KERN MLB50-3 Operating Instructions Manual

MLB50-3-BA-defsi-0310

28

GB

KERN MLB50-3

Version 1.0 05/2003

Operating Instructions
Moisture Analyzer

Table of contents:

1 Technical data ________________________________________________________ 30

2 Declaration of conformity _______________________________________________ 31

3 Fundamental information (general) _______________________________________ 32

3.1

Intended use ___________________________________________________________ 32

3.2

Inappropriate use_______________________________________________________ 32

3.3

Protective measures _____________________________________________________ 32

3.4

Warning ______________________________________________________________ 32

3.5

Guarantee _____________________________________________________________ 33

3.6

Monitoring the test substances ____________________________________________ 33

4 Fundamental safety information __________________________________________ 34

4.1

Observe the information in the operating instructions ________________________ 34

4.2

Staff training __________________________________________________________ 34

5 Transport and storage __________________________________________________ 34

5.1

Acceptance check _______________________________________________________ 34

5.2

Packaging _____________________________________________________________ 34

6 Unpacking, installation and commissioning_________________________________ 35

6.1

Place of installation, place of use __________________________________________ 35

6.1.1 Installation__________________________________________________________________ 35

6.1.2 List of items supplied _________________________________________________________ 35

6.2

Mains supply __________________________________________________________ 36

6.3

Connecting peripheral equipment _________________________________________ 36

6.4

Initial start-up _________________________________________________________ 36

6.5

Adjustment ____________________________________________________________ 37

6.6

Adjusting______________________________________________________________ 37

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7 Moisture determination _________________________________________________ 38

7.1

Use ___________________________________________________________________ 38

7.2

Sample material ________________________________________________________ 38

7.3

Sample preparation _____________________________________________________ 38

7.4

Drying temperature _____________________________________________________ 39

7.5

Application table (recommendations) ______________________________________ 40

7.6

Temperature calibration / adjustment______________________________________ 41

8 Setting the parameters __________________________________________________ 42

8.1

Temperature correction on “SubSt“ test object ______________________________ 43

8.1.1 Setting the correction factor ____________________________________________________ 44

8.2

Modes “modE“_________________________________________________________ 45

8.3

Maximum drying time “IntEr“ ___________________________________________ 46

8.4

Drying temperature “tEmP“______________________________________________ 46

8.5

Data query time interval “Strob“__________________________________________ 46

9 Operation ____________________________________________________________ 46

9.1

Control elements _______________________________________________________ 46

9.1.1 Overview of the keyboard______________________________________________________ 46

9.1.2 Overview of the display screen__________________________________________________ 47

9.2

Operation _____________________________________________________________ 47

9.2.1 Weighing___________________________________________________________________ 47

9.2.2 Taring ( key) ___________________________________________________________ 48

9.3

Determination of humidity _______________________________________________ 49

9.3.1 Test accuracy________________________________________________________________ 50

10 RS232 serial interface ________________________________________________ 51

10.1 Print format ___________________________________________________________ 51

10.2 Changing languages_____________________________________________________ 53

11 Maintenance, upkeep, disposal _________________________________________ 53

11.1 Cleaning ______________________________________________________________ 53

11.2 Maintenance, upkeep____________________________________________________ 53

11.3 Disposal _______________________________________________________________ 53

12 Troubleshooting _____________________________________________________ 54

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1 Technical data

KERN MLB 50-3
Maximum load rating (max.) 50 g
Minimum for drying 0.02 g
Temperature range 50°C-160°C
Setting the temperature in 1°C stages
Pre-heating stage (boost) No
Read off (d) 0.001g /0.01%
Repeatability in weighing
(=standard divergence)

0.001 g

Repeatability during drying
(=standard divergence)
Initial weight 1g
Initial weight 10g

0.2%

0.02%

Please note: recommended minimum weight 2g
Adjusting weight not added 50g (F2)
Ambient conditions 15°C ... 35°C ambient temperature

max. 80% air humidity; not condensing

Shutdown criterion Automatic:

End of drying if the results do not alter during 3
strobe intervals (=heating intervals).
If a time limit has been set drying will shut down
after this period expires.
Adjustable strobe interval: 1 s – 59 s

Manual:
According to set time (10 min to 590 min [=9h 50
min]) (without strobe interval)

