Metrohm 799GPT User Manual
CH-9101 Herisau/Switzerland
E-Mail info@metrohm.com
Internet www.metrohm.com
799 GPT Titrino
Program version 5.799.0010
Instructions for Use
8.799.1003 12.2001 / pkl
Table of contents
Table of contents
1 Introduction ..............................................................................................................1
1.1 Instrument description ................................................................................................1
1.2 Controls and parts ...................................................................................................... 2
2 Manual operation......................................................................................................4
2.1 Keypad........................................................................................................................ 4
2.2 Principle of data input .................................................................................................5
2.3 Text input ....................................................................................................................6
2.4 Configuration, key <CONFIG>..................................................................................7
2.5 Selection of the mode, key <MODE> .....................................................................14
2.6 Parameters, key <PARAM>.....................................................................................15
2.6.1 Parameters for DET and MET ............................................................................15
2.6.2 Parameters for SET ............................................................................................25
2.6.3 Parameters for KFT ............................................................................................34
2.6 Parameters, key <PARAM>.....................................................................................42
2.6.4 Parameters for STAT ..........................................................................................43
2.6.5 Parameters for DOS........................................................................................... 55
2.6.6 Parameters for DOC........................................................................................... 62
2.6.7 Parameters for MEAS.........................................................................................69
2.6.8 Parameters for CAL............................................................................................71
2.6.9 Parameters for TIP .............................................................................................73
2.7 Result calculations.................................................................................................... 74
2.8 Statistics calculation .................................................................................................77
2.9 Common variables.................................................................................................... 79
2.10 Data output .............................................................................................................80
2.10.1 Reports for the output at the end of a determination.......................................80
2.10.2 Display of titration curve................................................................................... 83
2.11 User name, key <USER> ......................................................................................84
2.12 TIP, Titration procedure........................................................................................... 85
2.13 Method memory, keys <USER METH> and <CARD> ........................................ 89
2.13.1 Key <USER METH>........................................................................................ 89
2.13.2 Key <CARD> ..................................................................................................91
2.14 Calibration data, key <CAL.DATA>.......................................................................94
2.15 Current sample data, key<SMPL DATA>.............................................................. 95
2.16 Silo memory for sample data.................................................................................. 96
2.17 Storing results and silo calculations ....................................................................... 99
2.17.1 Storing determination results ........................................................................... 99
2.17.2 Silo calculations .............................................................................................100
2.18 Manual dosing and preparation of titration burets ...............................................103
2.18.1 Manual dosing ...............................................................................................103
2.18.2 Preparation of titration burets, key <PREP>................................................. 103
799 GPT Titrino
Table of contents
3 Operation via RS232 Interface (green pages) ......................................................105
3.1 General rules .......................................................................................................... 105
3.1.1 Call up of objects............................................................................................. 106
3.1.2 Triggers............................................................................................................ 107
3.1.3 Status messages ............................................................................................. 108
3.1.4 Error messages ............................................................................................... 111
3.2 Remote control commands.................................................................................... 116
3.2.1 Overview .......................................................................................................... 116
3.2.2 Description of the remote control commands................................................. 143
3.3 Properties of the RS 232 Interface.......................................................................... 180
3.3.1 Handshake....................................................................................................... 180
3.3.2 Pin Assignment................................................................................................ 183
3.3.3 What can you do if the data transfer does not work?...................................... 185
4 Error messages, Troubleshooting .......................................................................187
4.1 Error and special messages................................................................................... 187
4.2 Diagnosis................................................................................................................ 193
4.2.1 General ............................................................................................................ 193
4.2.2 Procedure ........................................................................................................ 193
4.2.3 Equipment required ......................................................................................... 194
4.2.4 Diagnosis steps ............................................................................................... 194
4.3 Initialize RAM .......................................................................................................... 205
4.4 Releasing a locked spindle with inserted Exchange Unit....................................... 206
5 Preparations .........................................................................................................207
5.1 Setting up and connecting the instruments ........................................................... 207
5.1.1 Titrino with Stirrer or Titration Stand................................................................. 207
5.1.2 Titrino with external burets ............................................................................... 208
5.1.3 Connection of a printer .................................................................................... 209
5.1.4 Connection of a balance.................................................................................. 210
5.1.5 Connection of a Sample Changer ................................................................... 211
5.1.6 Connection of a computer............................................................................... 212
5.1.7 Connection of a Remote Box........................................................................... 213
5.2 Connection of electrodes, preparing titration vessel.............................................. 216
6 Appendix ...............................................................................................................219
6.1 Technical specifications ......................................................................................... 219
6.2 Pin assignment of the "Remote" socket.................................................................. 222
6.2.1 Lines of the "Remote" socket during the titration............................................. 224
6.2.2 Possible configurations of the activate pulse in SET, KFT and CAL ............... 225
6.3 Titrino validation...................................................................................................... 226
6.3.1 Electronic tests ................................................................................................ 226
6.3.2 Wet tests .......................................................................................................... 226
6.3.3 Maintenance and adjustment of the Titrino ..................................................... 226
6.4 Warranty and conformity ........................................................................................ 227
6.4.1 Warranty........................................................................................................... 227
6.4.2 EU Declaration of conformity........................................................................... 228
6.4.3 Certificate of Conformity and System Validation ............................................. 229
6.5 Scope of delivery and ordering designations......................................................... 230
Index.........................................................................................................................233
799 GPT Titrino
1.1 Instrument description
1 Introduction
1.1 Instrument description
The 799 GPT Titrino is an all-purpose titrator with LCD graphical display. Titration curves
can be observed in real-time. The 799 GPT Titrino controls up to three dosing units for
complex titrations.
