KERN PBJ-N User manual
KERN & Sohn GmbH
Ziegelei 1
D-72336 Balingen
Tel: +49-[0]7433- 9933-0
Fax: +49-[0]7433-9933-149
Internet: www.kern-sohn.com
Service Manual
Precision balances
KERN PBJ-N
Version 1.0
02/2018
GB
PBJ_N-SH-e-1810
PBJ_N-SH-e-1810.docx 2
GB
KERN PBJ-N
Precision balances
Version 1.0 03/2018
Service manual
Content
1Basic Information ................................................................................................5
2Introdution............................................................................................................5
3Appliance overview .............................................................................................6
3.1 Keyboard overview..................................................................................................................... 7
3.2 In menu:....................................................................................................................................... 8
3.3 Numeric entry.............................................................................................................................. 8
3.4 Setting the decimal point when entering numerical values................................................... 9
3.5 Overview of display.................................................................................................................. 10
4Basic Information (General)..............................................................................11
4.1 Proper use................................................................................................................................. 11
4.2 Improper Use............................................................................................................................. 11
4.3 Warranty .................................................................................................................................... 11
4.4 Monitoring of Test Resources................................................................................................. 12
5Basic Safety Precautions..................................................................................12
5.1 Pay attention to the instructions in the Operation Manual ..................................................12
5.2 Personnel training ....................................................................................................................12
6Transport and storage.......................................................................................12
6.1 Testing upon acceptance......................................................................................................... 12
6.2 Packaging..................................................................................................................................12
7Unpacking, Setup and Commissioning ...........................................................13
7.1 Installation Site, Location of Use............................................................................................ 13
7.2 Unpacking / Scope of delivery ................................................................................................13
7.3 Placing....................................................................................................................................... 15
7.4 Mains connection .....................................................................................................................18
7.5 Switch power supply on........................................................................................................... 18
7.6 Connection of peripheral devices........................................................................................... 19
7.7 Initial Commissioning .............................................................................................................. 19
8Adjustment.........................................................................................................20
8.1 Manual adjustment by CAL button ......................................................................................... 20
8.2 Adjustment with internal weight .............................................................................................20
9Adjustment test..................................................................................................21
9.1 Adjustment test with external weight..................................................................................... 22
9.2 Adjustment test with internal weight......................................................................................23
9.3 Automatic adjustment by PSC (Perfect Self Calibration), only models PBJ...................... 24
9.4 Automatic adjustment by Clock-CAL..................................................................................... 24
10 Verification......................................................................................................26
11 The menu ........................................................................................................27
11.1 Navigation in the menu............................................................................................................ 27
12 Service, maintenance, disposal ....................................................................30
12.1 Clean.......................................................................................................................................... 30
12.2 Service, maintenance............................................................................................................... 30
12.3 Disposal..................................................................................................................................... 30
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13 Instant help .....................................................................................................31
13.1 Error message: .........................................................................................................................32
14 Operating method for the adjustment service.............................................34
14.1 Gaining entry to the service menu.......................................................................................... 34
14.2 Service menu contents ............................................................................................................35
15 Balance assembly / dismantling precautions..............................................36
15.1 Dismantling / Assembly........................................................................................................... 36
15.2 Transporting Balance............................................................................................................... 36
15.3 DISMANTLING........................................................................................................................... 37
16 ASSEMBLY .....................................................................................................38
16.1 Replacement of Components..................................................................................................39
16.1.1 Replacing the Assy,Display (B4)......................................................................39
16.2 Replacing the Assy,Analog (B3) .............................................................................................39
16.3 DETACH THE ASSY,DISPLAY (B4) AND PLACE IT TO THE RIGHT OF THE BALANCE IN A
LOCATION FREE OF DIRT AND STATIC............................................................................................ 39
16.4 Replacing the Assy,I/F (B5) .....................................................................................................41
16.5 Replacing the Switch board assy (C3) ................................................................................... 41
