Biolin Scientific Sigma 702 Product information sheet

Sigma 702
User Manual
Original instructions
Force Tensiometer
MANUAL23834-4

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Table of Contents
1. INTRODUCTION 4
2. SAFETY 5
3. PHYSICAL DESCRIPTION 7
3.1 Measurement Unit 7
3.1.1 Main Body 7
3.1.2 Balance 7
3.1.3 Lifting System 7
3.1.4 Measuring stage 7
3.1.5 LCD Display 7
3.1.6 Manual Membrane Keyboard 8
3.2 Optional Accessories 9
3.2.1 Du Noüy Ring 9
3.2.2 Wilhelmy Plate 9
3.2.3 Density Probe 10
3.2.4 Thermostatic Vessel 10
3.3 Cleaning procedure 11
3.4 Maintenance 11
4. TECHNICAL SPECIFICATIONS 12
5. MEASUREMENT 13
5.1 Preparations for measurement 13
5.2 Measuring surface tension with a Du Noüy ring 14
5.2.1 Choosing a correction method: Huh-Mason or Zuidema-Waters 15
5.3 Measuring interfacial tension with a Du Noüy ring 16
5.3.1 Push Mode and normal (pull) mode 16
5.3.2 Measurement steps 16
5.4 Surface tension measurement with a Wilhelmy Plate 17
5.4.1 Steps for measurement 17
5.4.2 Taring modes: Wet Taring and Dry Taring 18
5.5 Density measurement 18
5.5.1 Density of a liquid 18
5.5.2 Density of a solid object 19
5.6 Collecting data to a PC 19

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5.7 Using the optional printer 20
6. CALIBRATION OF SIGMA 702 21
6.1 Calibration of the electromagnetic balance 21
6.1.1 Calibration procedure 21
6.1.2 Calibration result verification 21
6.2 Calibration of the density measurement system 22
7. TROUBLESHOOTING 23
8. CONTACT AND SUPPORT 24
9. EC DECLARATION OF CONFORMITY 25

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1.Introduction
The Sigma tensiometer system is a high performance tensiometer for the measurement of surface
or interfacial tension. The 702 is designed for measuring surface tensions and interfacial tensions
between two liquids with Du Noüy ring or Wilhelmy plate. The density of a liquid can also be
measured.
Inside this manual you will find information on how to use your Sigma tensiometer. You will also
find brief reviews of the concepts involved in your measurements and some practical advice on the
techniques involved. In order to obtain the maximum performance from your instrument you
should read this manual and keep it available for reference.

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2.Safety
WARNING!
The safety requirements listed in this manual must be followed in order to avoid
personal injury and damage to the instrument. If the equipment is used in a manner
not listed in this manual, protection provided by the equipment may be impaired.
WARNING!
RISK OF ELECTRICAL SHOCK. Do not connect this instrument to electrical power if
the enclosure is damaged or any of the covers or panels are removed. Make sure the
voltage rating on the instrument matches the line voltage available. Make sure the
power cord is not damaged and it is properly connected to the instrument and a
power outlet with protective earthing. Make sure that the power cord is easily
accessible after the equipment has been installed and set at its working position.
WARNING!
RISK OF ELECTRICAL SHOCK OR FIRE HAZARD. The instrument has been
designed for indoor use only. Do not expose it to rain, snow or dust. During storage
or transport the instrument should be kept dry. Temperatures below 0˚C and above
70˚C should be avoided. Do not operate at ambient temperatures below 15˚C and
above 30˚C.
When handling flammable liquids, use a minimum sample volume that is required for
successful measurement.
Ensure prevention of Electrostatic Discharge (ESD) when handling flammable liquids.
Contact your local authorities for information on ESD prevention practices.
Do not heat flammable sample liquids to temperatures higher than T–25 °C where T
is fire point of the sample liquid.
WARNING!
RISK OF INJURY. Do not configure the instrument with parts that are not supplied
by Biolin Scientific and not intended to be used with Attension instruments. Do not
install substitute parts that are not described in this manual. Do not perform any
modifications to the product.
If dangerous liquids are used, adequate protection such as proper ventilation, safety
glasses, etc., should be used: refer to the safety information from the supplier and
general safety regulations in your country. Carry out appropriate decontamination if
equipment is exposed to hazardous material.
WARNING!
RISK OF BURNS. Exercise caution when touching heated sample vessels (optional).
The vessel surface will reach dangerous temperatures when heated. The vessels are
marked with hot surface warning symbol.
Platinum Wilhelmy plate/rod is an excellent catalyst for oxidation of methanol vapor.
This reaction is very exothermic. In experiments in which the Wilhelmy plate/rod is
positioned above reagent-grade methanol this reaction may cause dangerous
heating of the plate/rod. Be aware of this phenomenon and take appropriate
precautions.