Titration modes of the 799 GPT Titrino are constant or – depending on the titration curve –
variable dosing of the titration reagent, Endpoint- and Karl-Fischer-Titration. In addition
the 799 GPT Titrino is able to serve as a sensor controlled dosing unit, with the controlled
variable fixed, respectively swept on a linear ramp during the dosing.
The operator is almost free to define his titrations. All operating modes of the Titrino can
be combined to perform extensive analytical sequences. The 799 GPT Titrino provides the
opportunity to store, transfer and upload applications and results via memory card.
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.
799 GPT Titrino
1
1.2 Controls and parts
1.2 Controls and parts
Front view of instrument:
1 Exchange Unit
2 Display
3 Setting of display contrast
4 Opening for the memory
card
5 Controls the dosing rate
during manual dosing with
<DOS> and subsequent
filling
6 Control keys and indicator
lamps on the Titrino
Key < > Power switch
Key < > Switching stirrer ON/OFF
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 (5).
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:
"COND." Lamp flashes when conditioning is performed and the titra-
tion vessel is still wet. It is on if conditioning is ok.
"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.
799 GPT Titrino
2
1.2 Controls and parts
Rear view of instrument:
7 RS232 interfaces
2 separate interfaces
for the connection of
printer, balance, and
computer
8
Remote lines
(input/output)
for the connection of
the Remote Box,
Sample Changers,
robots etc.
9 Connection of electrodes and temperature sensor
• 2 high-impedance measuring inputs for pH and U measurements. They can ei-
ther be used separately or for differential potentiometry, see page 216.
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, e.g. KF electrode
• 1 measuring input for PT100 or Pt1000 temperature sensor
10 Connection for separate keypad
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
Connection for external dosing units D1 and D2
685 Dosimats or 700 Dosinos
13
Connection for stirrer
728 Magnetic Stirrer, 802 Rod Stirrer, 703 or 727 Ti Stand
Supply voltage: 10 VDC (I ≤ 200 mA)
14 Rating plate
with fabrication, series and instrument number
799 GPT Titrino
3
2.1 Keypad
2 Manual operation
2.1 Keypad
CONFIG Configuration.
PARAM Parameters.
SMPL DATA Sample data.
STATISTICS ON/OFF switching of statistics calcula-
tions of consecutive determination, see
page 77.
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 96.
PREP Preselection of dosing units, see page
103.
CAL.DATA Calibration data, see page 94.
CARD Management of memory card, see
page 91.
C-FMLA Calculation values, see page 76.
DEF Formulas, data output, sequence for
TIP, see page 74ff.
USER METH Management of internal method mem-
ory, see page 89.
PRINT Printing of reports, see page 80.
REPORTS Result output.
MODE Mode selection, see page 14.
USER User name, see page 84.
CURVE Switching result/curve display.
←,→ Selection of special values (dialog
marked with ":")
↑,↓ Cursor key for navigation.
CLEAR Clears values, set special values.
ENTER Stores values.
The third functions (inscriptions in the triangle) on the keys of the keypad are used for
formula entry, see page 74.
STOP Stops methods.
QUIT Quits inquiries, waiting times, printing.
START Starts methods.
799 GPT Titrino
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2.2 Principle of data input
2.2 Principle of data input
• If you press a key you will find a group of inquiries in
the display.
configuration
>monitoring
>peripheral units
>auxiliaries
>RS232 settings COM1
>RS232 settings COM2
>common variables
>prep.dosing elements
configuration
>peripheral units
send to COM1: IBM
send to COM2: IBM
man.reports to COM: 1
balance: Sartorius
stirrer control: OFF
remote box: OFF
configuration
>monitoring
>peripheral units
>auxiliaries
>RS232 settings COM1
>RS232 settings COM2
>common variables
>prep.dosing elements
Example key <CONFIG>:
In the first line you see where you are: You pressed
key <CONFIG> and you are now in the inquiries
"configuration".
• The cursor is inverted. In our example the cursor is
on the inquiry ">monitoring". You can move the cursor up and down with keys <↑> and <↓>.
• If a dialog text is marked with ">", it contains a
group of inquiries itself. You go to this group pressing <ENTER>.
Example inquiries of "peripheral units":
The first two lines indicate again where you are.
Then you find the inquiries.
If a dialog text of an inquiry is marked with ":", you
can select a value with keys <←> and <→> (forward/backward).
• A value is stored with <ENTER> and the cursor
moves to the next inquiry.
• With key <QUIT> you move one level up, in our ex-
ample you go back to ">peripheral units".
If you press <QUIT> once more you quit the inquiries in "configuration" altogether.
• If you can scroll, ↓ or ↑ appear in the right lower or
upper corner of the display.