16.6 Replacing the Assy,Detector (U8)........................................................................................... 42
16.7 Replacing the Weight loader assy (10) (UW series only) .....................................................42
16.8 Replacing the Unit assy (1)......................................................................................................43
16.9 Input of temperature coefficient data ..................................................................................... 43
16.10 Replacement of the level...................................................................................................... 43
17 Replacing the Force coil assy (L1)................................................................44
17.1 Dismantling ............................................................................................................................... 44
18 Assembly ........................................................................................................44
19 Dismantling/ Assembling the Weight loader assy (10) ...............................46
19.1 Dismantling ............................................................................................................................... 46
19.2 Assembly...................................................................................................................................48
19.3 Adjustment of the pin height of the calibration weight loading ..........................................48
20 Balance Adjustment.......................................................................................49
20.1 Adjustment of the Assy,Detector (U8) Height ....................................................................... 49
20.2 Adjustment of tilt errors...........................................................................................................50
20.3 Adjustment of Corner Load..................................................................................................... 51
21 Performance Inspection.................................................................................52
21.1 Repeatability ............................................................................................................................. 52
21.2 Corner load error ......................................................................................................................52
21.3 Built-in weight calibration........................................................................................................52
21.4 Linearity..................................................................................................................................... 53
21.5 Tilt error..................................................................................................................................... 53
22 Component Replacement Precautions.........................................................54
23 Drawing ...........................................................................................................55
24 11. Trouble shooting......................................................................................59
24.1 Information for Inferring the Cause of Board Failure ........................................................... 61
24.2 1Assy,Display (B4) ................................................................................................................... 61
24.3 Assy,Analog (B3)...................................................................................................................... 61
24.4 Voltages of each part (reference values) ...............................................................................62
24.5 Assy,I/F (B5)..............................................................................................................................62
24.6 Voltages of each part (reference values) ...............................................................................62
24.7 Writing in Simple Linear Coefficients (temporary, rough adjustment of linearity)............ 63
25 Adjustment of Linearity .................................................................................64
26 Editing EEPROM data ....................................................................................66
26.1 Using “Edit” .............................................................................................................................. 66
PBJ_N-SH-e-1810.docx 4
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1 Basic Information
The device must be repaired only by trained specialist staff or personnel with professional
formation (such as a repair-specialist accredited by law concerning verification). The service
manual is obligatory for repair work. After repair, original conditions of the device have to be
restored. Only original spare parts should be used.
Instructions about conformity-evaluated scales:
Repair must be carried only at 100% compliance with the type approval. A violation of this
specification will result in a loss of the type approval! After successful repair the balance will
have to be reverified before it can be used again in a statutorily regulated field.
Detailed instructions about conformity-evaluated scales:
Repair must be carried only at 100% compliance with the type approval. A violation of this
specification will result in a loss of the type approval!
After successful repair the balance will have to be reverified before it can be used again in a
statutorily regulated field.
2 Introdution
-
This service manual covers the PBJ_N series and is edited for the authorized servicing
personnel.
Note all rights are reserved. Copying any part of this manual is prohibited without our
permission.
In this lineup it is an eco product, Therefore, it is not intended to represent the repair manual
in detail, since the construction of the balance is very simple. It is therefore only referring to
the list of related to disposal spare parts.
PBJ_N-SH-e-1810.docx 6
3 Appliance overview
Models with readability d = 0.001 g:
Models with readability d ≥ 0.01 g:
Windshield
Weighing pan
Display
Keyboard
Levelling screw
7 PBJ_N-SH-e-1810.docx
3.1 Keyboard overview
In weighing mode:
Button
Description
Pressed once and released
Keep pressed for about 3
seconds
[ON/OFF]
Switches between the
operation and standby modes.
Exit menu / Return to weighing
mode
[CAL]
Invokes adjustment or menu
selection. (*1)
To display the menu
element recently set.
[TARE]
Taring / Setting to zero
No operation
[UNIT]
Switch over weighing unit (*3)
No operation
[PRINT]
Issue of weighing value to
external appliances (printer,
PC)
Issue of date and time to
external appliances.
*1 This key is used to set a value when percent (%), number of pieces (PCS), specific
weight
of solids (▼d) or specific weight of liquid (d) is displayed.
*3 Units different than „g” must be first set in the balance, before they can be used for
measurements. Only gram (g), percent (%) and number of pieces (PCS) are factory set.
ESC
ON/OFF
MENU
CAL
TARE/
UNIT
PRINT
PBJ_N-SH-e-1810.docx 8
3.2 In menu:
Button
Description
Pressed once and released
Keep pressed for about 3
seconds
[ON/OFF]
To return to a submenu or
weighing mode.
Return to weighing mode
[CAL]
Moves to the next menu item.
To display the menu
element recently set.
[TARE]
To select or set the menu
element recently displayed.
No operation
[UNIT]
Entering numeric values:
Increases the numeric value
of flashing digit by 1.
No operation
[PRINT]
Entering numeric values: To
go to the next position.
No operation
3.3 Numeric entry
Button
Description
Function
Navigation button
Increase flashing digit
Navigation button
Digit selection to the right
Navigation button
Confirm entry
ESC
Cancel input
With numerical input the indicator [#] appears.
„SET“ indicates that the value has been saved successfully.
„ERR“ means that the value could not be saved successfully; back to menu by
and repeat enter.