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CAUTION!
Make sure that the power is switched off when making any electrical connections
(apart from the USB cables). Connecting cables with power on may damage
instrument electronics. To disconnect the instrument, after turning the instrument
off, remove the power cord plug from the electric outlet.

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3.Physical Description
This section describes the physical construction of the Sigma 702 tensiometer. All necessary
hardware, software and accessories are included in the basic Sigma instrument making it possible
to take the instrument into use directly from its shipping crate.
CAUTION!: The transportation lock of the balance must be unlocked before using the instrument.
See section 3.1.2 for instructions.
3.1 Measurement Unit
The basic Measurement Unit consists of the following parts:
Main body containing electronics, power supply and user interface
Manually locked and calibrated super sensitive electro-magnetic balance
Lifting stage with long movement range for large samples
Membrane keyboard for manual system operations without PC control
Led lights for non-heating illumination of the measuring chamber
3.1.1 Main Body
The Main Body consists of the Power supply and the Main Electronic Board.
3.1.2 Balance
The balance for your Sigma 702 tensiometer is located in the upper housing of the Measuring Unit.
The balance is suitable for all kind of surface or interfacial tension measurements. One hook comes
down from the balance. This is used for hanging the probe used for the measurement. The travel
lock is located below the balance housing and looks like a small screw. Use this to lock the balance
when the Measuring Unit is moved (even from table to table). It is important to unlock the
transportation lock before using the instrument. To unlock, turn the screw so that it moves
outwards from the balance housing.
3.1.3 Lifting System
The stage of your Sigma tensiometer is lifted by a stepper motor. The speed range for the
movement of the sample stage is from 0.01 to 500 mm/min in increments of 0.01 mm/min. The
maximum range of movement is 100 mm. There are safety switches which stop the upward and
downward movement of your stage automatically at the highest and lowest positions of the stage.
3.1.4 Measuring stage
The measuring stage of your Sigma tensiometer has been designed so that it has a sufficient
separation between balance housing (top) and measuring stage for improved stability.
3.1.5 LCD Display
The built-in LCD display is used to monitor the status of the Sigma 702. It guides the user to the
next step in the measurement or calibration procedure and shows the results obtained.

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Figure 1: Startup screen
The bottom line of the display shows the balance reading, which is updated real-time. During
measurement, the bottom line shows the surface tension or interfacial tension value calculated
from the balance reading.
Figure 2: Adjusting measurement parameters
3.1.6 Manual Membrane Keyboard
The built-in Manual Membrane Keyboard allows the user to navigate through the menus of the user
interface and to control sample stage movement and the stirrer.
Figure 3: The manual membrane keyboard controls
To control the distance between the probe and the vessel, use the triangular buttons on the left
side of the keyboard. The upper triangle moves the stage up, the lower one moves it down. Press
and hold down a button to keep the stage moving. To save time, it is advisable to bring the liquid
surface close to the probe before starting measurement. The stage buttons are disabled during a
measurement.
The button with two arrows in circular shape in the lower middle part of the keyboard is the stirrer
button. Pressing it sets the stirrer on and off. The button is disabled during a measurement.

