Lovibond SensoDirect pH200 User manual

SensoDirect pH200
pH-/Redox-/Temperature Meter
Operating instructions
Meas Cal
Hold Rcl Store
On
Off Menu
%
°C
pH
Rel mV
mV
ATC OK CAL
MEAS
HOLD
°F
°C
GB

Declaration of CE-Conformity
The manufacturer: Tintometer GmbH
Schleefstraße 8 a
44287 Dortmund
Deutschland
declares that this product
Product name: SensoDirect pH200
with all optional items conforms to the following regulations:
EMC EN 55 022 : 6 / 1993 class B
EN 50 082-1 (EN 61000-4-6,
EN 61000-4-4, EN 61000-4-3,
EN 61000-4-2)
The product conforms to the regulations of the EMC Directive
89/336/EEC and 73/23/EEC.
Dortmund, March 12, 2003
Cay-Peter Voss,
Managing Director

Table of Contents Page
1. Scope of delivery .............................................................. 4
2. System description ........................................................... 4
3. Connections ..................................................................... 5
4. Display ............................................................................. 7
5. Keypad ............................................................................ 7
6. Start up ............................................................................ 8
7. Measurement ................................................................... 9
8. Configuration of the unit ................................................. 11
8.1 Selection of measuring function [pH] – [mV] – [Rel mV] ... 11
8.2 Calibration: selection of calibration ................................. 12
8.3 Display of electrode status.............................................. 12
8.4 Selection of temperature unit °C /°F ............................... 14
8.5 Power off: automatic unit switch-off ................................ 14
9. Calibration of pH measurement ...................................... 14
9.1 Starting calibration: Press [CAL] key ............................... 16
9.2 Selecting buffer solutions................................................ 16
9.3 Calibration point 1: ‘CAL. 1’ ........................................... 17
9.4 Calibration point 2: ‘CAL. 2’ ........................................... 18
9.5 Calibration point 3: ‘CAL. 3’ ........................................... 20
10. Result memory ............................................................... 21
10.1 Storing results ................................................................ 21
10.2 Displaying stored results ................................................. 21
10.3 Deleting stored results .................................................... 22
11. Error messages and troubleshooting .............................. 22
12. Technical data ................................................................ 25
13. Accessories .................................................................... 27
14. Assembling Carrying strap .............................................. 27

4
1. Scope of delivery
Standard:
• pH Meter
• Batteries, 4 x AA 1,5 V cells
• Operating instructions
• Carrying strap
Set:
• pH Meter
• Batteries, 4 x AA 1,5 V cells
• pH/Temperature sensor
• Standard buffer solutions, each 90 ml pH 4.00/7.00/
10.00
• Carrying case
• Operating instructions
• Carrying strap
2. System description
The system is a sturdy, water-tight handheld meter
designed for daily measurements in the area of field or
laboratory analysis.
It is used to measure redox voltage and temperature
in the field of environmental analysis as well as for ap-
plications in the food and chemical industries.
The system complies with the requirements in EN
60529 relating to protection class IP67 and water-
proof/dustproof properties.

5
The permanent protective plating on the unit serves
not just as impact protection but also as a storage
compartment for the electrode and as an anti-slip de-
vice when the meter is used in an upright position.
Microprocessor technology and 4 x AA 1,5 V batte-
ries allow unit operation without battery change for
15,000 hours or more.
A "Low Bat” indicator in the display shows the user
when it is time to change the batteries.
The required temperature compensation for the sy-
stem is performed automatically (ATC) following con-
nection of a temperature sensor or via manual input
via the touch-sensitive film keypad. The unit automati-
cally identifies Pt1000 and NTC 30 kOhm sensors.
The AUTO HOLD feature enables the user to identify
stable results and call them up on the display.
The MEAS function is the standard continuous measu-
ring mode for pH levels or redox voltages.
pH calibration of the system is via an integrated auto-
matic buffer recognition feature.
The temperature characteristics of the Tintometer stan-
dard buffer solutions and the reference buffer soluti-
ons specified in DIN 19266 are stored in the unit and
are used for automatic calibration of the system when
selected.
It is additionally possible to enter some of the buffer
data into the unit manually.
Calibration is performed optionally at 3 points, 2 points
or 1 point.
A sensor evaluation is automatically shown in the dis-
play (or can be called up via the menu) after each ca-
libration.