ESC
ON/OFF
MENU
CAL
TARE/
UNIT
PRINT
9 PBJ_N-SH-e-1810.docx
3.4 Setting the decimal point when entering numerical values
Entering a decimal point is necessary only for determining the specific gravity or if a multiplier
shall be defined for the user-defined unit.
Repeat actuating the button until the last digit flashes. Actuate the button again in
order to call up the decimal point setting mode. The reversed triangle symbol ▼or the current
decimal point flashes.
Actuate the button in order to move the decimal point to the required position by one
digit each.
Actuate the button to define the position of the decimal point. The message „SEt“
which appears for a short period of time indicates that setting has been completed.
PRINT
PRINT
UNIT
TARE/
PBJ_N-SH-e-1810.docx 10
3.5 Overview of display
Display
Designation
Description
Indicates that the weighed value is stable. (*1) It marks the
currently selected element during menu element selection.
Tare symbol
Informs about setting an initial tare value.
Weight symbol
It is displayed during adjusting the measuring range. It
indicates adjusting settings during menu selection. Flashes
prior to start of automatic adjustment.
Note:
If automatic adjusting of measuring range is not activated, a
user must perform it when this symbol flashes.
with built-in weight (PBJ models refer to chapter
9.31.1)
with external weight (PBS models refer to chapter
Fehler! Verweisquelle konnte nicht gefunden werden.).
[ ]
Brackets
The non-calibrated value is given in brackets in calibrated
scales.
Number symbol
Indicates numeric value entry.
Menu symbol
Appears during menu selection. Always shown when the
menu is locked.
Asterisk
Indicates that the displayed numeric value is not a mass
value.
Communication
symbol
Is lit up during communication with external appliances via
RS-232C cable. Shown when communication functions are
ON.
▼
Inverse triangle
symbol
Indicates the setting of specific weight measurement. It is
used as an alternative to the decimal point.
→0←
Zero indicator
Animal symbol
Shows the setting of animal weighing function.
Automatic storage
and zeroing symbol
Shows the setting of automatic saving and zeroing function.
M
Memory Symbol
Balance is in formula mode
Auto Print symbol
Displays set-up of the Auto Print function.
Standby mark
Appears when the balance power supply is in stand-by
mode. It is also displayed when operational function
changes into stand-by mode.
*1 Stabilisation symbol
When the stabilisation symbol is illuminated for a long time, the displayed value may
oscillate when a weight is slowly changed or stabilisation detection range is set to high
value.
Capacity display
Display of units
Stability display
11 PBJ_N-SH-e-1810.docx
4 Basic Information (General)
4.1 Proper use
The balance you purchased is intended to determine the weighing value of material to be
weighed. It is intended to be used as a “non-automatic balcance”, i.e. the material to be
weighed is manually and carefully placed in the centre of the weighing pan.. As soon as a
stable weighing value is reached the weighing value can be read.
4.2 Improper Use
Do not use balance for dynamic add-on weighing procedures, if small amounts of goods to be
weighed are removed or added. The “stability compensation“ installed in the balance may
result in displaying an incorrect measuring value! (Example: Slowly draining fluids from a
container on the balance.)
Do not leave permanent load on the weighing pan. This may damage the measuring system.
Impacts and overloading exceeding the stated maximum load (max) of the balance, minus a
possibly existing tare load, must be strictly avoided. Balance may be damage by this.
Never operate balance in explosive environment. The serial version is not explosion
protected.
The structure of the balance may not be modified. This may lead to incorrect weighing results,
safety-related faults and destruction of the balance.
The balance may only be used according to the described conditions. Other areas of use
must be released by KERN in writing.
4.3 Warranty
Warranty claims shall be voided in case
Our conditions in the operation manual are ignored
The appliance is used outside the described uses
The appliance is modified or opened
Mechanical damage or damage by media, liquids, natural wear and tear
The appliance is improperly set up or incorrectly electrically connected
The measuring system is overloaded
PBJ_N-SH-e-1810.docx 12
4.4 Monitoring of Test Resources
In the framework of quality assurance the measuring-related properties of the balance and, if
applicable, the testing weight, must be checked regularly. The responsible user must define a
suitable interval as well as type and scope of this test. 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. In KERN's accredited DKD calibration laboratory test
weights and balances may be calibrated (return to the national standard) fast and at
moderate cost.
5 Basic Safety Precautions
5.1 Pay attention to the instructions in the Operation Manual
Carefully read this operation manual before setup and commissioning, even if you are already
familiar with KERN balances.
5.2 Personnel training
The appliance may only be operated and maintained by trained personnel.
6 Transport and storage
6.1 Testing upon acceptance
When receiving the appliance, please check packaging immediately, and the appliance itself
when unpacking for possible visible damage.
6.2 Packaging
Keep all parts of the original packaging for a possibly required return.
Only use original packaging for returning.