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The blue buttons OK, , and Stop/Cancel are used to navigate the menus on screen. Press
and to move the highlight on the desired operation and OK to select it. Stop/Cancel can be
used to return back to an upper menu level or to interrupt any operation.
3.2 Optional Accessories
Note: You need at least one of the probes described in sections 2.8.1 through 2.8.3 to perform
measurements with Sigma 702.
3.2.1 Du Noüy Ring
A platinum-iridium ring (Du Noüy ring) can be purchased separately for use in surface tension and
interfacial tension measurements. The ring should be cleaned regularly after use and treated
carefully to avoid deformation.
A good way to store the ring is to immerse it in ethanol by first hanging it on a hook attached to a
lid, which is then attached to a beaker filled half-full with ethanol. Then before using the ring again
flush it with pure ethanol and water, or burn it with a Bunsen burner (ca. 1000ºC flame) for a short
time (glowing yellow-red for a few seconds). In this way the ring will keep its form better and will
not deform as easily as by putting it back to the transport case after each measurement.
Figure 4: Du Noüy ring
3.2.2 Wilhelmy Plate
A thin platinum plate (Wilhelmy plate) can be purchased separately for surface tension
measurement. The measurement with Wilhelmy plate is based on measuring the increase in the
weight that the plate gets when it is wetted and water "hangs" from it (see figure 5). The force per
wetted length is proportional to the surface tension. In this case, wetted length is the perimeter of
the plate.
The Wilhelmy method is based on the assumption that the contact angle between the plate and the
liquid is zero.

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Figure 5. Water "hanging" from a Wilhelmy plate, increasing its weight.
A Wilhelmy plate can be cleaned by washing it with pure ethanol and de-ionized water. The plate
should also be burned glowing red with a Bunsen burner for a few seconds in order to burn all
remaining organic contaminants.
WARNING!
RISK OF BURNS. Platinum Wilhelmy plate/rod is an excellent catalyst for oxidation
of methanol vapor. This reaction is very exothermic. In experiments in which the
Wilhelmy plate/rod is positioned above reagent-grade methanol this reaction may
cause dangerous heating of the plate/rod. Be aware of this phenomenon and take
appropriate precautions.
3.2.3 Density Probe
A density probe (a glass ball with a wire hook attached to it) can be purchased separately for use
for density measurement with Sigma 702. The hook of the probe is mounted to the hook that
hangs from the balance housing.
The density measurement system of Sigma 702 must be calibrated for each density probe used.
3.2.4 Thermostatic Vessel
A thermostatic vessel is used for controlling the temperature of the sample liquid. It has two water
jackets that conduct water from an external bath/circulator heating or cooling. A glass vessel
should be used inside the thermostatic vessel. Sample vessels with a diameter of 70mm or less fit
in the thermostatic vessel. Note: The necessary external bath/circulator is not included.
Figure 6: Thermostatic vessel

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3.3 Cleaning procedure
In all measurements done with Sigma 702, the cleanliness of the used probes and beakers is
extremely important for reliable and reproducible results. The best cleaning procedure depends on
the samples used. Here is a typical cleaning procedure when water or oil is used.
Cleaning of the glass beaker
Rinse three times with n-heptane (only after preceding tests with oil), afterwards with 2-propanol
(also in case of unused beakers and after water testing). Rinse with hot tap water and afterwards
thoroughly with deionized water/bi-distilled water. Please see water requirements below.
Laboratory dish washer with integrated deionized water with the required quality may be used if
providing the required cleanliness. Be sure that all washing agents are removed completely before
drying.
Cleaning of the platinum probe
Rinse three times with n-heptane; afterwards with deionized water and heat it in the oxidizing
flame for approx. 5 s in an ethanol or natural gas burner to red heat.
Water used for the reference test
Bi-distilled or deionized water from a glass bottle with a surface tension of >70 mN/m at max.
25°C should be used. HPLC-grade water may be used if suitable.
Note: For pure water the following relationship between surface tension of water and temperature
exists:
σ= surface tension (mN/m)
T = temperature (K)
Cleaning the instrument
The exterior of the instrument can be cleaned with a damp cloth. Ensure that the surfaces are dried
immediately after cleaning. If liquid is accidentally spilled on the instrument, wipe the instrument
using a dry, clean cloth.
3.4 Maintenance
Only persons authorized by Biolin Scientific are allowed to perform maintenance and repairs on the
instrument. In case repair is needed, contact Biolin Scientific directly.
Cm
mN