Display after drying % humidity = weight reduction

(=residual weight/start weight)*100%

% dry matter = residual weight
(=weight loss/start weight)*100%

% ATRO
(=weight loss/residual weight)*100%

Details are not possible in grammes during drying.
Including sampling trays 10
Protective hood no
Type of projector 2 halogen quartz projectors

200 watts each

Display LED display/ character height 15 mm

3 displays for: - drying status

(depending on configuration)

- temperature

- drying time

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2 Declaration of conformity

KERN & Sohn GmbH

Ziegelei 1
D – 72336 Balingen
E-Mail: [e-mail]

Tel: 0049-[0]7433- 9933-0
Fax: 0049-[0]7433-9933-149
Internet: www.kern-sohn.com

Declaration of conformity

Declaration of conformity for apparatus with CE mark

Konformitätserklärung für Geräte mit CE- Zeichen

Déclaration de conformité pour appareils portant la marque CE

Declaración de conformidad para aparatos con disitintivo CE

Dichiarazione di conformitá per apparecchi contrassegnati con la marcatura CE

English

We hereby declare that the product to which this declaration refers conforms with the
following standards.

Deutsch

Wir erklären hiermit, dass das Produkt, auf das sich diese Erklärung bezieht, mit den
nachstehenden Normen übereinstimmt.

Français

Nous déclarons avec cela responsabilité que le produit, auquel se rapporte la présente
déclaration, est conforme aux normes citées ci-après.

Español

Manifestamos en la presente que el producto al que se refiere esta declaración est´´a de
acuerdo con las normas siguientes

Italiano

Dichiariamo con ciò che il prodotto al quale la presente dichiarazione si riferisce è con­forme alle norme di seguito citate.

Moisture Balance: KERN MLB 50-3

Mark applied EU Directive Standards

73/23EEC Low voltage EN 60950

89/336EEC EMC EN 50081-1

EN 50082-1

Date: 01.05.2003 Signature:

Gottl. KERN & Sohn GmbH
Management

Gottl. KERN & Sohn GmbH, Ziegelei 1, D-72336 Balingen, Tel. +49-[0]7433/9933-0,Fax +49-[0]7433/9933-149

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3 Fundamental information (general)

3.1 Intended use

The balance you have acquired serves to determine the weighing value of the mate­rial to be weighed. It is intended to be used as a “non-automatic“ balance, i.e. the
material to be weighed is manually and carefully placed in the centre of the weighing
plate. The weighing value can be read off after a stable weighing value has been ob­tained.

3.2 Inappropriate use

Do not use the balance for dynamic weighing. In the event that small quantities are
removed or added to the material to be weighed, incorrect weighing results can be
displayed due to the “stability compensation“ in the balance. (Example: Slowly drain­ing fluids from a container on the balance.)
Do not leave a permanent load on the weighing plate. This can damage the measur­ing equipment.
Be sure to avoid impact shock and overloading the balance in excess of the pre­scribed maximum load rating (max.), minus any possible tare weight that is already
present. This could cause damage to the balance.
Never operate the balance in hazardous locations. The series design is not explo­sion-proof.
Structural alterations may not be made to the balance. This can lead to incorrect
weighing results, faults concerning safety regulations as well as to destruction of the
balance.
The balance may only be used in compliance with the described guidelines. Varying
areas of application/planned use must be approved by KERN in writing.

3.3 Protective measures

The moisture analyser of Safety Class 1 may only be connected through a carefully
installed socket with protective earth (PE). The protective effect must not be can­celled out by the use of an extension lead without earth wire. For power supplies from
mains not provided with a protective earth, an equivalent protection meeting the valid
installation regulations must be provided by a qualified electrician.

3.4 Warning

Individual parts of the housing (e.g. ventilation grille ...) can become very hot during
operation. Avoid touching the apparatus except by the handles provided for this pur­pose.
Sample materials which produce corrosive vapours (e.g. acids) can cause problems
of corrosion of components. The MLB50-3 should be used primarily for drying hy­drous substances.
The MLB50-3 must not be used to analyse highly inflammable samples which pre­sent an explosion hazard.