6
An internal memory for 20 results is integrated in the
unit as standard. The memory stores location, result
and temperature.
The memory is called up via the display.
3. Connections
Temperature sensor “T”, 4mm
1-pin
Temperature sensor “REF”
and separately routed reference
electrode, if present, 4mm 1-pin
pH or redox electrode, HF soc-
ket in acc. with DIN 19262
T REF
%
°C
pH
Real mV
mV
ATC O CAL
MAX
MEAS
MIN
HOLD
°F
°C
MeasCAL
Hold KClStore
On
Off Menu
%
°C
pH
Rel mV
mV
ATC OK CAL
MEAS
HOLD
°F
°C
Meas Cal
Hold Rcl Store
On
Off Menu
123
456
789

7
%
°C
pH
Rel mV
mV
ATC OK CAL
MEAS
HOLD
°F
°C
Meas Cal
Hold Rcl Store
On
Off Menu
4. Display
5. Keypad
Meas Continuous measurement,
(standard setting)
Hold Auto Hold: automatic retaining
of stable result
on/off On/Off
[▲] [▼] Leaf through menu or memory,
manual temperature setting
Rcl Display of stored results
Cal Calibration mode
Store Storage of current
result or acceptance of
unit configuration
Menu Unit configuration
Main display: Result or user prompt
[mV] Redox voltage, absolute
[Rel mV] Redox voltage, relative to the
hydrogen electrode (DIN 38404)
[pH] pH level
Secondary display: Result - temperature
or user prompt
[%] Percent (sensor evaluation)
[∆
!
] Warning index - battery/ one-point calibration
[°C,°F] Temperature unit
[ATC] Automatic temperature compensation
[OK] Stable measuring signal
[CAL] Calibration mode
[MEAS] Measuring mode - standard
[HOLD] Measuring mode - AUTO-HOLD

8
6. Start up
The unit is supplied with integrated batteries as stan-
dard and is therefore ready for immediate use.
You have to unscrew the unit to insert or change the
batteries. When inserting the batteries, ensure correct
polarity!
Screw the unit back together carefully without exer-
ting too much pressure on the gasket seal.
If the ∆
!
symbol appears together with “bAt” in the
lower section of the display, this means that the batte-
ries are nearly empty and need replacing.
However, the unit will continue to function for a certain
period of time. If “bAt” appears in the upper section of
the display, this means that the batteries are comple-
tely empty.
Displayed values in the event of cable break or if no
pH or redox electrode is connected:
If no electrode is connected or if the connecting cable
Remove
6 screws
4 x AA 1,5 V
Don`t
touch
Display

9
is defective, the display still shows pH or mV results.
However, these results are not valid results!
The electrode or temperature sensor must be plug-
ged in before the unit is switched on.
Switch the unit on via the [On/Off] key.
The system must be calibrated when the system is
started up (see Calibration).
Following measurement, please switch the unit off
using the [On/Off] key.
See the enclosed Operating Instructions for more de-
tailed information on storage and care of the electro-
des.
7. Measurement
Measuring mode MEAS
After the unit is switched on, it is automatically in the
standard measuring mode MEAS.
You can switch to the standard MEAS measuring mode
by pressing the [Meas] key.
The display shows the current, possibly still fluctua-
ting result and MEAS. If the result is stable, the [ok]
arrow appears in the display.
Measuring mode HOLD
Pressing the [Hold] key takes you into the AUTO HOLD
measuring mode.
In this mode, the recorded result is checked by the
system in line with the predefined stability criteria until
these criteria are met.
On
Off
Hold
Meas

10
The display shows Auto/Hold in alternating mode to-
gether with the result.
Once a stable reproducible value is present, the result
is shown permanently in the display (“frozen”).
The display also shows HOLD and the automatically
set or manually entered temperature.
If you press the [Hold] key again, the measuring cycle
starts anew and runs until the stability criteria are met.
Temperature measurement, automatic temperature
compensation (ATC)
During pH measurement and redox measurement (re-
lative to the hydrogen electrode [Rel mV]), it is neces-
sary to compensate for the temperature effect of the
electrode.
If a temperature sensor is connected, temperature
compensation is performed automatically (ATC = au-
tomatic temperature compensation).
The unit can automatically distinguish between a
Pt1000 and an NTC30kOhm temperature sensor.
The sensor type is displayed if you simultaneously press
the [Meas] and [Hold] keys.
If a temperature sensor is not connected, you must
manually enter the temperature of the medium to be
tested using the [▲] [▼]keys after switching on the unit
and confirm the value by pressing the [Store] key.
During the measurement process, you can change the
temperature value at any time using the [▲] [▼]keys.
In the HOLD measuring mode, a new Auto Hold mea-
surement is started automatically every time a change
is made.
Hold
+
Hold
Meas +