799 GPT Titrino
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2.3 Text input
2.3 Text input
user methods
>store method
method name: ********
<CLEAR>
REPORTS
ABC
.
user methods
>store method:
method name:
ABCDEFGHIJKLMNOPQRSTUVWXYZ
abcdefghijklmnopqrstuvwxyz
µ°!"#$&'()*+,-./ 0123456789
<QUIT>
user methods
>store method
method name: Text
<ENTER>
Example storing a method:
• Press key <USER METH>.
Place the cursor to ">store method" 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 <ABC>.
You can now select the desired character by means
of the cursor keys, then confirm this character. 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>.
• 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
<ABC>.
3. <CLEAR> now deletes the characters one by
one or you can add additional characters.
4. If your text is complete, leave the text writing
mode with <QUIT> and confirm the text with
<ENTER>.
799 GPT Titrino
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2.4 Configuration, key <CONFIG>
2.4 Configuration, key <CONFIG>
CONFIG
configuration
>monitoring
>peripheral units
>auxiliaries
>RS232 settings COM1
>RS232 settings COM2
>common variables
>prep.dosing element
>monitoring
validation: OFF
time interval 365 d
time counter 0 d
calibration: OFF
Key <CONFIG> serves to enter device specific data.
The set values apply to all modes.
monitoring:
Monitoring of instrument validation, pH calibration, service interval and printout of diagnostic report.
peripheral units:
Selection of printer, balance, stirrer control and COM
for manual report output.
auxiliaries:
e.g. setting of dialog language, date time, type of result
display.
RS232 settings COM1 and 2:
RS parameters for the COM's.
common variables:
Values of common variables.
prep.dosing element:
Parameters for the preparation of the dosing units.
The display texts of the Titrino are shown to the left.
The values are the default values.
Monitoring functions
Monitoring the validation interval (ON, OFF)
Monitoring is carried out at the end of the titrations and
when the Titrino is switched on. If the monitoring
responds the message "validate instrument" appears.
The message vanishes with <CLEAR>. At the same
time the counter is reset to zero.
If "on" has been set:
Time interval for validation (1...9999 d)
see also page 225.
Time counter (0...9999 d)
Counts the number of days since the last time the
counter was reset.
Monitoring the pH calibration interval (ON, OFF)
Monitoring is carried out at the end of the titrations and
when the Titrino is switched on if the measuring input
has a current calibration date. If the monitoring
responds the message "calibrate electrode" appears.
The counter will be reset to zero on the next pH
calibration of this input.
799 GPT Titrino
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2.4 Configuration, key <CONFIG>
meas.input: 1
time interval 7 d
time counter 0 d
service: OFF
next service YYYY-MM-DD
system test report: OFF
>peripheral units
send to COM1: IBM
send to COM2: IBM
man.reports to COM: 1
balance: Sartorius
If "on" has been set:
Measuring input (1, 2, diff.)
Time interval for validation (1...9999 d)
Time counter (0...9999 d)
Counts the number of days since the last time the
counter was reset.
Monitoring the service interval (ON, OFF)
Monitoring is carried out after the Titrino has been
switched on. If the monitoring responds the message
"Service is due" appears. The message vanishes with
<CLEAR>.
If "on" has been set:
Date of next service (YYYY-MM-DD)
System test report printout (ON, OFF)
With "on" the report of the system test is printed out
after the Titrino has been switched on, see also page
226.
Settings for peripheral units
Selection of printer (Epson, Seiko, Citizen, HP, IBM) at
the Titrino COM1
"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 or a data system.
COM of Titrino for the output of manually triggered
reports (1, 2, 1&2)
Manually triggered reports e.g. with <PRINT> .... .
Exception <PRINT><REPORTS>: These reports are
outputted on the COM as defined in the method.
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, and 016
interfaces
Mettler AT: Model AT
AND: Models ER-60, 120, 180, 182, FR-200, 300
and FX-200, 300, 320
Precisa: Models with RS232C interface
799 GPT Titrino
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2.4 Configuration, key <CONFIG>
stirrer control: OFF
remote box: OFF
keyboard: US
barcode: input
>auxiliaries
dialog: english
date 2001-09-14
time 08:13
run number 0
auto start OFF
Automatic switching ON/OFF of the stirrer in the titration
sequence (ON, OFF)
If stirrer control is ON, the stirrer will be switched on at
the beginning and switched OFF at the end of a determination. For SET and KFT with conditioning the
stirrer will be switched off in the inactive state.
In the modes MEAS, CAL, DOS, and TIP the stirrer is
not switched automatically.
For stirrer control the red switch on the stirrer unit must
be ON.
Connection of a remote box (on ,OFF)
To the remote socket for PC keyboard and barcode
reader, see page 212.
If "on" has been set:
Type of PC keyboard (US, German, French, Spanish,
Swiss.)
The PC keyboard is used as an input aid, see page
214.
Target for barcode reader (input, method, id1, id2, id3,
smpl size)
The barcode reader is used as an input aid, see page
213.
Input: The barcode string goes to the entry field in
which the cursor is currently located.
Method: The barcode string goes to the entry field
"Methods" in the silo memory.
Id1: The barcode string goes to the entry field
"Id1". (Similar for Id2 and Id3.)
Smpl size: The barcode string goes to the entry field
"smpl size".
