU/dt: Measured value drift
V: Volume
dV/dt Volume drift
U(rel): Control deviation with SET
T: Temperature with MEAS T
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2.5 Configuration, key <CONFIG>
>auxiliaries
dialog: english
date 2001-01-03
time 08:13
run number 0
auto start OFF
start delay 0 s
dev.label.
program 794.0010
>RS232 settings
baud rate: 9600
data bit: 8
stop bit: 1
parity: none
handshake: HWs
RS control: ON
General settings
Selection of dialog language (english, deutsch,
francais, español, italiano, portugese, svenska)
Current date (YYYY-MM-DD)
Format: Year-month-day, entry with leading zeros.
Current time (HH-MM)
Format: Hours-minutes, entry with leading zeros.
Current run number for result output (0...9999)
The sample number is set to 0 when the instrument is
switched on and incremented on every determination.
Automatic starts of titrations. (1...9999, OFF)
Number of automatic starts ("number of samples").
Used for instrument interconnections in which the
external instrument does not initiate a start. Not
advisable in connections with Sample Changers.
Start delay (0...999999 s)
Delay time after start of methods. Abort start delay time
with <QUIT>.
Individual identification of devices (up to 8 ASCII
characters)
Will be printed in the result report, see page 59.
Display of program version
Settings of RS232 interface
see also page 125ff.
Baud rate (300, 600, 1200, 2400, 4800, 9600)
Data bit (7, 8)
Stop bit (1, 2)
Parity (even, odd, none)
Handshake (HWs, HWf, SWline, SWchar, none)
see page 125ff.
Control via RS232 interface (ON, OFF)
"OFF" means that the receipt of commands via the
RS232 interface is blocked. Data output
is possible.
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2.6. Selection of the mode, key <MODE>
>common variables
C30 0.0
etc.
Values of the common variables
Common variables C30...C39 (0..
The values of all common variables are displayed. For
creating of common variables see page 57.
2.6 Selection of the mode, key <MODE>
MODE
>
;
–
Press key <MODE> until the desired mode is
displayed and confirm with <ENTER>.
Select the measured quantity pH, U, Ipol, Upol, (T) with
<SELECT> and confirm it also with <ENTER>.
The following modes can be selected:
• DET: Dynamic Equivalence-point Titration
• MET: Monotonic Equivalence-point Titration
• SET: Set Endpoint Titration.
• CAL: pH Calibration.
• MEAS: Measuring.
• TIP: Titration Procedure. Linking of various
commands and methods to a titration procedure.
These standard modes are equipped with a set of
standard parameters. They only need few settings in
order to be ready to work.
TIP is an empty "shell". The TIP sequence has to be
defined with <DEF>, see page 62.
±
999 999)
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2.6 Selection of the mode, key <MODE>
Overview of the titration modes
DET
Dynamic Equivalence
point Titration
Titration
Evaluation
Applications
Reagent feeding:
Variable volume increments,
depending on the slope of
the curve.
U/mV
Acquisition of measured
values:
Drift controlled ("equilibrium
titration")
and/or
after a fixed equilibration
time.
The evaluation of EP' s is
based on the zero crossing
of the second derivative with
a Metrohm correction for the
distortion of the curve from
superimposed jumps. Can
be combined with selectable
recognition criteria.
Recognition criteria:
as for MET
Suitable titration mode for
most problems. Specially
recommended if jumps lie
very close together and for
very flat jumps.
Note: The reagent feeding
algorithm is based on measured data. The curve should
therefore not deviate
markedly from S-shape.
V/mL
MET
Monotonic Equivalence
point Titration
Reagent feeding:
Constant volume increments, independent of the
slope of the curve.
U/mV
Acquisition of measured
values:
Drift controlled ("equilibrium
titration")
and/or
after a fixed equilibration
time.
The evaluation of EP's is
based on the Fortuin interpolation.
Recognition criteria:
all EP's
only the last EP
only the greatest EP
EP windows
For
• slow titration reactions
(diazotations, coupling
reactions)
• sluggish electrode
response.
V/mL
SET, KFT
Endpoint Titration
Titration to preset end-point.
U/mV
Control
range
Acquisition of measured
values:
Continuously
Volume that has been dispensed up to the endpoint
(EPX in mL).
• For rapid, quantitative
determinations in analytical chemistry. Requirement: EP of the titration reaction is
known and does not
change during a determination series.
• If an excess of titrant
must be avoided.
EP
V/mL
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2.7. Parameters, key <PARAM>
2.7 Parameters, key <PARAM>
The key <PARAM> is used for the entry of values that
PARAM
determine the modes. Values marked with "cond." are
accessible during the conditioning in the SET mode.
"**titr." means that these values can be changed during the titration. They influence the ongoing determination. Other values can only be changed in the inactive
state.
The display texts of the Titrino are shown to the left.
The values are the default values.
2.7.1 Parameters for DET and MET
parameters
>titration parameters
>titration parameters
meas.pt.density 4
DET
min.incr. 10.0 µl
DET
V step 0.10 ml
MET
titration parameters
determine the course of the titration and measured
value acquisition.
stop conditions:
Parameters for the automatic termination of the titration.
statistics:
Calculation of mean values and standard deviation,
see also page 55.
evaluation:
Parameters for the evaluation of EP's, fix EP's, and
pK/HNP.
preselections:
ON/OFF of various auxiliary functions such as automatic requests after the start and activate pulse.
General titration parameters
Measuring point density (0...9)
0 means highest density, 9 lowest. Selection of the
meas.pt.density, see page 32.
Minimum increment (0...999.9 µL)
The increment is dispensed at the beginning of the
titration and in the region of the equivalence point.
Size of volume increment (0...9.999 mL)
Dosing step. Small volume increments are needed to
determine blank values or to assure accuracy with
highly unsymmetrical curves. Selection of size of the
increment, see page 33.
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