KERN KFB-TM, KFN-TM Service Manual

KERN & Sohn GmbH

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

Tel: +49-[0]7433- 9933-0
Fax: +49-[0]7433-9933-149
Internet: www.kern-sohn.com

Servicemanual
Display Unit

KERN KFB/KFN-TM

Version 1.0

03/2018
GB

Distributør:
Impex Produkter AS
Gamle Drammensvei 107
1363 Høvik
www.impex.no
[e-mail]
Tel.: [phone]

KFB-TM/KFN-TM-SH-e-1410 - 2 -

GB

KERN KFB/KFN-TM

Version 1.0 01/2015

Servicemanual

Content

1 Basic Information ........................................................................................... - 3 -

2 Introdution ...................................................................................................... - 3 -

3 INSTALLATION ............................................................................................... - 4 -

3.1 Installation .............................................................................................................................. - 4 -

4 Appliance overview ........................................................................................ - 5 -

4.1 KFB-TM: Synthetic finish ...................................................................................................... - 5 -

4.2 KFN-TM: Stainless steel finish ............................................................................................. - 6 -

4.3 Keyboard overview ................................................................................................................ - 7 -

Numerical input via the navigation buttons ................................................................ - 8 -

Overview of display ..................................................................................................... - 8 -

5 Menu ................................................................................................................ - 9 -

5.1 Overview non verifiable weighing systems (contacts of circuit board [K1] not short-

circuited) ........................................................................................................................................... - 10 -

5.2 Overview verified weighing systems (contacts of circuit board [K1] short-circuited by

means of jumper) ............................................................................................................................. - 13 -

6 Service, maintenance, disposal .................................................................. - 17 -

6.1 Clean ..................................................................................................................................... - 17 -

6.2 Service, maintenance .......................................................................................................... - 17 -

6.3 Disposal ................................................................................................................................ - 17 -

6.4 Error messages.................................................................................................................... - 17 -

7 Data output RS 232C .................................................................................... - 19 -

7.1 Technical data ...................................................................................................................... - 19 -

7.2 Printer mode ......................................................................................................................... - 19 -

7.3 Output log (continuous output) ......................................................................................... - 20 -

7.4 Remote control instructions ............................................................................................... - 20 -

8 Instant help ................................................................................................... - 21 -

9 Installing display unit / weighing bridge .................................................... - 22 -

9.1 Technical data ...................................................................................................................... - 22 -

9.2 Weighing system design .................................................................................................... - 22 -

9.3 How to connect the platform .............................................................................................. - 23 -

9.4 Configure display unit ......................................................................................................... - 25 -

Verified weighing systems (contacts of circuit board [K1] short-circuited by means of

jumper) - 25 -

Non verifiable weighing systems (contacts of circuit board [K1] not short-circuited ) .... -

30 -

10 MAINTENENCE ......................................................................................... - 33 -

10.1 General ................................................................................................................................. - 34 -

- 3 - KFB-TM/KFN-TM-SH-e-1410

10.2 Error Codes .......................................................................................................................... - 34 -

10.3 Check the Load cell ............................................................................................................. - 35 -

10.4 Check Indicator Voltages .................................................................................................... - 35 -

AC Power ................................................................................................................... - 35 -

Adaptor Voltage ........................................................................................................ - 35 -

PCB Input Voltage ...................................................................................................... - 36 -

Check Battery Voltage and Charging Voltage ............................................................ - 36 -

10.5 Problems and Solutions ..................................................................................................... - 37 -

11 10. TROUBLE SHOOTING ........................................................................ - 39 -

11.1 No Power .............................................................................................................................. - 39 -

No Display ........................................................................................................................................ - 40 -

Battery not charging ....................................................................................................................... - 41 -

11.2 Not Weighing ........................................................................................................................ - 42 -

11.3 Unstable ................................................................................................................................ - 43 -

12 11. CIRCUIT DIAGRAM ............................................................................. - 44 -

13 DRAWING .................................................................................................. - 48 -

13.1 Drawing KFB-TM .................................................................................................................. - 48 -

13.2 Parts List .............................................................................................................................. - 49 -

13.3 Drawing KFN-TM .................................................................................................................. - 50 -

13.4 Parts List .............................................................................................................................. - 51 -

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 EOA 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.

KFB-TM/KFN-TM-SH-e-1410 - 4 -

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.

3 INSTALLATION

Precautions

 The weighing indicator is a precision electronic instrument, handle it

carefully.

 Do not install the scale in direct sunlight.
 Verify the local voltage and receptacle type are correct for

the scale.

 Only use original adaptor, other could cause damage to the scale.
 Pluggable equipment must be installed near an easily accessible

socket outlet.

 Avoid unstable power sources. Do not use near large users of

electricity such as welding equipment or large motors.

 Avoid sudden temperature changes, vibration, wind and water.
 Avoid heavy RF noise.
 Keep the indicator clean.

3.1 Installation

 Place the Indicator on a table or connect with proper stand.
 Connect the plat form load cell cable in to the indicator load cell connecter. Load cell

connecter is locating back side of the indicator.

 Connect the adaptor pin in to the indicator adaptor jack.

Adaptor jack is locating, back side of the indicator.

 Adaptor connects into your AC power socket. Pluggable

equipment must be installed near an easily accessible socket outlet with a protective
ground/ earth contact.