Prior to dispatch disconnect all cables and remove loose/mobile parts.
Reattach possibly supplied transport securing devices.
Secure all parts such as the glass wind screen, the weighing platform,
power unit etc. against shifting and damage.
13 PBJ_N-SH-e-1810.docx
7 Unpacking, Setup and Commissioning
7.1 Installation Site, Location of Use
The balances are designed in a way that reliable weighing results are achieved in common
conditions of use.
You will work accurately and fast, if you select the right location for your balance.
Therefore, observe the following for the installation site:
Operate the device only indoors.
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. Non-permitted
condensation (condensation of air humidity on the appliance) may occur if a cold appliance is
taken to a considerably warmer environment. In this case, acclimatize the disconnected
appliance for ca. 2 hours at room temperature.
Avoid static charge of goods to be weighed or weighing container.
If electro-magnetic fields or static charge occur, or if the power supply is unstable major
deviations on the display (incorrect weighing results) are possible. In that case, the location
must be changed.
7.2 Unpacking / Scope of delivery
Remove device and accessories carefully from packaging, remove
packaging material and place device at the planned work place. Verify that
there has been no damage and that all packing items are present.
PBJ_N-SH-e-1810.docx 14
Scope of delivery / serial accessories:
Models with readability d = 0.001 g:
Models with readability d ≥ 0.01 g:
Mains adapter
Operating instructions
Menu overview
Carrier weighing pan
Protective cover
Weighing pan
2 Fixiing screws
Protection hood
Wiindshield
2 screws
Main weighing unit
15 PBJ_N-SH-e-1810.docx
7.3 Placing
Remove transport guard (models PBJ)
To loosen the transport guard, turn both transport screws [1] anti-clockwise until they are
locked (refer to sign [2]).
For transport, turn both transport screws clockwise until they are locked.
Mount safety hood
Remove protective foil from adhesive strips and mount the safety hood so that it does not
contact the weighing plate.
Levelling
Turn in all three foot screws [1] as far as they go.
Slightly press down the left front side of the scale and turn out the two front foot screws until
the air bubble [3] in the spirit level [2] is within the prescribed circle.
PBJ_N-SH-e-1810.docx 16
While continuing to exert a slight pressure to the front side of the scale, turn out the rear foot
screw until the scale stands in stable position.
Check levelling regularly.
Installation of weighing plate
Models with readability d ≥ 0.01 g:
17 PBJ_N-SH-e-1810.docx
Models with readability = 0.001 g:
Remove rubber plug as shown in picture.
Attach wind guard and fix it by means of
screws.
Install weighing pan as per illustration.
Note the correct position.
Place the wind guard cover.
PBJ_N-SH-e-1810.docx 18
7.4 Mains connection
Power is supplied via the external mains adapter. The stated voltage value must be the same
as the local voltage.
Only use original KERN mains adapters. Using other makes requires consent by KERN.
Models PBJ:
Prior to mains connection, loosen the transport guard screws at the scale
according to the sign in any case, see chapter 7.3
7.5 Switch power supply on
19 PBJ_N-SH-e-1810.docx
7.6 Connection of peripheral devices
Before connecting or disconnecting of additional devices (printer, PC) to the data interface,
always disconnect the balance from the power supply.
With your balance, only use accessories and peripheral devices by KERN, as they are ideally
tuned to your balance.
Terminal for external devices:
Interfaces at the balance
back
1
RS-232C interface
2
DATA IO interface
3
AUX interface
4
DC-IN connection
5
Keyboard interface
7.7 Initial Commissioning
In order to obtain exact results with the electronic balances, your balance must have reached
the operating temperature (see warming up time chap. During this warming up time the
balance must be connected to the power supply (mains, accumulator or battery).
The accuracy of the balance depends on the local acceleration of gravity.
Strictly observe hints in chapter Adjustment.
5
4
3
2
1
PBJ_N-SH-e-1810.docx 20
8 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 for the first commissioning, after each change of location as well as in case of fluctuating
environment temperature. To receive accurate measuring values it is also recommended to
adjust the balance periodically in weighing operation.
Observe stable environmental conditions. A warming up time (see
chapter 1) is required for stabilization. Ensure that there are no
objects on the weighing pan.
8.1 Manual adjustment by CAL button
The scales have been set by the manufacturer so that adjustment can be started directly from
the weighing mode using the CAL button.
Models PBJ: Adjustment with internal weight
Other adjustment procedures can be activated in the menu.
8.2 Adjustment with internal weight
Condition: Menu setting „I.CAL“ / Menu element 1
In weighing mode press . I-CAL is displayed.
If „I-CAL“ is not displayed, press to return into weighing mode and activate
menu element 1, see menu overview.
Table of contents
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