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3.5 Guarantee

The guarantee is not valid following

- non-observation of our guidelines in the operating instructions

- use outside the described applications

- alteration to or opening of the device

- mechanical damage and damage caused by media, liquids

- natural wear and tear

- inappropriate erection or electric installation

- overloading of the measuring equipment

3.6 Monitoring the test substances

The metrology features of the balance and any possible available adjusting weight
must be checked at regular intervals within the scope of quality assurance. For this
purpose, the answerable user must define a suitable interval as well as the nature
and scope of this check. Information is available on KERN’s home page (www.kern-

sohn.com) with regard to the monitoring of balance test substances and the test

weights required for this. Test weights and balances can be adjusted quickly and at
a reasonable price in KERN’s accredited DKD calibration laboratory (return to na­tional normal).

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4 Fundamental safety information

4.1 Observe the information in the operating instructions

Please read the operating instructions carefully before erecting and commissioning,
even if you already have experience with KERN balances.

4.2 Staff training

The device may only be operated and looked after by trained members of staff.

5 Transport and storage

5.1 Acceptance check

Please check the packaging immediately upon delivery and the device during un­packing for any visible signs of external damage.

5.2 Packaging

Please retain all parts of the original packaging in case it should be necessary to re­turn items at any time.
Only the original packaging should be used for return consignments.
Before despatch, disconnect all attached cables and loose/movable parts.
Apply any intended transport security devices. Secure all parts, e.g. glass windshield,
weighing plate, power unit etc., to prevent slipping and damage.

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6 Unpacking, installation and commissioning

6.1 Place of installation, place of use

The balance is constructed in such a way that reliable weighing results can be
achieved under normal application conditions.
By selecting the correct location for your balance, you will be able to work quickly and
precisely.

Therefore please observe the following at the place of installation:

-

Place the balance on a firm, level surface;

-

Avoid extreme heat as well as temperature fluctuation caused by installing
next to a radiator or in the direct sunlight;

-

Protect the balance against direct draughts due to open windows and doors;

-

Avoid jarring during weighing;

-

Protect the balance against high humidity, vapours and dust;

-

Do not expose the device to extreme dampness for longer periods of time.
Inadmissible bedewing (condensation of air moisture on the device) can occur
if a cold device is taken into a significantly warmer environment. In this case,
please acclimatise the device for approx. 2 hours at room temperature after it
has been disconnected from the mains.

-

Avoid static charging of the material to be weighed, weighing container and
windshield.

Major display deviations (incorrect weighing results) are possible if electromagnetic
fields occur as well as due to static charging and instable power supply. It is then ne­cessary to change the location.

6.1.1 Installation

Use the foot screws to level the balance until the air bubble in the bubble level is in
the prescribed circle.

6.1.2 List of items supplied
Standard accessories: Available optional accessories:

- Balance including humidity - Aluminium trays (item no.:MLB-A01)
identifier attachment - Glass fibre filter (item no.:RH-A02)

- Tray holder - Temperature calibration set

- 10 sampling trays - (item no.:MLB-A03)

- Mains cable

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6.2 Mains supply

A mains cable is used for the electric power supply.
Please check whether the balance voltage intake has been set correctly. The balance
may only be connected to the mains supply if the details on the balance (label) and
the customary on-site mains voltage are identical.

Important:

Does the designation (220 V 50 Hz) comply with the customary on-site mains voltage?

-

Do not connect if there are differences in the mains voltage!

-

The balance may be connected if in compliance.

6.3 Connecting peripheral equipment

The balance must be disconnected from the mains before connecting or disconnect­ing additional equipment (printer, PC) to or from the data interface.

Only use KERN accessories and peripheral equipment with your balance. These
have been ideally coordinated to your balance.

6.4 Initial start-up

The accuracy of the balance depends on the local acceleration of the fall.
Please be sure to observe the information in the chapter on “adjusting”.

Use the main switch (above the power plug) to switch on the balance. ”tEmP “
will appear.

You have two choices:

1. Press the key, the balance will run through a ”tEst “ mode. “0.000 “ will appear
on the display screen after a few seconds. A short warm-up period of approx. 10
minutes is advisable for stabilisation purposes.

2. It is possible to start up a pre-heating process that pre-heats the weighing region
to a reasonable drying process temperature. This pre-heating process is only practi­cal before initial drying if there are to be several consecutive drying procedures.
This procedure can be triggered whilst “tEmP “ is on the display screen by operating

the key. The balance switches automatically to weighing mode after a few
minutes.

Use the key to enter weighing mode.