 Turn on the On/Off key. If you want to turn off, press the key again.
 Display will be show the scale capacity and will be starting self checking.
 After self checking, display will be come to normal weighing mode.
 Warm-up time of 15 minutes stabilizes the measured values after switching on.
 Calibrate with exact calibration weights, minimum 1/3 of the scale capacity want to

use for calibration. For calibration see details in parameter.

- 5 - KFB-TM/KFN-TM-SH-e-1410

Then you can start your operation

4 Appliance overview

4.1 KFB-TM: Synthetic finish

1. Status of rechargeable battery

2. Keyboard

3. Weight display

4. Tolerance margin, see chap. 7.7

5. Weighing unit

6. RS-232

7. Input connection load cell cable

8. Guide rail support base / stand

9. End stop support base / stand

10. Mains adapter connection

KFB-TM/KFN-TM-SH-e-1410 - 6 -

11. Adjustment switch

4.2 KFN-TM: Stainless steel finish

1. Status of rechargeable battery

2. Keyboard

3. Weight display

4. For tolerance mark see chap. 7.7

5. Weighing unit

6. Input connection load cell cable

7. Mains adapter connection

- 7 - KFB-TM/KFN-TM-SH-e-1410

4.3 Keyboard overview

Key

Function

 Turn on/off

 Zeroing

Navigation button

 Confirm entry

 Taring

Navigation key 

 At numeric input increase flashing digit
 Scroll forward in menu

 Display sum total

Navigation key 

 Digit selection to the right

 Add weighing value to summation memory

Navigation key 

 Digit selection to the left

 Calculate weighing data via interface

C

 Delete

 Change between gross  and net weight

ESC

 Back to menu/weighing mode

 Call up animal weighing function

 Call up weighing with tolerance range

 Delete total added memory

KFB-TM/KFN-TM-SH-e-1410 - 8 -

Numerical input via the navigation buttons

 Press and current setting will be displayed. The first digit will be flashing and is

ready for changing.

 If you do not wish to change the first digit, press and the second digit will start

flashing.
Each time you press , the display will move to the subsequent digit, after the last

digit the display will return to the first digit.

 To change the selected (flashing) digit, press repeatedly until the desired value is

displayed. Then press to access further digits and change them by .

 Complete your entry by .

Overview of display

Display

Significance

Battery very low

STABLE

Stability display

ZERO

Zero indicator

GROSS

Gross weight

NET

Net weight

AUTO

Automatic add-up enabled

Kg

Weighing unit

M+

Totalisation

LED

+ / / -

Indicators for weighing with tolerance range

- 9 - KFB-TM/KFN-TM-SH-e-1410

5 Menu

The application of the display unit as a verified weighing system requires that you short­circuit the two contacts [K1] of the circuit board, using a jumper. To that effect, a menu for
verified weighing systems is available. For menu layout see chap. 8.2.
There is no jumper for weighing systems that cannot be verified. To that effect, a menu is
available for weighing systems that cannot be verified, Menu layout

see chap. 8.1

Navigation in the menu:

Call up menu

 Switch-on balance and during the selftest press .

 Press , , subsequently, the first menu block

„PO CHK“ will be displayed.

Select menu block

 With help of , the individual menu items can be selected

one after the other.

Select setting

 Confirm selected menu item by pressing . The current

setting will be displayed.

Change settings

 To change to the available settings, press the navigations

keys as described in chap. 2.1.

Acknowledge setting /
exit the menu

 Either save by pressing or cancel by pressing .

Return to weighing
mode

 Press repeatedly to exit menu.

KFB-TM/KFN-TM-SH-e-1410 - 10 -

5.1 Overview non verifiable weighing systems
(contacts of circuit board [K1] not short-circuited)

Menu block
Main menu

Menu item
Submenu

Available settings / explanation

PO CHK

Weighing with
tolerance range,
see chap. 7.7

nEt H

Upper limit value „Tolerance check weighing“, input see

chap. 7.7.1

nEt LO

Lower limit value „Tolerance check weighing“, input see

chap. 7.7.1

PCS H

Upper limit value „Tolerance check counting“, input see

chap. 7.7.2

PCS L

Lower limit value „Tolerance check counting“, input see

chap. 7.7.2

BEEP

no

Acoustic signal for weighing with tolerance range
switched off

ok

Audio sound when load is within tolerance limits

nG

Audio sound when load is beyond tolerance limits

P1 REF

Zero point
settings

A2n0

Automatic zero point correction (Autozero) by changing the
display, digits selectable (0.5d, 1d, 2d, 4d)

0AUto

Zero setting range
Load range where the display after switching-on the
balance is set to zero.

Selectable 0, 2, 5, 10, 20, 30, 50, 100 %

0rAGE

Zero setting range
Load range where the display is set to zero by pressing

. Selectable 0, 2, 4, 10 , 20* , 50, 100%.

0tArE

Automatic taring „on / off“, taring range adjustable in menu

item „0Auto“.

SPEEd

Not documented

Zero

Zero point setting

P2 COM

Interface
parameter

MODE

CONT
S0 off

Continuous data output,
selectable “send zero” yes / no

S0 on

ST1

One output for stable weighing value

STC

Continuous data output of stable weighing
values

PR1
Output after pressing

- 11 - KFB-TM/KFN-TM-SH-e-1410

PR2

Manual totalizing, see chap. 7.8.