15,0 

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4.Technical Specifications
Sigma 702
Electro-magnetic
balance
Maximum load
Weighing resolution*
Force resolution
ST Resolution with standard probe
Taring
Calibration
Locking
5 g
0.01 mg
0.01 mN
0.01 mN/m
Automatic
Manual
Manual
*Actual resolution of the balance.
Voltage and current
Input voltage
Frequency
Input current
Fuses
100 – 240 Vac
50 – 60 Hz
100 – 160 mA
T1.0A 5x20 mm
Environmental conditions
Ambient temperature
Ambient pressure
Ambient humidity
15 – 30 °C
700 to 1060 hPa
20 – 80% (non-
condensing)

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5.Measurement
5.1 Preparations for measurement
Before beginning a measurement, please go through the following checks and preparatory
operations:
Check that the transportation lock of the balance is fully open.
Turn Sigma 702 on at least half an hour before starting a measurement or calibration.
Calibrate the instrument if necessary (see section 5).
Check the condition of the measurement equipment you are going to use: A correct, non-
deformed shape is important for Du Noüy ring and Wilhelmy plate.
Figure 7: Cleaning a Du Noüy ring with a Bunsen burner.

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5.2 Measuring surface tension with a Du Noüy ring
1. Check the instructions in section 5.1 and make necessary preparations.
2. Mount the cleaned Du Noüy ring in the tensiometer hook.
3. If there is any doubt, check that the correct ring type is selected and also other measurement
settings are as preferred via Adjust parameters in the main menu. You can find the ring type
setting by selecting:
Adjust parameters -> Du Noüy ring parameters -> Ring type
using the arrow buttons ( and ) and OK button, and Stop/Cancel to return back to the main
menu. For information about choosing between Huh-Mason and Zuidema-Waters correction
methods, see section 4.2.1.
4. Pour the liquid to be measured in to the cleaned glass sample container. A liquid depth of at
least 11 mm is recommended.
5. Select Measure from the menu selection and press the OK button. In the following menu,
select Surface tension / ring and press the OK button.
6. You will now be asked, which density difference value to use. When measuring surface
tension, the density difference is
airliquid
 
.
7. You are asked to set the number of measurement points you want the device to make. One
point means a single measurement pull through the surface. If you specify a greater number of
measurement points, the instrument will perform the specified number of measurements and will
show the average value and standard deviation at the conclusion of the measurement. The values
of individual measurement samples can be seen by collecting data to PC by using a USB connection
and the PC software described in section 5.6 or by using an optional printer to collect the data.
However, the curve drawn on display during measurement helps you to detect any possible
anomalies among the sample measurement rounds.
8. Press OK to begin measurement and wait until it is finished. A curve is plotted during
measurement, showing the surface tension value calculated from the balance reading at each
instant. If your measurement consists of many measurement points, each of them gets a curve of
its own. However, the curves usually follow the same trajectory quite closely.
9. When finished, the measurement result is displayed on screen and the stage starts moving to
draw the probe out of the liquid. Please note that either Huh-Mason correction or Zuidema-Water
correction is applied, depending on your settings. You can also have the result displayed with both
corrections.
The result is calculated from the highest value of the measurement curve. In the case of several
measurement points, the result is calculated as the average of results from the individual
measurement points, and the sample standard deviation value is displayed.
10. After measurement, clean the Du Noüy ring and the glass sample container.

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5.2.1 Choosing a correction method: Huh-Mason or Zuidema-Waters
Briefly: When measuring surface tension or interfacial tension with Sigma 702 and a Du Noüy ring,
either of two possible methods can be used for correction factor calculation: Huh-Mason or
Zuidema-Waters. Generally, Huh-Mason is regarded as the more accurate one whereas Zuidema-
Waters is an older method and may be used, e.g., for compatibility with earlier results. Huh-Mason
is set as the default in Sigma 702.
Background: The starting point for calculating surface tension from balance reading is the
following formula:
ring
meniscus
basic r
F