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6.5 Adjustment

As the acceleration value due to gravity is not the same at every location on earth,
each balance must be coordinated – in compliance with the underlying physical
weighing principle - to the existing acceleration due to gravity at its place of location (
only if the balance has not already been adjusted to the location in the factory). This
adjustment process must be carried out during the initial start-up, after change in lo­cation and variation of surrounding temperature. It is also recommendable to adjust
the balance periodically during weighing operation in order to obtain exact measured
values.

6.6 Adjusting

Using a precision weight, the accuracy of the balance can be checked at any time
and adjusted.

Method of approach when adjusting:

Ensure sound ambient conditions.
Use the main switch (above the power plug) to switch on the balance. ”tEmP “ will

appear on the display screen. Press the key, the balance will run through a ”tEst
“ mode. “0.000 “ will appear on the display screen after a few seconds. A short warm­up period of approx. 10 minutes is advisable for stabilisation purposes.

Start up the adjusting process by operating the key. “------------- “ will appear on
the display screen for a few seconds.

The key must be pressed whilst “-------------“ is on the display screen.
Subsequently, “noCAL“ will appear on the display screen . “-LoAd-“ will appear on

the display screen after a few seconds, followed by the nominal value of the adjusting
weight.

The calibration process can be aborted during this period by pressing the key.
Now apply the adjusting weight and calibration will take place (please wait).
“ CAL “ will appear on the display screen, followed by ” rELoAd “ a few seconds

later.
Now remove the adjusting weight from the weighing plate.
The adjusting process is completed. The adjusting weight can be re-applied in order

to check the calibration. If the displayed value is not correct, adjusting should be re­peated.

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7 Moisture determination

7.1 Use

The rapid determination of moisture content is of enormous significance wherever
moisture has to be added to or removed from a product during manufacture. For in­numerable products, the moisture content is both a measure of quality and also an
important cost factor. When trading in industrial or agricultural products, as well as in
products in the chemical or foodstuffs field, firm limits for moisture content, defined by
sales agreements and standards, often apply.

7.2 Sample material

Samples with the following properties can usually be determined satisfactorily:

♦ Granular or powdery, floatable solids.
♦ thermally stable materials, which readily give off the moisture to be determined

without volatilising other constituents.

♦ Liquids, which evaporate to dryness without forming a skin.

The determination can be difficult in samples which:

♦ are viscous/sticky liquids.
♦ tend to form a crust or skin readily on drying.
♦ tend to decompose easily or liberate different constituents on heating.

7.3 Sample preparation

Special preparation of the samples is, in many cases, not required. Large solid bod­ies, e.g. kernels and grains, should, however, be ground. Both the drying time and
the accuracy which can be achieved will be greatly influenced by the sample distribu­tion. The result is that there are two contradictory requirements:
The lighter the load being weighed, the shorter the drying times which can be
achieved and the heavier the load, the more accurate will be the result.

Sample distribution:

Solid material

Distribute powdered and granular samples evenly over
the balance pan. Reduce the size of coarse samples
(grind, mortar)

Liquids

Apply tough and sticky products thinly. the use of circular
glass-fibre filters or quartz-sand is recommended.

Weight loss through spattering can be prevented by
covering the sample with a circular glass fibre filter. If
circular glass-fibre filters or quartz-sand are used the
weight must be subtract by tarring.

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7.4 Drying temperature

Consideration should be given to the following influencing factors when setting the
drying temperature:

Sample surface:
Contrary to powdery and granular samples, fluid and spreadable samples have a
smaller surface that tends to transfuse heat energy.
The use of a glass fibre filter improves heat insertion.

Colour of the sample:
Pale samples reflect more heat radiation than dark samples and therefore require a
higher drying temperature.

Availability of volatile matter:
The better and faster water or other volatile matter is available, the lower the setting
for the drying temperature. If the availability of water is poor (e.g. in plastics), the
water must be calcinated at a high temperature (the higher the temperature, the
higher the water vapour pressure).
Similar results can be achieved using other humidity identification methods (e.g.
cabinet dryer) by experimental optimisation of the setting parameters such as tem­perature, heating grade and shut-down criteria.

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7.5 Application table (recommendations)

Preparation of the standard sample:

-

Distribute the sample evenly on the aluminium tray.

-

Reduce the sample to small pieces and distribute evenly on the aluminium
tray.