Press and the weighing value will be
added to the summation memory and issued.

AUTO*

For automatic add-up see chap. 7.9.

This function is used to issue and add individual
weighing values automatically to the summation
memory on unloading of weighing scale.

ASK

For remote control commands, see chap. 10.4

wirel

Not documented

BAUD

Available Baudrate: 600, 1200, 2400, 4800, 9600*

Pr

7E1

7 bits, even parity

7o1

7 bits, odd parity

8n1*

8 bits, no parity

PTYPE
tPUP*

Standard printer setting

LP50

Not documented

Lab

Lab x

For data output format, see chap.8.2, tab. 1
Prt

Prt x

LAnG

eng*

Standard settings English

chn

P3 CAL

Configuration
data
see chap. 12.4

COUNT

Display internal resolution

DECI

Position of the decimal dot

DUAL

Setting balance type, capacity (Max) and readability (d)

off

Single-range balance

R1 inc

Readability

R1 cap

Capacity

on

Dual range balance

R1 inc

Readability 1st weighing range

R1 cap

Capacity 1st weighing range

KFB-TM/KFN-TM-SH-e-1410 - 12 -

R2 inc

Readability 2nd weighing range

R2 cap

Capacity 2nd weighing range

CAL

noLin

For adjustment, see chap. 6.9.2

Liner

For linearization, see chap. 6.10.2

GrA

Not documented

P4 OTH

LOCK
on

Keyboard lock enabled, see chap. 7.11

off*

Keyboard lock disabled

ANM
on

Animal weighing enabled, see chap. 7.10

off*

Animal weighing disabled

P5 Unt

Switch-over
weighing unit,
see chap. 7.5

kg
on* off

g
on off*

lb
on

off*

oz
on

off*

tJ
on

off

HJ
on off

P6 xcl

Not documented

P7 rst
Use to reset balance settings to factory default.

P8 uwb

Not documented

Factory settings are marked by *.

- 13 - KFB-TM/KFN-TM-SH-e-1410

5.2 Overview verified weighing systems
(contacts of circuit board [K1] short-circuited by means of jumper)

In verified weighing systems the access to „P2 mode and „P4 tAr“ is locked.

KERN KFB-TM:

To disable the access lock, destroy the seal and actuate the adjustment switch.
Position of the adjustment switch see chap. 6.11.

KERN KFN-TM:
In order to unlock the access, the seal must be destroyed and both contacts of the

printed circuit board [K2] must be short-circuited by a jumper, see chap. 6.11.
Attention:

After destruction of the seal the weighing system must be re-verified by an
authorised agency and a new verification wire/seal mark fitted before it can be
reused for applications subject to verification.

Menu block
Main menu

Menu item
Submenu

Available settings / explanation

PO CHK
Weighing with

tolerance range,
see chap. 7.7

nEt H

Upper limit value „Tolerance check weighing“, input see

chap. 7.7.1

nEt LO

Lower limit value „Tolerance check weighing“, input see

chap. 7.7.1

PCS H

Upper limit value „Tolerance check counting“, input see

chap. 7.7.2

PCS L

Lower limit value „Tolerance check counting“, input see

chap. 7.7.2

BEEP

no

Acoustic signal for weighing with tolerance
range switched off

ok

Audio sound when load is within tolerance
limits

ng

Audio sound when load is beyond tolerance
limits

P1 COM

Interface
parameter

MODE

CONT
S0 off

Continuous data output,
selectable “send zero” yes / no

S0 on

ST1

One output for stable weighing value

STC

Continuous data output of stable weighing
values

KFB-TM/KFN-TM-SH-e-1410 - 14 -

PR1
Output after pressing

PR2

Manual totalizing, see chap. Fehler!

Verweisquelle konnte nicht gefunden
werden.

Press and the weighing value will be
added to the summation memory and issued.

AUTO

For automatic totalizing see chap. Fehler!

Verweisquelle konnte nicht gefunden
werden.

This function is used to issue and add
individual weighing values automatically to the
summation memory on unloading of weighing
scale.

ASK

For remote control commands, see chap. 7.4

wireless

Not documented

baud

Available Baudrate: 600, 1200, 2400, 4800, 9600

Pr

7E1

7 bits, even parity

7o1

7 bits, odd parity

8n1

8 bits, no parity

PtYPE
tPUP

Standard printer setting

LP50

Not documented

Lab

Lab x

Details see following table 1
Prt

Prt x

Lang
Eng*

Standard setting English
Chn

P2 mode

Konfigurations­daten

SiGr

Single-range balance

COUNT

Display internal resolution

DECI

Position of the decimal dot

Div.

Readability [d] / verification value[s]

CAP

Balance capacity [Max]

- 15 - KFB-TM/KFN-TM-SH-e-1410

CAL

noLin

Adjustment, see chap. Fehler!

Verweisquelle konnte nicht
gefunden werden.

LinEr

Linearisation, see chap. Fehler!

Verweisquelle konnte nicht
gefunden werden.