11
8. Configuration of the unit
To configure the unit, press the [Menu] key. The first
menu item appears.
If you press the [Menu] key again, the display jumps to
the next menu item.
You can set the various parameters using the [▲] [▼]
keys.
Press the [Store] key to store and conclude configura-
tion.
The unit then switches back to measuring mode.
You can terminate the configuration process by pres-
sing the [Meas] or [Hold] key.
Settings made up to this point are not stored.
The unit retains the previous settings.
8.1 Input: selection of measuring
function [pH] – [mV] – [Rel mV]
Select the desired measuring function using the [▲] [▼]
keys. The arrow in the display shows the selected
function.
• pH: pH measurement with pH electrode
• mV: redox measurement with redox electrode
• Rel mV: redox measurement with redox electrode.
The displayed value is converted to the
normal hydrogen system in temperature-
dependent mode (DIN 38404).
Menu
Store
+
+
Hold
Meas +

12
8.2 CAL = Calibration: selection of
calibration (only with pH function)
You can choose between 1, 2 and 3-point calibration.
1-point calibration:
Calibration of the pH electrode is performed at a ran-
dom point.
The electrode slope is always based on the theoreti-
cal slope of -59.2mV/pH.
2-point calibration:
Calibration of the pH electrode is performed at two
points.
3-point calibration:
Calibration of the pH electrode is performed at three
points.
8.3 Display of electrode status
(only with pH function)
Indication of the electrode status that is computed
internally during every calibration depending on the
electrode used.
• 100% The electrode is in excellent condition.
• 30...90% The condition of the electrode is ade
quate.
• <30% The electrode is old or soiled.
If there is no improvement after you have cleaned and
recalibrated the electrode (see operating instructions
for electrode), you need to replace the electrode.
%

13
Percentage calculation of the electrode status is ba-
sed both on asymmetry potentials and on slopes (gra-
dient of the pH characteristic) of the electrode. The
electrode condition is then determined by the worst
result. The admissible characteristic data of the pH
electrodes are as follows:
Asymmetry potential of the electrode at 25°C in mV
Max. admissible range: +30...-30 mV
Optimum: 0 mV
Soiling of the electrode can have a major adverse ef-
fect on asymmetry.
[SL] = Slope of the electrode signal at 25°C in mV/pH
Admissible range: -62...-50 mV/pH
Optimum: -59,2 mV/pH
1-point calibration is always based on the optimum
theoretical value of –59.2mV/pH. The slope is not
shown in the menu.
For 2-point calibration, the slope is specified for the
entire measuring range.
For 3-point calibration, the slope is first displayed for
the lower, acid measuring range [SL. 1] and then for
the upper, basic range [SL. 2].

14
8.4 Selection of
temperature unit °C /°F
• °C All temperature values in degrees Celsius
• °F All temperature values in degrees Fahrenheit
(°C = 0.556*°F-17.8 or °F = 1.8*°C+32)
8.5 Power off: automatic
unit switch-off
If no key is pressed during the switch-off delay peri-
od, the unit switches off automatically after the selec-
ted time has run down.
The desired delay time is entered in minutes.
If P.oFF = oFF, automatic unit switch-off is inactive.
9. Calibration of pH measurement
The individual sensor characteristics of pH electrodes
are affected by ageing which causes fluctuations.
This is why, prior to measurement, it is important to
check the current system calibration using buffer so-
lutions to ensure optimum measuring results.
If the calibration deviates from the ideal setting by more
than a certain amount, you need to recalibrate the sy-
stem.
Buffer solutions are liquids that possess an exact, re-
producible pH level.
Calibration can be performed using buffers in the:

15
• Tintometer standard series (25°C): pH 4.00, pH
7.00 and pH 10.00
• DIN 19266 series (25°C):
pH 1.68 (A), pH 4.01 (C), pH 6.87 (D), pH 9.18 (F)
and pH 12.45 (G)
• or using any user-selectable buffers
The shelf life of buffer solutions is limited and is shor-
tened further by, among other things, inadequate cle-
aning and drying of the electrode prior to insertion.
This can lead to incorrect calibration! You should the-
refore always use fresh buffer solutions for calibration
wherever possible and clean the electrode using deio-
nised or distilled water!
Automatic temperature compensation for calibration
Both the pH electrode signals and the pH buffer valu-
es are temperature-dependent. If a temperature sen-
sor is connected, the temperature effect of the elec-
trode is compensated automatically during measure-
ment and calibration.
Otherwise, you need to enter the actual temperature
of the buffer as accurately as possible during calibrati-
on. If you use the Tintometer standard buffer series or
the DIN buffer series, the temperature effects of the
buffers are additionally compensated.
To ensure maximum precision of calibration in the event
of manual buffer selection, you should enter the pH
values of the buffers at the corresponding tempera-
ture.