Preparation of special samples:

-

A glass fibre filter can be used if the test material is sensitive or difficult to dis­tribute (e.g. mercury).

-

Apply the sample evenly to the glass fibre filter and cover with a second glass
fibre filter.

-

The glass fibre filter can also be used for protection against material splashes
(every splash adulterates the final result).

MATERIAL Weight of

test item

(g)

Drying tem-

perature

(º C)

Date

query

interval

(s)

% humidity or

% solid body

Standard

divergence

Drying

time

(min)

Dry piece of
apple

5-8 100 10 76.5 0.1 10-15

Moist apple 5-8 100 10 7.5 5-10
Butter 2-5 138 15 16.3 0.1 4.5
Mustard 2-3 130 20 76.4 0.7 10
Ground cof­fee

2-3 106 5 2.8 0.1 4

Cornflakes 2-4 120 15 9.7 5-7
Yogurt 2-3 110 15 86.5 4.5-6.5
Powdered
coffee cream

2-3 130 15 78.5 0.1 6-8

Cocoa pow­der

2-3 106 20 0.1 0.1 2

Crisps 3-4 106 15 6.9 0.1 7.5
Margarine 3-4 138 20 16 0.1 10
Mayonnaise 1-2 138 20 56.5 0.4 10
Powdered
milk

2-4 90 15 5 0.2 6

Milk choco­late

2-5 106 15 1.3 0.1 3.5

Red wine 3-5 100 15 97.4 0.1 15-20
Chocolate
powder

2-4 100 5 1.9 0.1 4

Sunflower oil 10-14 138 20 0.1 2
Instant soup
powder

2-3 80 15 3 0.2 4.5-7

Sugar 4-5 138 15 11.9 0.1 10
Milk 2-3 120 15 88 0.2 6-8
Flour 8-10 130 10 12.5 0.1 4-5
Cement 8-12 138 15 0.8 0.1 4-5
Paper 2-4 106 20 6.4 0.1 10
Sludge 11-12 130 15 80 90
Polyamide 2-5 138 20 2 0.2 75
Dust 5-10 104 10 7.3 0.3 8-15
Charcoal 8-10 120 10 3.8 0.1 8-10

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7.6 Temperature calibration / adjustment

The temperature can be checked and re-adjusted if necessary using the optional
temperature calibration set (MLB-A03).

Temperature calibration

-

The balance is in normal weighing mode.

-

Insert the temperature sensor through the balance cover opening and push in
close to the weighing plate (see pictures).

Guide bush for temperature sensor

-

-

-

Press the key and then press the and keys simultaneously.
A “Code“ is now queried on the display screen.

-

Use the arrow keys to enter the correct code (“002003“).

Numerical entry from 0-9

For changing the entry point on the display screen

-

Press the key. “St_tE “ will appear on the display screen - the temperature
sensor setting programme.

-

Press the key. The temperature inside the weighing region will now appear.
If this is not 20°C, please use the arrow keys to alter the temperature.

-

Press the key. If a temperature of 20°C is entered, a number of approxi­mately 4000 will appear on the display screen.

-

The key is now used to start temperature calibration. The balance will now
heat up to 50% of its total power.

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-

The balance should not be moved during this procedure in order to achieve a sta­ble result. The balance will have achieved a stable temperature value after
approx. 15 minutes.

-

The temperature in the weighing region should now have reached approx. 80°C.

-

Press the key. “opEn“ will appear on the display screen.

-

The cover can now be opened. + 2°C is now added on to the actual temperature,
e.g. if the thermometer is at 79°C, 79°C + 2°C = 81°C is entered.

2°C must be added to every temperature value.

-

The thermometer can now be removed from the weighing region.

-

The procedure is completed.

8 Setting the parameters

The following keys are used to set and select the parameters:

Function key – selects the parameters and adopts settings

Used to run through the various parameter settings, numerical entry
from 0-9

Used to change the entry point on the display screen

Parameter selection:

-

The balance is in weighing mode. Press the key and ”SubSt“ will ap­pear on the display screen.

(Details chapter: Temperature correction on ”SubSt “ test object)

-

Press the key again and ”modE“ will appear on the display screen.

(Details chapter: Mode “modE “).

-

Press the key again and ” intEr “ will appear on the display screen.
(Details chapter: Maximum drying time “IntEr “). Please note: This menu item
only appears in modes 4 - 7.