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.
799 GPT Titrino
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2.4 Configuration, key <CONFIG>
start delay 0 s
result display: bold
dev.label.
program 799.0010
>RS232 settings COM1
baud rate: 9600
data bit: 8
stop bit: 1
parity: none
handshake: HWs
>common variables
C30 0.0
etc.
>prep.dosing elements
power ON prep: OFF
report: OFF
Start delay (0...999 999 s)
Delay time after start of methods. Abort start delay time
with <QUIT>.
Type of result display at the end of the determination
(bold, standard)
bold: The calculated results are displayed in bold
characters.
standard: Displays the whole information, e.g. results,
endpoints, messages etc.
Individual identification of devices (up to 8 ASCII
characters)
Will be printed in the result report, see page 81.
Display of program version
Settings of RS232 interface
see also page 180. Identical for COM2.
Baud rate (300, 600, 1200, 2400, 4800, 9600, 19200,
38400, 57600, 115200)
Data bit (7, 8)
Stop bit (1, 2)
Parity (even, odd, none)
Handshake (HWs, SWline, SWchar, none)
see page 180.
Values of the common variables
±
Common variables C30...C39 (0..
999 999)
The values of all common variables are displayed. For
creating of common variables see page 79.
Preparation of titration burets, "prep" and "empty"
see also page 103
Warning after power ON (ON, OFF)
If this function is on, a warning appears after switching
on the Titrino, that a preparation should be executed.
Report of prep (ON, OFF)
With ON, a report will be printed automatically after
prep. The report is outputted on the COM which is
given for manual reports.
799 GPT Titrino
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2.4 Configuration, key <CONFIG>
dos.element: internal D0
warn.interv.DX OFF min
dos.drive: Dosimat
volume DX 3.5 ml
cycles DX 2
dos.rate max. ml/min
fill rate max. ml/min
outlet: tip
len.dos.tub.DX 40.0 cm
diam.dos.tub.DX 2.0 mm
len.asp.tub.DX 25.0 cm
diam.asp.tub.Dx 2.0 mm
dos.rate max. ml/min
fill rate max. ml/min
Selection of the dosing element (internal D0, external
D1, external D2)
internal D0: buret of the Titrino
external D1/2: buret D1, D2, resp.
Warning interval for prep (5...9999 min, OFF)
Selection of the type of dosing element (Dosimat,
Dosino)
The internal buret D0 reacts like a "Dosimat".
Parameters for the internal buret and for
Dosimats:
Volume, that will be dosed with the preparation (0...99
999.99 mL)
Number of cycles (1...9)
Dosing rate (0.01...150 mL/min, max.)
Filling rate (0.01...150 mL/min, max.)
Parameters for Dosinos:
Location where the liquid will be expelled (tip, flask)
With "flask" the reagent will be re-expelled into the
bottle. In this case, it is possible that the titer will be
changed!
The next 4 entries serve to calculate the volumes which
will be expelled in prep:
Length of the dosing tube (1...999.9 cm)
Diameter of the dosing tube (0.1...9.9 mm)
Length of the aspirating tube (1...999.9 cm)
Diameter of the aspirating tube (0.1...9.9 mm)
Dosing rate (0.01...150 mL/min, max.)
Filling rate (0.01...150 mL/min, max.)
799 GPT Titrino
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2.4 Configuration, key <CONFIG>
Settings with key <CONFIG> and power ON
Proceed as follows:
1. Switch the Titrino OFF.
2. Press <CONFIG> and keep it pressed during switching the Titrino ON.
The display shows the following:
Setup
>lock
>curve
lock:
Locking keys <CONFIG>, <PARAM> and <SMPL
DATA>, and the functions "recall method", "store
method" and "delete method" of the internal method
memory in the Titrino.
curve:
Changes the appearance of the curve printout.
>lock
<configuration>: OFF
<parameters>: OFF
<smpl data>: OFF
recall method: OFF
store method: OFF
delete method: OFF
lock
"ON" means that the corresponding function is not
accessible anymore.
The corresponding key is locked.
The corresponding function in the internal method
memory of the Titrino is locked.
799 GPT Titrino
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2.4 Configuration, key <CONFIG>
>curve
grid: ON
frame: ON
scaling: Full
width 0.75
length 0.1
curve
The settings are valid for COM1 and COM2.
If you change the printer type, the following settings are
initialized according to the printer.
Grid drawing (ON, OFF)
Frame drawing (ON, OFF)
Type of scaling (Full, Auto)
Full: The scaling goes from the greatest to the smallest
value.
auto: The scaling from tick to tick, e.g. the
smallest/greatest values lie in between the first/last tick.
Width (0.2...1.00)
1 is greatest width. If you set 1 you may loose the label
at the right margin.
Length (0.01...1.00)
Volume axis
Curve length per cylinder volume
0.01 100 cm
0.1 10 cm
0.5 2 cm
1 1 cm
Time axis:
Curve length
0.01 100 cm
0.1 10 cm
0.5 2 cm
1 1 cm
799 GPT Titrino
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2.5 Selection of the mode, key <MODE>
2.5 Selection of the mode, key <MODE>
MODE
;
–
mode
mode: DET
measured quantity: pH
Press key <MODE> until the desired mode is
displayed and confirm with <ENTER>.