GrA

Not documented

dUAL 1

Dual range balance

Balance with two weighing ranges and different maximum load
and weighing ranges and interval sizes but only one load­supporting pan, whereby each range extends from zero to the
respective maximum capacity. When load is removed, weighing
scales will remain in 2nd range.

COUNT

Display internal resolution

DECI

Position of the decimal dot

div.
div 1

Readability [d] / verification value [e]

1. weighing range

div 2

Readability [d] / verification value [e]

2. weighing range

CAP
CAP 1

Weighing scale capacity [max]

1. Weighing range

CAP 2

Weighing scale capacity [max]

2. Weighing range

CAL

noLin

Adjustment, see chap. 6.9

LinEr

For linearization, see chap. Fehler!

Verweisquelle konnte nicht
gefunden werden.

GrA

Not documented

dUAL 2

Multi-interval balance

Weighing scales with one weighing range subdivided into partial
weighing ranges, each providing a different scale interval. The
scale interval depends on the applied load and is automatically
changed during loading and unloading.

COUNT

Display internal resolution

DECI

Position of the decimal dot

div.

div 1

Readability [d] / verification value [e]

1. weighing range

KFB-TM/KFN-TM-SH-e-1410 - 16 -

div 2

Readability [d] / verification value [e]

2. weighing range

CAP
CAP 1

Weighing scale capacity [max]

1. Weighing range

CAP 2

Weighing scale capacity [max]

2. Weighing range

CAL

noLin

Adjustment, see chap. Fehler!

Verweisquelle konnte nicht
gefunden werden.

LinEr

Linearisation, see chap. Fehler!

Verweisquelle konnte nicht
gefunden werden.

GrA

Not documented

P3 OTH
s. Kap. 7.10 / 7.11

LOCK

on

Keyboard lock enabled

off

Keyboard lock disabled

ANM

on

Animal weighing enabled

off

Animal weighing disabled

P4 tAr
Restricted taring

range

Press , the current setting will be displayed. Using the
navigation buttons (see chap. 2.1.1) select the desired setting, the
active digit is flashing.

Confirm input by .

P5 St
Follow up tare

St on

Follow up tare switched on

St off

Follow up tare switched off

P6 SP

7.5, 15, 30

Not documented

Tab. 1. Printout examples Standard printer

Lab

Prt

0 1 2

3

0~3

*******************
GS: 5.000kg

*******************
NT: 5.000kg

**********************
GS: 5.000kg

**********************
NT: 5.000kg

- 17 - KFB-TM/KFN-TM-SH-e-1410

*******************

TW: 5.000kg
GW: 10.000kg
*******************

TOTAL: 10.000kg
**********************

TW: 5.000kg
GW: 10.000kg
TOTAL: 10.000kg
**********************

4~7

*******************
No.: 1
GS: 5.000kg
*******************

*******************
No.: 1
NT: 5.000kg
TW: 5.000kg
GW: 10.000kg
*******************

**********************
No.: 1
GS: 5.000kg
TOTAL: 10.000kg
**********************

**********************
No.: 1
NT: 5.000kg
TW: 5.000kg
GW: 10.000kg
TOTAL: 10.000kg
**********************

GS / GW

Gross weight

NO

Number weighing processes

NT

Net weight

TOTAL

Total of all individual weighings

TW

Tare weight

6 Service, maintenance, disposal

6.1 Clean

 Before cleaning, disconnect the appliance from the operating voltage.
 Do not use aggressive detergents (solvents or similar).

6.2 Service, maintenance

The appliance may only be opened by trained service technicians who are authorized by
KERN.

Before opening, disconnect from power supply.

6.3 Disposal

Disposal of packaging and appliance must be carried out by operator according to valid
national or regional law of the location where the appliance is used.

6.4 Error messages

Error

message

Description

Possible causes

- - - - -

Maximum load exceeded

 Unload weighing system or reduce

KFB-TM/KFN-TM-SH-e-1410 - 18 -

- - ol - -

preload.

Err 1

Incorrect data input

 Follow format “yy:mm:dd“

Err 2

Incorrect time entry

 Follow format “hh:mm:ss“

Err 4

Zeroing range exceeded due to
switching-on balance or pressing

(normally 4% max)

 Object on the weighing plate
 Overload when zeroing

Err 5

Keyboard error

Err 6

Value outside the A/D changer
range

 Weighing plate not installed

 Damaged weighing cell

 Damaged electronics

Err 9

Stability display does not appear

 Check the environmental conditions.

Err 10

Communication error

 No data

Err 15

Gravitation error

 Range 0.9 ~ 1.0

Err 17

Taring range exceeded

 Reduce load

Fai l h /
Fai l l

Adjustment error

 Repeat adjustment.

Err P

Printer error

 Check communication parameters

Ba lo /
Lo ba

Battery very low

 Recharge battery

Should other error messages occur, switch balance off and then on again. If the error
message remains inform manufacturer.

- 19 - KFB-TM/KFN-TM-SH-e-1410

7 Data output RS 232C

You can print weighing data automatically via the RS 232C interface or manually by pressing

via the interface according to the setting in the menu.

This data exchange is asynchronous using ASCII - Code.

The following conditions must be met to provide successful communication between the
weighing system and the printer.

 Use a suitable cable to connect the display unit to the interface of the printer.

Faultless operation requires an adequate KERN interface cable.