-

Press the key again and ”tEmP“ will appear on the display screen.

(Details chapter: Drying temperature “ tEmP “)

-

Press the key again and “Strob “ will appear on the display screen.

(Details chapter: Data query interval)

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8.1 Temperature correction on “SubSt“ test object

Certain materials give off more heat than is imported from outside.
Correction is necessary in this case in order to achieve an accurate measurement
result.
This setting allows the user to correct differences between the set humidity identifier
temperature and the actual temperature measured on the test item.
The balance is able to store 9 different correction factors.
These can be determined, set and selected as follows:
In order to set the appropriate correction factor it is necessary to carry out a drying
procedure and to measure the temperature in the interior of the test item.

Procedure:

The balance is in normal weighing mode. Apply a test quantity to the weighing plate.
Insert a thermo sensor into the test item.
The set drying parameters are:

-

SubSt = 0

-

modE = 7

-

IntEr = 30:00 minutes or longer

-

tEmP = a typical value for the sample

-

Strob = 20 seconds

Press the key in order to display the parameters. Press the key again to
start the test. Calculation of the correction factor can be carried out if the temperature
in the test item proves to be stable after a certain period of time.

Formula: T (measured) – T (set)
Correction = ---------------------------------------------­ T (set)

Example: The measured temperature amounts to 121°C, the temperature is set at
110°C, the correction is 0.10.

Typical materials with high temperature radiation:

Material Set temperature Measured

temperature

Correction factor

Flour

100°C 103.7°C 0.04

Coal dust

100°C 122°C 0.22

Damp tea leaves

100°C 120.5°C 0.20

Dry tea leaves

100°C 108.5°C 0.08

Cement

100°C 121°C 0.21

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8.1.1 Setting the correction factor

The balance is in weighing mode. Press the key and ” Subst “ will appear on
the display screen.

Use the key to select the correction factors (1-9).

Use the key to confirm selection. “ SubCoF “ will now appear on the display
screen and the temperature display flashes.

Now use the and keys to enter the determined correction factor. Use the

key to accept entry.

If the entered correction factor is > 0.99, “FALSE “ will appear on the display screen
and the entry will not be adopted. Repeat the entry using a new factor (<1) .

If you now activate the stored correction factor during testing, this will be allowed for.

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8.2 Modes “modE“

The following keys are used to set and select the parameters:

Function key – selects the parameters and adopts settings

Used to run through the various parameter settings, numerical entry
from 0-9

Used to change the entry point on the display screen

7 different modes are available.

Mode 1:

Percentage humidity (%)
Weight loss as against initial value
Drying is concluded if the weighing result of three consecutive heating intervals re­mains unchanged.

Mode 2:

Percentage weight value (%) as against initial value
Drying is concluded if the weighing result of three consecutive heating intervals re­mains unchanged.

Mode 3:

Percentage humidity as against solid body
Drying is concluded if the weighing result of three consecutive heating intervals re­mains unchanged.

Mode 4:

Percentage humidity (%)
Weight loss as against initial value
Drying is concluded if the weighing result of three consecutive heating intervals re­mains unchanged or if the time deadline has expired.

Mode 5:

Percentage weight value (%) as against initial value
Drying is concluded if the weighing result of three consecutive heating intervals re­mains unchanged or if the time deadline has expired.

Mode 6:

Percentage humidity as against solid body
Drying is concluded if the weighing result of three consecutive heating intervals re­mains unchanged or if the time deadline has expired.

Mode 7:

Percentage humidity (%)
Weight loss as against initial value
Drying is concluded if the time limit has expired.

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8.3 Maximum drying time “IntEr“

Drying modes 4 – 7 allow predefinition of the maximum drying period. This can be
predefined between 10 minutes and 9 hours 50 minutes.

8.4 Drying temperature “tEmP“

The drying temperature can be selected between 50°C and 160°C.

8.5 Data query time interval “Strob“

The “Strob“ interval time is the time between two points in time of the query result
data transfer via the RS-232 interface.
When using modes 1 – 6 the test is concluded if 3 query results are the same. This is
the case if no further moisture is able to escape from the sample.