Select the measured quantity pH, U, Ipol, Upol, (T) with
<←> or <→> 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.
• KFT: Karl Fischer Titration, the determination of
water content.
• STAT: Keeping a measured value constant, i.e. pH-
STAT.
• DOS: Dosing function with volume, time, or rate
control.
• DOC: Dosing Controlled by a measured value
gradient.
• 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 85.
You will find a survey of the modes in the short
Instructions for use.
799 GPT Titrino
14
2.6 Parameters, key <PARAM>
2.6 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 and KFT
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.
2.6.1 Parameters for DET and MET
parameters
>titration parameters
>stop conditions
>statistics
>evaluation
>preselections
>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 page 77.
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 21.
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 21.
799 GPT Titrino
15
2.6 Parameters, key <PARAM>
dos.rate max. ml/min
**titr.
signal drift 50 mV/min
**titr.
equilibr.time 26 s
**titr.
start V: OFF
start V 0.0 ml
factor 0
dos.rate max. ml/min
**titr.
Dosing rate for volume increments (0.01...150 mL/min,
max.)
<CLEAR> sets "max.".
The maximum rate depends on the Exchange Unit:
Exchange Unit max.
5 mL 15 mL/min
10 mL 30 mL/min
20 mL 60 mL/min
50 mL 150 mL/min
Drift criterion for measured value acquisition. (input
range depends on the measured quantity:
pH, U, Ipol: 0.5...999 mV/min, OFF
Upol: 0.05...99.9 µA/min, OFF)
<CLEAR> sets "OFF".
This type of measured value acquisition is often called
an equilibrium titration.
"OFF" means that the measured value is acquired after
an equilibration time. This may be useful for slow
titration reactions or when the response of the
electrode assembly is slow.
Waiting time for measured value acquisition. (0...9999 s,
OFF)
<CLEAR> sets "OFF".
If no new equilibration time has been entered, the
Titrino calculates an equilibration time appropriate to
the drift, see page 20. The measured value is acquired
as soon as the first criterion (drift or time) has been
met.
Type of start volume (OFF, abs., rel.)
"OFF": start volume switched off
"abs": absolute start volume in mL
"rel.": relative start volume to sample size.
If "abs." is set:
Absolute start volume (0...999.99 mL)
If "rel." is set:
±
Factor for relative start volume (0...
Calculated as: start V (in mL) = factor
999 999).
∗sample size
Dosing rate for start volume (0.01...150 mL/min, max.)
<CLEAR> sets "max.".
Maximum rate depends on the Exchange Unit:
Exchange Unit max.
5 mL 15 mL/min
10 mL 30 mL/min
20 mL 60 mL/min
50 mL 150 mL/min
799 GPT Titrino
16
2.6 Parameters, key <PARAM>
pause 0 s
**titr.
dos.element: internal D0
meas.input: 1
I(pol) 1 µA
U(pol) 400 mV
electrode test: OFF
temperature 25.0 °C
>stop conditions
stop V: abs.
**titr.
stop V 99.99 ml
**titr.
factor 999999
**titr.
Waiting time (0...999 999 s)
Waiting time, e.g. for equilibration of the electrode after
the start or reaction time after dosing of start volume.
The pause can be aborted with <QUIT>.
Selection of the dosing element (internal D0, external
D1, external D2)
internal D0: internal buret of the Titrino
external D1/2: buret D1, D2, resp.
Measuring input for pH and U (1, 2, diff.)
Request for measuring input for pH and U.
Measuring input 1 or 2 or differential amplifier;
connection of electrodes, see page 215.
With polarized electrodes, instead of the measuring
input the
polarization current (-127...127 µA)
or the
polarization voltage (-1270...1270 mV, in steps of 10
mV)
is inquired.
Electrode test (OFF, ON)
Test for polarized electrodes. Performed on
changeover from the inactive standby state to a
measurement. "OFF" means that the test is not
performed.
Titration temperature (-170.0...500.0 °C)
The temperature is continuously measured if a T
sensor is connected. This parameter is used for
temperature compensation in pH titrations.
Stop conditions for the titration
If several stop conditions have been set, the criterion
which is met first applies.
Type of stop volume (abs., rel., OFF)
"abs.": absolute stop volume in mL.
"rel.": relative stop volume to sample size.
"OFF": stop volume switched off. Stop volume is not
monitored.
If "abs." is set:
Absolute stop volume (0...9999.99 mL)
If "rel." is set:
±
Factor for relative stop volume (0...
Calculated as: Stop V (in mL) = factor
999 999)
∗sample size
799 GPT Titrino
17
2.6 Parameters, key <PARAM>
stop pH OFF
**titr.
stop EP 9
**titr.
filling rate max. ml/min
**titr.
>evaluation
EPC 5
EP recognition: all
low lim.1 pH -20.00
up lim.1 pH 20.00
Stop at measured value (input range dependent on
measured variable:
±
pH: 0...
U, Ipol: 0...
Upol: 0...
20.00, OFF
±
2000 mV, OFF
±
200.0 µA, OFF)
<CLEAR> sets "OFF".
"OFF" means that the criterion is not monitored.
Stop after a number of EP's have been found (1...9,
OFF)
<CLEAR> sets "OFF".