 Communication parameters (baud rate, bits and parity) of display unit and printer

must match. For a detailed description of interface parameters see chap. Fehler!

Verweisquelle konnte nicht gefunden werden., menu block „P1 COM“ or ‚“P2
COM“

7.1 Technical data

Connection

9 pin d-subminiature bushing

Pin 2 input
Pin 3 output
Pin 5 signal earth

Baud rate

Optional 600/1200/2400/4800/9600

Parity

8 bits, no parity / 7 bits, even parity / 7 bits, odd parity

7.2 Printer mode

Printout examples (KERN YKB-01N):

 Weighing

ST, GS 1.000kg

KFB-TM/KFN-TM-SH-e-1410 - 20 -

Symbols:

ST

Stable value

US

Instable value

GS / GW

Gross weight

NT

Net weight

TW

Tare weight

NO

Number weighing processes

TOTAL

Total of all individual weighings

<lf>

Space line

<lf>

Space line

 Counting

7.3 Output log (continuous output)

 Weighing

HEADER1: ST=STABLE， US=UNSTABLE

HEADER2: NT=NET， GS=GROSS

7.4 Remote control instructions

Command

Function

Printout examples

****************************

PCS 100

- 21 - KFB-TM/KFN-TM-SH-e-1410

S

Stable weighing value for the weight is sent via
the RS232 interface

ST,GS 1.000KG

W

Weighing value for the weight (stable or
unstable) is sent via the RS232 interface

US,GS 1.342KG
ST,GS 1.000KG

T

No data are sent, the balance carries out the
tare function.

-

Z

No data are sent, the zero-display appears.

-

P

Quantity will be sent via the RS232-interface

10PCS

8 Instant help

In case of an error in the program process, briefly turn off the display unit and
disconnect from power supply. The weighing process must then be restarted from the

beginning.

Help:

Fault

Possible cause

The displayed weight does not
glow.

 The display unit is not switched on.

 Mains power supply interrupted (mains cable defective).

 Power supply interrupted.

 (Rechargeable) batteries are inserted incorrectly or

empty

 No (rechargeable) batteries inserted.

The displayed weight is
permanently changing

 Draught/air movement

 Table/floor vibrations

 Weighing pan has contact with other objects.
 Electromagnetic fields / static charging (choose different

location/switch off interfering device if possible)

The weighing result is
obviously incorrect

 The display of the balance is not at zero

 Adjustment is no longer correct.

KFB-TM/KFN-TM-SH-e-1410 - 22 -

 Great fluctuations in temperature.

 Warm-up time was ignored.

 Electromagnetic fields / static charging (choose different

location/switch off interfering device if possible)

Should other error messages occur, switch display unit off and then on again. If the error
message remains inform manufacturer.

9 Installing display unit / weighing bridge

 Installation / configuration of a weighing system must be carried out

by a well acquainted specialist with the workings of weighing
balances.

9.1 Technical data

Supply voltage:

5 V/150mA

Max. signal voltage

0-10 mV

Zeroing range

0-2 mV

Sensitivity

2-3 mV/V

Resistance parameter

80 - 100 Ω, max 4 items per 350 Ω load cell

9.2 Weighing system design

The display unit is suitable for connection to any analogue platform in compliance with the
required specifications.

The following data must be established before selecting a weighing cell:

 Weighing balance capacity

This usually corresponds to the heaviest load to be weighed.

 Preload

This corresponds to the total weight of all parts that are to be placed on the
weighing cell such as upper part of platform, weighing pan etc.

 Total zero setting range

This is composed of the start-up zero setting range (± 2%) and the zero setting
range available to the user via the ZERO-key (2%). The total zero setting range
equals therefore 4 % of the scale’s capacity.

The addition of weighing scales capacity, preload and the total zero setting range
give the required capacity for the weighing cell.
To avoid overloading of the weighing cell, include an additional safety margin.

- 23 - KFB-TM/KFN-TM-SH-e-1410

 Smallest desired display division
 Verifiability, if required

The application of the display unit as a verified weighing system requires that you
short-circuit the two contacts [K1] of the circuit board, using a jumper; for position
see chap. Fehler! Verweisquelle konnte nicht gefunden werden..
Remove the jumper for weighing systems not able to be verified.

9.3 How to connect the platform

 Disconnect the display unit from the power supply.
 Solder the individual leads of the load cell cable onto the circuit board. See diagrams

below.

EXC+

SEN+

SEN-

EXC­SIG+

SIG-

SHIELD

7

6

3

2

LOAD CELL

KFB-TM/KFN-TM-SH-e-1410 - 24 -

PIN

Loadcell

6- conductor

4- conductor

7

EXC+

EXC+

6

SEN+

5

EXC-

EXC-

4

SEN-

3

SHIELD

SHIELD

2

SIG-

SIG-

1

SIG+

SIG+

- 25 - KFB-TM/KFN-TM-SH-e-1410

9.4 Configure display unit

Verified weighing systems

(contacts of circuit board [K1] short-circuited by means of jumper)

For menu overview see chap. 5.2.
In verified weighing systems the menu item for calibration „P2 mode“ is blocked.