Note:

The following keys are used to set and select the parameters (chapter 8.3 – 8.5):

Function key – selects the parameters and adopts settings

Used to run through the various parameter settings, numerical entry
from 0-9

Used to change the entry point on the display screen

9 Operation

9.1 Control elements

9.1.1 Overview of the keyboard

Function key – selects the parameters and adopts settings

Used to run through the various parameter settings, numerical entry
from 0-9

Used to change the entry point on the display screen

Transmits the test or weighing results to a printer via the RS-232 inter­face.

Starts the drying procedure.

Sets the display to zero in weighing mode. The drying process can be
aborted by pressing the stop key.

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9.1.2 Overview of the display screen

9.2 Operation

9.2.1 Weighing

Use the main switch (above the power plug) to switch on the balance. A short warm­up period of approx. 10 minutes is advisable for stabilisation purposes.

Press the key and wait for the “0“ indication. Now it is ready for use.

Important: If the display does not show “0“ press the key.

Only now (!) place object on the weighing pan. Make sure that the weighing object
does not stripe or touch the housing or base. Now the weight will be indicated.
If the object should be heavier than the weighing range allowance, “FULL“ (over-
load) will appear on the display.

Indicator for:

- Set time

- Test time

Indicator for:

- Temperature selection

- Process temperature

- Entry of correction factor

Indicator for :

- Drying mode selection
(“modE“)

- Correction factor selection
(“subCoF“)

Main display panel:

- Function display

- Error messages

- Play back result

- Adjusting functions etc.

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9.2.2 Taring ( key)

Use the main switch (above the power plug) to switch on the balance. A short warm­up period of approx. 10 minutes is advisable for stabilisation purposes.

Press the key and wait for the “0“ indication.

Place the jiffy on the weighing pan and press the key. Display again shows “0“.
Now the weight of the jiffy is memorised internally.

By pressing the key after a weighing procedure, “0“ will appear on the display
again.

The taring procedure can be repeated continuously, for instance when mixing several
components. The limit is reached when the full weighing range is overlaid.
After having removed the jiffy the total weight will appear flashing as a minus indica­tion.

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9.3 Determination of humidity

Use the main switch (above the power plug) to switch on the balance. ”tEmP“ will
appear on the display screen.

You have two choices:

1. Press the key, the balance will run through a ”tEst “ mode. “0.000 “ will appear
on the display screen after a few seconds. A short warm-up period of approx. 10
minutes is advisable for stabilisation purposes.

2. It is possible to start up a pre-heating process that pre-heats the weighing region
to a reasonable drying process temperature. This pre-heating process is only practi­cal before initial drying if there are to be several consecutive drying procedures.
This procedure can be triggered whilst “tEmP “ is on the display screen by operating

the key. The balance switches automatically to weighing mode after a few min­utes.

Use the key to enter weighing mode.

Apply an empty sampling tray. Press the key, place the sample quantity on the
tray (see diagram 1) and close the cover.

Sample distribution:

Solids

Distribute powdery and granular samples evenly on the
sampling tray.
Reduce coarse grained samples to small pieces (grind,
mortar)

Fluids

Apply viscous and gluey samples in thin layers. It is ad­visable to use a glass fibre filter.

Avoid weight loss due to splashes by covering the sample
with a glass fibre filter. Remember to tare off the weight of
the glass fibre filter.

Diagram 1

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There should be ample distance between the sample material and the cover when
closing the cover. (Diagram 2).

Note:

Double-check that only the sample material is displayed as a load. The sampling tray
must be tared.

Press the key to start up the humidity determination process.
The set parameters can be seen on the display screen.

The drying process is started by pressing the key again. This process can be

aborted at any time by pressing the key.

The drying process duration depends on the set mode.

Mode 1-3 checks any alteration in the weighing result (details ”mode“ chapter)
Mode 4-7 is time-dependent (details function type “mode“ chapter)

9.3.1 Test accuracy

The size of the sample has a great influence on the accuracy of the test procedure.
A larger sample provides a more exact test result. However, the drying procedure
duration increases with the size of the sample.
The test result can be adulterated to a great degree if the test samples are too small
(light). If samples are used that dry out very quickly, it should be ensured that the
drying parameters (temperature, time interval) are set in an appropriate fashion.

It is very important to apply the test material evenly to the sampling tray (see diagram
1 chapter 9.3).

If you wish to ensure that the time interval between two data transfers has been se­lected correctly, it is necessary to carry out an additional test using longer time inter­vals. In the event that a significant divergence is determined when comparing both
humidity values, the time interval should be extended.