4
,
where
basic

stands for the surface tension of the liquid being measured,
meniscus
F
is the maximum
lifting force that the meniscus hanging from the ring can withstand, and
ring
r
is the radius of the
Du Noüy ring. The term
r  4
amounts to the wetted length of the ring–the inner circumference
plus the outer circumference.
While giving results to the right direction, the basic formula does not correctly take into account
the effect of ring wire curvature on shape of the meniscus and thus the result. Therefore, a
correction factor is usually applied (automatically in Sigma 702 tensiometers). The most commonly
used methods for correction factor calculation are Huh-Mason and Zuidema-Waters, named after
their authors.
The precise correction factors for Huh-Mason correction are looked up and interpolated from a
numeric table that cannot be conveniently represented here.
The calculation formula for the Zuidema-Waters correction factor (
correction
F
), however, goes as
follows:
ring
wire
correction r
r
dDC
P
F679.1 04534.0
)(
452.1
7250.0 2


,
where
P
equals the force when the film ruptures in mN/m,
D
is the density of the heavy-phase at
25°C in g/ml,
d
is the density of the light-phase liquid (air if surface tension is measured) as g/ml,
C
is the circumference of the ring in mm,
ring
r
is the radius of the ring in mm,
wire
r
is the radius of
the wire of the ring.
When the basic result
basic

and the correction factor
correction
F
are known, the final result is their
product:
correctionbasiccorrected F

Sources:
C. Huh and S.G. Mason, Colloid & Polymer Sci. 253 (1975) 566-580.
H.H. Zuidema and G.W. Water, Industrial and Engineering Chemistry 13 (1941) 312-313

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5.3 Measuring interfacial tension with a Du Noüy ring
5.3.1 Push Mode and normal (pull) mode
An interfacial measurement is performed by pulling the Du Noüy ring from a polar liquid over the
interface to a non-polar liquid. Often, the polar liquid is heavier than the non-polar one, so the ring
is pulled upwards -- that is the normal mode. If, however, the non-polar liquid is heavier and falls
to the bottom of the sample vessel, the measurement must be performed in Push Mode, i.e. by
pushing the ring from the light-phase liquid downwards to the heavy-phase liquid.
When measuring in Push Mode, an extra weight must be attached to the Du Noüy ring in order to
prevent the ring from getting tilted or rising away from the hook as the interface exerts an upward
force towards the descending ring. The weight must be mounted on the ring before starting any
measurement in Push Mode.
5.3.2 Measurement steps
1. Check the instructions in section 5.1 and make necessary preparations.
2. Mount the cleaned Du Noüy ring in the tensiometer hook.
3. If there is any doubt, check that the correct ring type is selected and also other measurement
settings are as preferred via Adjust parameters in the main menu. You can find the ring
typesetting by selecting:
Adjust parameters -> Du Noüy ring parameters -> Ring type
using the arrow buttons ( and ) and OK button, and Stop/Cancel to
return back to the main menu. For information about choosing between Huh-Mason and Zuidema-
Waters correction methods, see section 5.2.1.
4. Pour the heavy-phase liquid into the glass sample container. A liquid depth of at least 14 mm is
recommended for normal pull-mode measurement. In push mode, the depth requirement varies
depending on the properties of the liquids measured but about 20 mm should be sufficient. See
section 4.3.1 for information about Push Mode and normal (pull) mode.
5. Select Measure from the menu selection and press the OK button. In the following menu, select
Interfacial tension / ring and press the OK button.
6. You will now be asked, which density difference value to use. When measuring interfacial
tension between two liquids phases, the difference is
phaselightphaseheavy  

. The density
difference may be input using the arrow and OK buttons on the keypad.
In the same screen you can toggle Push Mode. Please note that Push Mode must be set on or off
before making any selection that would move you to the next screen. See section 4.3.1 for
information about Push Mode.
7. You are asked to set the number of measurement points you want the device to make. One
point means a single measurement pull through the surface. If you specify a greater number of
measurement points, the instrument will perform the specified number of measurements and will
show the average value and standard deviation at the conclusion of the measurement. The values
of individual measurement samples can be seen by collecting data to PC by using a USB connection
and the PC software described in section 5.6 or by using an optional printer to collect the data.
However, the curve drawn on display during measurement helps you to detect any possible
anomalies among the sample measurement rounds.
8. When you press OK to continue, Sigma will instruct you to move the liquid sample close to the
probe or immerse the ring to liquid, depending on your selections.