KERN KFB-TM:

To disable the access lock, destroy the seal and actuate the adjustment switch.
Position of the adjustment switch see chap. Fehler! Verweisquelle konnte nicht

gefunden werden.
KERN KFN-TM:

To override the blocked access you will have to destroy the seal before calling up the
menu and to short-circuit the two contacts on the circuit board [K2], using a jumper
(See chap. Fehler! Verweisquelle konnte nicht gefunden werden.).

Attention:
After destruction of the seal the weighing system must be re-verified by an
authorised agency and a new verification wire/seal mark fitted before it can be
reused for applications subject to verification.

Call up menu:

 Switch-on balance and during the selftest press .

 Press , , subsequently, the first menu block „PO

CHK“ will be displayed.

 Press repeatedly until „P2 mode“ will be displayed.
 Operate the adjustment switch (models KFB-TM).

 Press and use to select the weighing scales type.

Single-range balance

Dual range balance
Multi-interval balance





KFB-TM/KFN-TM-SH-e-1410 - 26 -

Example single range scales (d = 10 g, max. 30 kg)

 Confirm selected weighing scales type by pressing ; the first

menu item „COUNT“ will be shown.

1. Display internal resolution

 Press , the internal resolution will be shown.

 Return to menu by .

 Press to select the next menu item.

2. Position decimal point

 Press , the currently set position of the decimal dot is

displayed.

 Press to select the desired setting.

Options 0, 0.0, 0.00, 0.000, 0.0000.

Confirm input by .

 Press to select the next menu item.

3. Readability

 Press and current setting will be displayed.

Select desired setting by .
Options 1, 2, 5, 10, 20, 50.

Confirm entry by .

 Press to select the next menu item.

- 27 - KFB-TM/KFN-TM-SH-e-1410

4. Capacity

 Press , the current setting will be displayed.

Using the navigation buttons (see chap. 2.1.1) select the desired
setting, the active digit is flashing.

Confirm input by .

 Press to select the next menu item.

5. Adjustment / linearization
Adjustment or linearization is required after entering configuration
data.
For carrying out adjustment see chap. Fehler! Verweisquelle

konnte nicht gefunden werden./step 6 or chap. Fehler!
Verweisquelle konnte nicht gefunden werden. for linearisation

Example dual range scales (d = 2 / 5 g, max. 6 / 15 kg)

 Confirm selected weighing scales type by ; the first menu

item „COUNT“ will be shown.

1. Display internal resolution

 Press , the internal resolution will be shown.

 Return to menu by .

 Press to select the next menu item.

2. Position decimal point

 Press , the currently set position of the decimal dot is

displayed.

 Use to select the desired setting.

Options 0, 0.0, 0.00, 0.000, 0.0000.

Confirm input by .

KFB-TM/KFN-TM-SH-e-1410 - 28 -

 Press to select the next menu item.

3. Readability

 Press , the display used to enter readability/verification value

for first weighing range will appear.

 Press , the current setting will be displayed.

 Select desired setting with and acknowledge by .

 Press to enter the next menu item for readability/verification

value for second weighing range.

 Press and current setting will be displayed.

 Select desired setting with and acknowledge by .

 Press , the unit will return to the menu

 Press to select the next menu item.

- 29 - KFB-TM/KFN-TM-SH-e-1410

4. Capacity

 Press and the display for entering the capacity for the first

weighing range will appear.

 Press and current setting will be displayed.

 Select desired setting with and acknowledge by .

 Press to select the next menu item used to enter the

capacity for the second weighing range.

 Press and current setting will be displayed.

 Select desired setting with and acknowledge by .

 Press , the unit will return to the menu

 Use toselect next menu item.

5. Adjustment / linearization
Adjustment or linearization is required after entering configuration
data.
For carrying out adjustment see chap. Fehler! Verweisquelle

konnte nicht gefunden werden./step 6 or chap. Fehler!
Verweisquelle konnte nicht gefunden werden. for linearisation

 Acknowledge using , the current setting is displayed.
 Acknowledge by , select desired setting with

= Adjustment

= Linearisation



KFB-TM/KFN-TM-SH-e-1410 - 30 -

Non verifiable weighing systems

(contacts of circuit board [K1] not short-circuited )

+ For menu overview see chap. 5.1.

Call up menu

 Switch-on balance and during the selftest press .

 Press , , subsequently , the first menu block „PO

CHK“ will be displayed.

 Press repeatedly until „CAL“ will be displayed.

 Press , the first menu item „COUNT“ will be displayed.

Navigation in the menu

 With help of , the individual menu items can be selected

one after the other.

 Confirm selected menu item by pressing . The current

setting will be displayed.

 To change to the available settings, press the navigations keys as

described in chap. 2.1.1.

 Either save by pressing or cancel by pressing .
 Press repeatedly to exit menu.

Parameter selection

1. Display internal resolution

 Press , the internal resolution will be shown.

 Return to menu by .

 Use to select another menu item.

2. Position decimal point

- 31 - KFB-TM/KFN-TM-SH-e-1410

 Press , the currently set position of the decimal dot is

displayed.

To make changes using the navigation keys (See chap. 2.1.1),
select the desired setting. Options 0, 0.0, 0.00, 0.000, 0.0000.

Confirm input by .

 Use to select another menu item.

3. Weighing scales type, capacity and readability

 Press and current setting will be displayed.

 Select desired setting by .