16
Performing calibration
If you have not already done so, select the measuring
mode 'pH' (see Configuration) and ensure that (de-
pending on your requirements), 1-point, 2-point or 3-
point calibration is active in the configuration setting
Carefully remove the protective cap from the electro-
de.
Clean the electrode using deionised water and
dry carefully.
9.1 Starting calibration: Press [Cal] key.
‘CAL’ appears momentarily in the display.
You can terminate calibration at any time by pressing
the [Meas] key or [Hold] key. In this event, the previous
calibration setting is retained.
9.2 Selecting buffer solutions
‘buFF’ is shown in the main display.
You can choose between the various buffer series using
the [▲] [▼]keys.
You then confirm the selected buffer set by pressing
the [Store] key.
The following inputs are possible:
Tintometer standard series
Values at 25°C: 4.00pH, 7.00pH, 10.00pH
Store
+

17
DIN 19266 series
Values at 25 °C: 1.68pH(A), 4.01pH(C), 6.87pH(D),
9.18pH(F),12.45pH(G)
Manual buffer setting
If you want to use buffers other than those in the Tin-
tometer standard or DIN series, you can choose ma-
nual buffer adjustment here.
9.3 Calibration point 1: 'CAL. 1'
Insert the electrode and the temperature sensor (if
present) in buffer solution 1 (e.g. Tintometer standard
buffer solution pH 7.00) and swirl carefully.
In the case of manual buffer setting, [Pt.1] appears in
the secondary display.
You enter the pH value of the buffer solution using the
[▲] [▼]keys.
You then confirm the input by pressing the [Store] key.
When Tintometer standard and DIN series solutions
are used, the system automatically detects the pH
value of the solution.
[CAL.1] appears in the secondary display until the va-
lue is stable; the detected value is then automatically
stored .
You are then requested to perform the next calibration
step.
Store
+

18
Without temperature sensor:
manual input of temperature of solution 1
You can enter the actual temperature of the buffer so-
lution using the [▲] [▼]keys.
The value is stored when you press the [Store] key,
and the system shows the next calibration step.
In the case of 1-point calibration, the status of the elec-
trode is then displayed (only asymmetry potential, slo-
pe optimal = 59.2 mV/pH); the unit then switches to
the standard measuring mode MEAS.
After 1-point calibration, the ∆
!
signal is permanently
shown in the display.
The user should be aware that measuring errors can
occur with 1-point calibration, particularly with results
that are a long way from the calibration point.
2-point calibration is therefore always advisable.
Clean the electrode using deionised water
and dry carefully.
9.4 Calibration point 2: 'CAL. 2'
(only with 2-point and 3-point calibration)
Insert the electrode and the temperature sensor (if pre-
sent) in buffer solution 2 (e.g. Tintometer standard
buffer solution pH 4.00).
In the case of manual buffer setting, [Pt.1] appears in
the secondary display. You enter the pH value of the
respective buffer solution using the [▲] [▼]keys. You
then confirm the input by pressing the [Store] key.
When Tintometer standard and DIN 19266 series so-
°C
Store
+
Store
+

19
lutions are used, the system automatically detects the
pH value of the solution.
If the display flashes and switches between different
buffers, this means that no valid buffer has been de-
tected.
[CAL.2] appears in the secondary display until the va-
lue is stable; the detected buffer value is then automa-
tically stored.
You are then requested to perform the next calibration
step. In the case of 2-point calibration, the status of
the electrode is then displayed (asymmetry potential
and slope); the unit then switches to the standard
measuring mode MEAS.
Without temperature sensor: manual input
of temperature of solution 2
You can enter the temperature of the second buffer
solution using the [▲] [▼]keys.
The value is stored when you press the [Store] key,
and the status of the electrode is displayed.
Clean the electrode using deionised water
and dry carefully.
Store
+
°C

20
9.5 Calibration point 3: 'CAL. 3'
(only with 3-point calibration)
Insert the electrode and the temperature sensor (if pre-
sent) in buffer solution 3 (e.g. Tintometer standard se-
ries pH 10.00).
In the case of manual buffer setting, [Pt.1] appears in
the secondary display. You enter the pH value of buf-
fer solution 3 using the [▲] [▼]keys. You then confirm
the input by pressing the [Store] key.
When Tintometer standard and DIN 19266 series so-
lutions are used, the system automatically detects the
pH value of the solution.
If the display flashes and switches between different
buffers, this means that no valid buffer has been de-
tected.
[CAL.3] appears in the secondary display until the va-
lue is stable; the detected buffer value is then automa-
tically stored.
In the case of 3-point calibration, the status of the elec-
trode is then displayed (asymmetry potential and slo-
pe); the unit then switches to the standard measuring
mode MEAS.
Without temperature sensor: manual input
of temperature of solution 3
Store
+
°C