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If you make a pull mode measurement, you will be asked to immerse the ring into the heavy-phase
liquid and then pour the light-phase liquid. That way you can perform the measurement without
first contaminating the ring in the light-phase liquid.
If Push Mode is used, an additional weight (called Push Mode weight) must be mounted on the ring
before starting a measurement.
9. Press OK to begin measurement and wait until it is finished. A curve is plotted during
measurement, showing the interfacial tension value calculated from the balance reading at each
instant. The highest value encountered will be displayed as the result of the measurement.
If you chose several measurement points, the result will be the average of the points, in which
case the standard deviation is also displayed.
10. When finished, the interfacial tension will be displayed on screen and the stage starts moving
to draw the probe out of the liquid.
11. Clean the Du Noüy ring and the glass sample container.
5.4 Surface tension measurement with a Wilhelmy Plate
5.4.1 Steps for measurement
1. Check the instructions in section 5.1 and make necessary preparations.
2. Mount the purified Wilhelmy plate in the tensiometer hook. See to it that no liquid drop hangs
from the bottom of the plate.
3. Check that the correct Wilhelmy measurement parameters are set. The settings can be found
by selecting Adjust parameters -> Wilhelmy settings.
- For taring mode, you can choose between Wet Taring and Dry Taring, of which Wet Taring
is the default. See section 5.4.2 for information about Wet Taring and Dry Taring.
- Stabilization time specifies how long to wait after the Wilhelmy plate is brought to the
correct depth before taking measurement. 4 seconds is the default, but with viscous liquids it may
take longer to reach a satisfactory state of equilibrium.
- Surface detection specifies the surface recognition threshold. The liquid surface is
recognized by seeing a sharp rise in force when the plate touches the liquid surface. Here the
needed force level can be specified. 2 mN/m in recommended to avoid false surface recognition
due to vibrations and air currents.
4. Pour the liquid to be measured into the glass sample container.
5. Select Measure from the menu selection and press the OK button. In the following menu,
select Surface tension / plate and press the OK button.
6. Set the number of measurement points you wish to make. If you choose more than one point,
the average of the measurement points and their standard deviation (STD) is displayed at the
conclusion of the measurement. The results of individual samples can be seen via the USB receiver

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software (see section 6.6) or by using an optional printer. The standard deviation reading on the
display after measurement will help you to detect any problems in the measurement sequence.
7. Sigma will instruct you to move the liquid sample close to the probe. This is particularly
important in Wilhelmy Plate measurement, since the plate approaches the surface rather slowly in
order the get an accurate reading of the surface position.
When the plate is close to the surface, press OK to begin the measurement. Wait until the
measurement has completed and write down the results (unless you use a PC data connection or
the optional printer to collect results automatically.)
8. Clean the Wilhelmy plate and the glass sample container.
5.4.2 Taring modes: Wet Taring and Dry Taring
With Wet Taring, the zero level for the balance is set equal to the balance reading of a wet plate
hanging on the balance hook. With Dry Taring, the zero level equals the balance reading of a dry
plate hanging from the balance hook.
Certain practical differences arise from the different objectives of Wet Taring and Dry Taring: As
the plate with Dry Taring should not touch water before taring, only one taring can be performed
for a multi-round measurement. With Wet Taring, however, taring is repeated before every
measurement round. Surface level is determined only once, regardless of the taring mode.
The measurement sequence with Wet Taring:
oAt first, the plate descends (i.e. stage ascends) slowly in order that the liquid surface
level may be accurately determined. Next, the plate is dipped into the depth of about 5
mm, and lifted up.
oFor each measurement round, the following is repeated: The plate waits in the air while
the balance is tared and then it is dipped to the depth of about 5 mm, after which it is
brought to the liquid surface level and waits a while as the weight on the balance hook
is measured read, and the plate is lifted up again.
The measurement sequence with Dry Taring:
oAt first the plate waits in the air, taring is performed. Then it descends slowly toward
the liquid surface, determining surface level.
oFor each measurement round: The plate is lifted up from the liquid surface, descends
to the depth of about 5 mm, moves to the surface level and determines the weight
(force) of the item hanging from the balance hook.
Wet taring is usually recommended, but Dry Taring allows the user to control the wetness of the
plate when taring if performed at beginning of measurement. The taring modes have no difference
in the interpretation of balance readings during taring and measurement phases.
If the user wishes to have a slightly wetted plate for taring, he/she may manually perform the
desired amount of wetting and then perform measurement with Dry Taring selected. In this case,
however, care should be taken that no drop of liquid is hanging from the plate, since that would
cause inaccuracy in the instruments' ability to detect the surface level.
5.5 Density measurement
NOTE! Density measurement is sensitive to vibrations. In order to ensure accurate measurements
the instrument should be placed on a vibration free table in an area where local air currents are at
a minimum
5.5.1 Density of a liquid
The density of a liquid can be measured using the glass ball probe supplied with the instrument.
The steps for performing the density measurement are as follows.