„off“ Single-range balance
„on“ Dual range balance

 Press to confirm, the display for entering readability (for dual

range scales for the first weighing range) appears.

 Press , the current setting will be displayed.

 Select desired setting with and acknowledge by .

 Press , the display for entering capacity will appear (at dual

range balance for the first range).

 Press , the current setting will be shown (such as max. =

2000kg).

 Using the navigation buttons (see chap. 2.1.1) select the desired

setting, the active digit is flashing.

 Acknowledge with .

In a single-range balance the entry of capacity / readability is

KFB-TM/KFN-TM-SH-e-1410 - 32 -

finished.

either in single-range balance

 Press , the unit will return to the menu Press to call up

next menu item „CAL“.

or

In a dual range balance enter readability/verification value and
capacity of the second weighing range.

 Press , the display for entering the capacity of the second

weighing range will appear.

 Press , the current setting will be displayed.
 Using the navigation buttons (see chap. 2.1.1) select the desired

setting, the active digit is flashing.

 Confirm input by .

 Press , the display for entering the readability of the second

weighing range will appear.

 Press , the current setting will be displayed.

 Select desired setting with and acknowledge by .

 Press , the unit will return to the menu

 Press to call next menu item.

4. Adjustment or linearisation
Adjustment or linearisation is required after entering configuration
data.
For carrying out adjustment see chap. Fehler! Verweisquelle

konnte nicht gefunden werden./step 4 or chap. Fehler!
Verweisquelle konnte nicht gefunden werden. for linearisation

 Acknowledge using , the current setting is displayed.
 Press to confirm, press to select the desired setting



- 33 - KFB-TM/KFN-TM-SH-e-1410

noLin = Adjustment
LineAr = Linearisation

10 MAINTENENCE

WARNING

DISCONNECT ALL POWER TO THIS UNIT BEFORE
INSTALLING, CLEANING, OR SERVICING. FAILURE
TO DO SO COULD RESULT IN BODILY HARM OR
DAMAGE THE UNIT.

CAUTION

 Permit only qualified persons to service the instrument
 Before connecting or disconnecting any components, remove the power.
 Failure to observe these precautions bodily harm or damage to or

destruction of the equipment.

KFB-TM/KFN-TM-SH-e-1410 - 34 -

10.1 General

If the scale does not operate properly, find out the problem as possible.
Determine whether the problem is constant or alternate. Be aware that problems can be

caused by mechanical or electrical influences.

Check the following.

 Water
 Corrosive materials
 Vibrations or temperature or wind
 Physical damage

Check the indicator cables for damage, and check all connections and connecters for any

loose contact or incorrect connection

10.2 Error Codes

Indicator’s error message’s following lists

ERROR
CODES

DESCRIPTION

RESOLUTION

-----

Over load

Weight on the scale exceeds calibrated
capacity. Decrease load on the scale.

If the problem persists re calibrate the scale

Err 4

Scale not zeroed at
power up

Auto Zero on power up is exceeded due to
switching on.(4%max)

Zero the scale or remove the weight. Re
calibrate the scale.

Err 6

A/D out of range

The values of the A/D converter are outside
from the normal range. Remove the weight
from the scale if overloaded and make sure
the pan is attached.

Load cell or the electronics may be faulty.

9.3. Determine the Problem

- 35 - KFB-TM/KFN-TM-SH-e-1410

Determine whether the problem is in the indicator or the platform

 Remove power from the system, and disconnect the indicator from the platform
 Connect the indicator to a load cell simulator
 Reapply power and test the indicator
 If problem goes away, its source is probably in the platform. Check the wiring,

connecter, load cells and mechanical components of the platform.
If problem persists, its source is probably in the indicator. Check the indicator

voltages, connecters, cables and function programs.

10.3 Check the Load cell

 Remove power from the system, and disconnect the indicator from the platform
 Remove the load connecter from platform terminal.
 Check the moisture, or foreign material inside.
 Make sure all leads are connected and correctly. See the details of connections in the

Installation section.

 Check load cell for proper input and output resistances

Measuring Points

Resistance

+ Exc to –Exc (Input)

Minimum 350 ohms

+Sig to –Sig (Output)

347 ~ 353 ohms

10.4 Check Indicator Voltages

If the problem is in the Indicator, use a multimeter to check the following voltages

AC Power

Check the AC power socket out put voltage.

 Voltage must be a -20% and +10% of the normal AC voltage.

Adaptor Voltage

Check the adaptor output cable connecter voltage

 Voltage must be minimum 9VDC and maximum 15VDC

KFB-TM/KFN-TM-SH-e-1410 - 36 -

PCB Input Voltage

Check the PCB input power connecter voltage

 Voltage must be minimum 9VDC in to the pin AD+

Check Battery Voltage and Charging Voltage

1. Check the Battery Voltage,

 Voltage must be minimum 6VDC. If below the 6VDC connect the adaptor for charging
 The battery voltage below the 5.5VDC, replace the battery and install new 6V/4Ah

battery.

2. Check the Battery Charging Voltage;

 Remove the battery connection terminals (Red and Black) from the battery.
 Connect the power and turn on the Indicator
 Voltage into the terminal minimum 6.5VDC

- 37 - KFB-TM/KFN-TM-SH-e-1410

10.5 Problems and Solutions

Problems

Possible cause

Common Solutions

Display is blank.
No self test

Mains power is turned
off. Power supply faulty
or not plugged. Internal
battery is not charged.
On/Off switch problem

Check power is getting inside the scale
and on/off switch is working.