Diagram 2

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10 RS232 serial interface

The balance can be operated with a printer that is connected to the RS-232 inter­face. The final results can be printed off in English or German. Language selection is
described in chapter 10.2.

Type of data transfer

The baud rate and parity of the balance must be concordant with those of the periph­eral device in order to guarantee data transfer from the balance to the peripheral de­vice by means of the RS232 interface.

The balance interface parameters are:
4800 baud
8 data bit
no parity
1 stop bit
no handshaking

Pin assignment of the balance output plug socket (front view)

5 1

9 6

Pin 3: Receive data
Pin 5: Signal ground
no handshaking

10.1 Print format

The print format (print-out) is also in “g” when in weighing format.
When in drying format the value displayed on the display screen is transmitted via the
interface as “%“. The print-out is also in “%” format.

A) Display format in weighing mode
A value can be transmitted via the RS-232 interface during weighing procedure by

pressing the key.

The format of this signal is:

+xxx.xxx g<CR><LF>

xxx.xxx The current weight is displayed.

B) Display format in test mode

The results are transmitted via the RS-232 interface according to the set time inter­vals during the test procedure (chapter 8.5 time interval of the ”Strob“ data query).
The format of this signal is:

xxx.xx %<CR><LF> xxx.xx The current result is displayed.

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Example:

C) Final result print-out

This function is used to print out the completed test procedure result including all im-

portant metered values and is triggered by operating the key.

This print-out is similar to the following:

MODE 1.
WEIGHT REDUCTION 31.65 %
START WEIGHT 33.44 g
RESIDUAL WEIGHT 10.52 g
FINAL TEMPERATURE 106 º C .
DRYING TIME 0:04:20.
Time interval 20 s.

The result is shown on the display screen once the test procedure has been com­pleted.

This value can be printed off by using the key. Print-out is not possible once the
value has been deleted from the display screen.

0.00 %

2.03 %

5.00 %

7.39 %

10.82 %

15.43 %

21.17 %

26.21 %

29.91 %

30.86 %

30.86 %

31.65 %

31.65 %

31.65 %

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10.2 Changing languages

Use the main switch to switch the balance on.
The balance starts up using the language last selected.
To change languages switch the balance off and on again.
The balance displays the “PAs ??“ software version, followed by “tEst“ for a few

seconds. Press the key whilst “tEst“ is being displayed.
Either “Lan En“ for English or “Lan dE“ for German will appear on the display
screen to set the balance.

Use the key to change between the languages.

Use the key to accept the setting.

“EntEr“ will now appear on the display screen. Use the key to confirm the set-
ting. The balance will run through a ”tEst” mode. “0.000“ will appear on the display
screen after a few seconds.

11 Maintenance, upkeep, disposal

11.1 Cleaning

Please disconnect the device from the operating voltage before cleaning.

Only use a cloth dampened with mild suds and not aggressive cleaning agents (sol­vents or similar). Please ensure that fluids are not able to get into the device and rub
off using a clean, soft cloth.
Loose sample residue/powder can be removed carefully using a brush or hand vac­uum cleaner.

Remove any spilt material to be weighed immediately.

11.2 Maintenance, upkeep

The device may only be opened by trained service engineers authorised by KERN.
Disconnect from the mains supply before opening.

11.3 Disposal

The operating company shall dispose of the packaging and the device in compliance
with the valid national or regional law of the operating location.

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12 Troubleshooting

The balance should be switched off for a short time following an interruption in the
programme sequence and disconnected from the mains supply. It is then necessary
to repeat the weighing process from the beginning.

Help:

Interruption Possible cause

Weight display is not illuminated.

• The balance is not switched on.

• The mains supply connection has been

interrupted (mains cable not plugged
in/faulty).

• Power supply interrupted. .

The weight display changes continu­ally

• Draught/air movement

• Table/floor vibrations

• The weighing plate is in contact with for-

eign matter.

• Electromagnetic fields / static charging

(choose different location/switch off inter­fering device if possible)

The weighing result is obviously in­correct

• The balance display is not set to zero

• Adjustment is no longer correct.

• Great fluctuations in temperature.

• Electromagnetic fields / static charging

(choose different location/switch off inter­fering device if possible)

Switch the balance off if other error messages should appear and then switch on a­gain. Contact the manufacturer if the error message does not disappear.