"OFF" means that the criterion is not monitored.
Filling rate (0.01...150 mL/min, max.)
<CLEAR> sets "max.".
The maximum rate depends on the Exchange Unit:
Exchange Unit max.
5 mL 15 mL/min
10 mL 30 mL/min
20 mL 60 mL/min
50 mL 150 mL/min
EP evaluation/recognition
See page 21 ff.
Equivalence point criterion (input range depends on
mode.
For DET:
0...200
For MET:
pH: 0.10...9.99
U, Ipol: 1...999 mV
Upol: 0.1...99.9 µA)
Threshold for the size of the jump, see page 23.
Recognition of EP's which fulfill the EP criterion. (all,
greatest, last, window, OFF)
Selection of equivalence point recognition:
"all": All equivalence points are recognized.
"greatest": Only the greatest (steepest) equivalence
point is recognized.
"last": Only the last equivalence point is
recognized.
"window": Only EP's in specified windows are
recognized.
"OFF": Evaluation switched off.
If "window" is selected, lower and upper limits of
windows are inquired.
Lower limit of window 1
and
upper limit of window 1
(Input ranges for both inquiries depend on the
measured quantity):
pH: 0...±20.00, OFF
U, Ipol: 0...±2000 mV, OFF
Upol: 0...±200.0 µA, OFF)
799 GPT Titrino
18
2.6 Parameters, key <PARAM>
fix EP1 at pH OFF
pK/HNP: OFF
>preselections
req.ident: OFF
req.smpl size: OFF
limit smpl size: OFF
low lim. 0.0
up lim. 999999
activate pulse: OFF
<CLEAR> sets "OFF".
Only equivalence points are recognized which lie within
the set lower and upper limits. The equivalence point
numbering is defined with the windows, see page 23.
Window inquiries continue until the lower limit is set to
"OFF". Up to 9 possible windows.
Always set both limits to
≠ OFF for a valid window.
Interpolation of volumes at fixed times (input range
depends on the measured quantity:
pH: 0...±20.00, OFF
U, Ipol: 0...±2000 mV, OFF
Upol: 0...±200.0 µA, OFF)
<CLEAR> sets "OFF".
If a fix end point has been set, the volume value for the
input measured value is interpolated from the curve,
see also page 24. The volume values are available as
C5X.
Fix EP's are inquired until "OFF" is set. Up to 9 fix EP's.
Evaluation of pK or HNP (ON, OFF)
pK evaluation in case of pH titrations and half
neutralization potential for U, see page 24.
Preselections for the sequence
Request of identifications after start of titration. (id1,
id1&2, all, OFF)
After start, sample identifications can be inquired
automatically: Only id1, id1 & id2, all three id's or no
inquiries.
Request of sample size after start of titration (value, unit,
all, OFF)
"all" requests the value, then the unit.
Limiting value check for sample size (ON, OFF)
With "on" the error message "sample size out." appears
if the entry is outside the set limits. The limiting values
are shown in the display window.
The absolute value of the limit is checked during sample size input and during the calculation of the results.
If "on" has been set:
Lower limit for sample size (0.0...999 999)
Upper limit for sample size (0.0...999 999)
Pulse output on I/O line "activate" (L6, pin 1) of the
remote socket (ON, OFF)
see page 224.
799 GPT Titrino
19
2.6 Parameters, key <PARAM>
Titration sequence of DET and MET
<START>
(Activate pulse)
(Stirrer ON)
(Start delay)
(Request ident.)
(Request smpl size)
(Start conditions)
Titration:
Dispense increments
Acquire meas.values
Stop conditions
(Stirrer OFF)
Calculations
Data output
After the start, the activate pulse is outputted and the stirrer switched on.
The start delay time is waited off.
The sample identifications and the sample size are requested.
The start volume is dispensed (no meas.value acquisition)
and the pause is waited off.
During the titration the volume increments are dispensed
and after each increment a measured value is acquired.
Meas.values are either acquired drift controlled ("equilibrium titration") or a after a fixed waiting time. If you have
not intentionally changed the equilibration time, it is calculated according to the formula:
equilibr.time (in s)
The criterion (drift or equilibration time) which is first met
applies. This avoids "infinite" titrations. If the parameter
"signal drift" is set "OFF", the measured values are acquired after a fixed equilibration time.
The titration is terminated according to the first criterion
which is met.
The stirrer is switched off.
Evaluations and calculations are carried out.
Data are outputted.
150
=
+
+
0.01Drift
5
799 GPT Titrino
20
2.6 Parameters, key <PARAM>
Reagent feeding and EP evaluation of DET
The reagent feeding of DET is similar to the controlling, a human being would apply in
manually controlled titrations: Great volume increments are dosed far away from the EP,
small increments in the region of the equivalence point.
The size of the volume increments dosed by the Titrino is determined by the following
parameters:
meas.pt.density
The measuring point density is entered as a relative
value from 0...9. Input of a low number means small
volume increments, i.e. a large measuring point density
on the curve. A curve results which reproduces all fine
details. "Fine details", however, also include signal noise,
which can easily lead to unwanted equivalence points. A
high number, i.e. low measuring density, on the other
hand, allows a more rapid titration. The standard value of
4 is suitable for most cases.