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1. Check the instructions in section 5.1 and make necessary preparations.
2. Place a sample container with sample liquid on the stage and carefully mount a clean and dry
density measurement probe on the balance hook.
3. Select Measure->Liquid Density from the main menu of Sigma 702 and follow the
instructions displayed.
4. Wait for the completion of the measurement and write down the density reading.
5. Clean the density probe and the glass sample container. Instructions for cleaning are given in
section 4.1.
5.5.2 Density of a solid object
The density of a solid object weighing no more than 4 or 5 grams can also be measured using the
Sigma 702 instrument. The accuracy of the measurement depends e.g. on the wettability of the
object and the shape of the object (glassy or porous).
In solid object measurement, calculations must be done manually. In these instructions, it is
assumed that you use a thin, lightweight wire to hang the solid object from the balance hook.
1. Check the instructions in section 5.1 and make necessary preparations.
2. Put a cup of pure water on the sample stage.
3. Check that the object whose density is to be measured is clean and dry.
4. Write down the balance reading before hanging the object on the balance hook. Call this
value
0
m
-- it should be close to 0. If the wire has any significant weight, measure
0
m
with
the wire hanging from the hook. This will compensate for the weight of the wire.
5. Carefully hang the object on the balance hook and check the balance reading. We call this
airin
m_
.
6. Drive the sample stage up, so that the object is immersed into water. When fully
immersed, write down the balance reading—this is called
waterin
m_
.
Now, the following 3 properties of the object can be calculated (continuing to next page):
- Mass:
0_ mmm airin 
- Volume:
waterwaterinairin mmV
 /)( __ 
, where
water

is the density of the water used in this
experiment.
- Density:
water
waterinairin
airin
mm
mm
V
m

__
0_



5.6 Collecting data to a PC
A USB cable can be used to connect your Sigma 702 and a PC for data collection using a program
called Attension Data Receiver. The program is included in the software USB drive that comes with
the instrument. Data collection is easy, since Sigma 702 sends the result of every measurement to
PC automatically. Attension Data Receiver can be installed by copying the program to a directory
and installing the necessary USB device driver.
The data receiver displays one line for each measurement result it receives, with fields for time
stamp, measurement result and the method used. With multi-sample measurements, a line is
output for every sample, while the field "Info type" specifies whether a particular line is about one
sample out of many or an ordinary measurement.

[ Attension®| KSV NIMA |QSense®] [20]
The lines displayed on screen can be copy-pasted to another program (such as spreadsheet) for
storage or analysis, and the output is also appended to a log file whose name can be set by the
user.
Figure 8: Attension Data Receiver to transfer measurement results to PC, including the
intermediate results of a multi-round measurement.
5.7 Using the optional printer
The optional printer can be used when you want to print your measurement results. Connect the
serial cable supplied with the printer between Sigma 702 back panel and the printer. Connect the
printer power cord to a mains outlet and power on the Sigma 702. The printer will automatically
print your measurement results after a measurement is completed.