If you work with small cylinder volumes (1 or 2 mL), a
small measuring point density may be advisable. In
these cases you should also lower the drift for
meas.value acquisition and set a higher EPC.
min.incr.
Defines the minimum possible increment. This minimum
increment is dosed at the beginning of the titration and
in the region of the equivalence point (for steep curves).
Use low minimum increments only, if small volumes of
titrant consumption are expected, e.g. in micro titrations;
otherwise unwanted equivalence points may arise. The
standard value of 10.0 µL is suitable for most cases.
EPC
The EP's are evaluated according to a special
METROHM procedure which is so sensitive that even
weak equivalence points are determined correctly.
Equivalence Point Criteria.
The
preset EPC is compared to the found ERC
(Equivalence point Recognition Criteria) for each
evaluated equivalence point. The size of the ERC is
displayed in the titration curve, see page 83. The ERC is
the first derivative of the titration curve overlaid with a
mathematical function so that small maxima become
higher and great maxima smaller. EP's whose ERC is
below the preset EPC will not be recognized. For most
cases the standard value of 5 is suitable. The evaluation
can be repeated at any time after the titration in a "dry
run" with changed evaluation criteria. The old titration
data are not deleted until a new titration is started.
799 GPT Titrino
21
2.6 Parameters, key <PARAM>
Reagent feeding and EP evaluation of MET
In monotonic titrations, the volume increment is constant over the whole titration curve.
V step
Volume increment.
A prerequisite for good accuracy is the correct size of
the volume increments. A good value is given by V step
= 1/20 V
increment size should always be between 1/10 V
1/100 V
(VEP = volume of the EP). In any case, the
EP
EP
; with steep jumps preferably in the region of
EP
and
1/100 and with flat jumps preferably in the region of 1/10.
The accuracy of the evaluation can not be increased by
dispensing small increments as the changes in the
measured value can then be of the same order of
magnitude as the noise. This can produce "ghost EP's"!
EPC
The EP's are localized with an algorithm which is based
on Fortuin and has been adapted by METROHM for
numeric procedures. (METROHM Bulletin 2
, No. 10,
1971). Here, the greatest change in the measured value
is sought (∆
). The exact equivalence point is determined
n
with an interpolation factor, which depends on the delta
values before and after ∆
V
: EP volume
EP
V
: Total dispensed volume before ∆n
0
:
n
V
= V0 + ρ ∆V
EP
∆V: Volume increment
ρ : Interpolation factor (Fortuin)
Equivalence Point Criteria.
The
preset EPC is compared to the found ERC
(Equivalence point Recognition Criteria) for each
evaluated equivalence point. The size of the ERC is
displayed in the titration curve, see page 83. ERC is the
sum of the measured value changes before and after the
break:
∆
+∆
n-2
+∆n+∆
n-1
n+1
+∆
n+2
(In certain cases there are only 3 or 1 summand).
EP's whose ERC is below the preset EPC will not be
recognized. For most titrations the standard value is
suitable.
The evaluation can be repeated at any time after the
titration in a "dry run" with changed evaluation criteria.
The old titration data are not deleted until a new titration
is started.
799 GPT Titrino
22
2.6 Parameters, key <PARAM>
V
V
EP recognition criteria for DET and MET
The parameter "EP recognition" offers you a range of possibilities to ensure selection of
the EP you are interested in: If the desired jump is very large, you can select the "greatest"
jump (with DET the steepest jump will be evaluated). Thus you always obtain just one EP
per titration (EP1).
If you wish to determine the sum of different components (e.g. acid or base numbers), the
"last" jump can be the correct one.
And finally you can set a "window" for each expected EP.
EP windows
EP windows are used
• to suppress disturbing influences and EP's which are not needed.
• to increase the liability for the calculation of the results. The EP windows make an
unequivocal assignment of the EP's possible: per window one EP is recognized; the
numbering of EP's is defined by the windows so that even if EP's are missing, the
calculations are still performed with the correctly assigned EP volumes.
An EP window defines the range in which an EP is expected. EP's outside these ranges
are not recognized. Windows are defined on the measured value axis.
U/mV
2 EP's are recognized. Their
numbering is defined by the windows:
EP window 2
EP window 1
EP 1
EP 2
Window 1
Window 2
If more than 1 EP is expected, a
⇒ EP1
⇒ EP2
window must be set for each EP.
Windows must not overlap. They may
only touch each another.
/mL
U/mV
Rule: If there are more than 1 EP in a
upper lim. 1
window, the first jump is recognized as
EP1, the second is not recognized.
+ EP window 1
EP1 is marked as EP1 + to indicate
that more than one EP has been found
in the window
EP 1
lower lim. 1
/mL
799 GPT Titrino
23
2.6 Parameters, key <PARAM>
Fix EP's
Fix EP's allow determination of the associated volume value for every inputted measured
value on the titration curve. This function is useful for performing standard methods such
as TAN/TBN determinations. For the evaluation of fix EP's, the pH calibration is advisable.
The volume values of the fix EP's are available for the calculation as C5X:
Fix EP1
⇒ C51
:
Fix EP9
⇒ C59 Maximum 9 fix EP's are possible.
pK and HNP evaluation
The following relation (Henderson-Hasselbach), derived from the law of mass action,
exists between the activities of a conjugate acid-base pair in aqueous solutions:
When the activities a
pH = pK + log (a
= aA, then pH = pK is valid. This value corresponds to the pH at
B
B/aA
)
the half neutralization point and can be taken from the titration curve. For pK determinations, a careful pH calibration is necessary.
The pK value determined is an approximate value owing to the fact that the ionic strength
of the solution has not been taken into account. For more exact values, titrations must be
performed with decreasing ionic strength and the results extrapolated to zero ionic
strength.
The evaluation of pK's in aqueous solutions is limited to
pK>3.5 due to the leveling effect of strong acids in aqueous solutions
pK<10.5 because for weaker acids no inflection points can be found aqueous
solutions.
pK evaluation for polybasic acids and for acid mixtures is also possible.
In non-aqueous solutions, the half neutralization potential (HNP) is often used instead of
pK. The HNP is evaluated accordingly.
A start volume must be smaller than half of the equivalence point volume of the first EP.
The pK/HNP values are available for calculation as C6X.
Minimum/maximum evaluation
Volumes at minimum or maximum voltage values are extrapolated. These volumes are
accessible as variables C49 and C48 resp. and can be used in formulas.
799 GPT Titrino
24
2.6 Parameters, key <PARAM>
2.6.2 Parameters for SET
parameters
>SET1
>SET2
>titration parameters
>stop conditions
>statistics
>preselections
>SET1
EP at pH OFF
**titr.
dynamics OFF
**titr.
max.rate 10.0 ml/min
**titr.
SET1, SET2:
Control parameters for EP1 and EP2.
titration parameters
are valid for the global titration sequence.
stop conditions:
Parameters for the termination of the titration.
statistics:
Calculation of mean values and standard deviation,
see page 77.
preselections:
ON/OFF of various auxiliary functions such as automatic requests after the start and activate pulse.
Control parameters for EP1 or EP2, resp.
Preset EP1 (input range depends on the measured
quantity:
pH: 0...±20.00, OFF
U, Ipol: 0...±2000 mV, OFF
Upol: 0...±200.0 µA, OFF)
<CLEAR> sets "OFF".
If EP1 is "OFF", no further inquiries under SET1 appear.
Distance from EP where constant dosing should stop
and controlling begins. (control range, input range
depends on the measured quantity:
pH: 0.01...20.00, OFF
U, Ipol: 1...2000 mV, OFF
Upol: 0.1...200.0 µA, OFF)
<CLEAR> sets "OFF".
"OFF" means largest control range, i.e. low titration.
Outside the control range, dispensing is performed
continuously, see also page 31.
Maximum dosing rate (0.01...150 mL/min, max.)
<CLEAR> sets "max.".
This parameter determines primarily the addition rate
outside the control range, see also page 31.
The maximum rate depends on the Exchange Unit:
Exchange Unit max.
5 mL 15 mL/min
10 mL 30 mL/min
20 mL 60 mL/min
50 mL 150 mL/min
799 GPT Titrino
25
2.6 Parameters, key <PARAM>
min.rate 25.0 µl/min
**titr.
stop crit: drift
**titr.
stop drift 20 µl/min
**titr.
t(delay) 10 s
**titr.
stop time OFF s
**titr.
>titration parameters
titr.direction: auto
pause 1 0 s
**titr.
start V: OFF
cond.
start V 0.0 ml
cond.
factor 0
cond.
Minimum dosing rate (0.01...999.9 µL/min)
This parameter determines the addition rate right at the
start and the end of the titration, see also page 31.
This parameter influences the titration speed and
therefore its accuracy very strongly: A smaller min.rate
results in a slower titration.
Type of stop criteria (drift, time)
Titration stops if EP is and stop drift is reached. (1...999
µL/min)
Titration stops if there is no dosing during t(delay).
(0...999 s, INF)
<CLEAR> sets "INF"
Switch off when the end point is reached and the set
time after the last dispensing has elapsed.
If "INF" is set, an inquiry regarding the stop time
appears.
If t(delay) is "INF"
Stop after a time (0...999 999 s, OFF)
<CLEAR> sets "OFF".
Stop after the set time after the start of the titration.
"OFF" means no stop, i.e. titration for an "infinitely" long
time.
General titration parameters
Direction is set automatically (+, -, auto)
auto: The direction is set automatically by the Titrino
(sign [U
- EP]).
first
+: Direction of higher pH, higher voltage (more
"positive"), larger currents.
- : Direction of lower pH, lower voltage, smaller
currents.
The titration direction is fixed if two EP's are set. In this
case, an input for titration direction has no meaning.
Pause 1 (0...999 999 s)
Waiting time before start volume, e.g. for equilibration
of the electrode after the start. The waiting time can be
aborted with <QUIT>.
Type of start volume (OFF, abs., rel.)
"OFF": start volume switched off
"abs.": absolute start volume in mL
"rel.": relative start volume to sample size.
If "abs." is set:
Absolute start volume (0...999.99 mL)
If "rel." is set:
Factor for relative start volume (0...±999 999).
Calculated as: start V (in mL) = factor∗ sample size
799 GPT Titrino
26
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