Verify the voltages, which is on the
power labels.

Blank display after
self test

Pan not installed.
Unstable weight, load

cell damaged

Check the pans are installed correctly.
Try to turning on again.

OL or -------

Maximum capacity
exceeded. Load cell or
mechanics damaged.
Power supply faulty

Check the platform is installed
correctly. Try to turn on the scale
again. Do the calibration again

------- or NULL
displayed

Weight is on the platform
is below permissible limit.
Pan not installed
correctly.

Power supply faulty.
Load cell or mechanism

faulty

Check the platform is installed
correctly. Try to turn on the scale
again.

Do the calibration again

Display is unstable

Goods touching
somewhere. Air variation
or any vibrations.
Temperature changed .
Load cell or connections
faulty.

Power supply faulty

Check the scale is in acceptable
location.

Check the connecters and load cell.
Check the power supply and battery

Weight value
incorrect

Calibration error.
Platform of load cell

touching somewhere.
Wrong weighing unit

Use accurate weight for to do the
calibration

Check the pan and load cell is installed
proper and touching.

Check the parameter settings.

KFB-TM/KFN-TM-SH-e-1410 - 38 -

Check the load cell and connecters

Can not use full
capacity

Over load protection
stoppers or transport
locks are not removed.

Parameters are set
incorrectly.

AD problem.
Load cell or mechanism

damaged

Check the stoppers and locks under
the platform.

Check the weighing unit and parameter
settings.

Check the load cell.

Platform Corner
Weight different

Over load protection
stoppers or transport
locks are not removed.

Load cell or mechanism
damaged

Check the stoppers and locks under
the platform.

Use accurate weight for to do the
calibration

Check the load cell.

Battery not
charging

Mains voltage problem
Charging circuit problem
Battery Problem

Check the mains and adaptor.
Check the battery.
Check the charging circuit

- 39 - KFB-TM/KFN-TM-SH-e-1410

11 10. TROUBLE SHOOTING

11.1 No Power

Not good

Ok

Not good

Ok
Not good

Ok

Not good

Ok

Not good

Ok

START

Check power
switch connector

Check Battery
Voltage >6V

Check DU 4
pin 1 Out put 5V

CHK M/B DU3
pin 8 high level
when power on
and return to low

Replace power switch or
connecter

Recharge the battery or
Replace the battery

Check DU4 and around circuit

Check M/B DU3 and around
circuit

Check ST
(11.0592Mhz)

Check ST and around circuit

Check M/B DU1
and around circuit

KFB-TM/KFN-TM-SH-e-1410 - 40 -

No Display

Not good

Ok
Not good

Ok

Not good

Ok

Not good

Ok

Not good

START

Check LCD break
or loose contact

Check the cable
from main board
to display board

Check U3
pin 17 Out put 5V

Press key board
beeper

Replace LCD or connect
proper

Replace the cable or connect
proper

Replace IC power problem

Check U1 and around circuit

Check ST and around circuit

Check U3 and
LCD

- 41 - KFB-TM/KFN-TM-SH-e-1410

Battery not charging

Yes
No
Not good

Ok
Not good

Ok

Not good

Ok

START

Check Battery
Voltage < 5V

Check Adaptor out
put 9.5 V. with out
connect the scale

Check C1 +9 V

CHK M/B U5
pin2

Replace Battery

Check the adaptor or replace
adaptor.

Check BR, C1, C2 and
around circuit

Check M/B DU5 and around
circuit

Check M/B D1,
R1 and around
circuit

KFB-TM/KFN-TM-SH-e-1410 - 42 -

11.2 Not Weighing

Yes Yes

Ok

Not good

Ok

Not good

Not Good

START

Check can show
internal counts

Check M/B AU1 pin
15: 5V

Add load on pan,

CHK output between

M/B AU1 pin1 and pin2

signal change (mV)

Check load cell
and around
circuit

Do calibration

Check the load cell and input
circuit

Check M/B AU1 and around
circuit

Add load on the
pan, check the
counts increase

Check power
circuit

- 43 - KFB-TM/KFN-TM-SH-e-1410

11.3 Unstable

Yes

No
Yes

START

Check after warm
up

Check load cell
and bracket
touching
something

Humidity

Sole the touching problem

Check M/B AU1
and around circuit

KFB-TM/KFN-TM-SH-e-1410 - 44 -

12 11. CIRCUIT DIAGRAM

Power

Display

- 45 - KFB-TM/KFN-TM-SH-e-1410

CPU

KFB-TM/KFN-TM-SH-e-1410 - 46 -

- 47 - KFB-TM/KFN-TM-SH-e-1410

KFB-TM/KFN-TM-SH-e-1410 - 48 -

13 DRAWING

13.1 Drawing KFB-TM

- 49 - KFB-TM/KFN-TM-SH-e-1410

13.2 Parts List

No

Parts Name

Qty

Spec

1

Key Panel

1 2

Display Protection Plate

1

3

Front Cover

1

4

Main PCBA

1 5

Insulation Washer

9

6

Self Thread Screw

10

3x10

7

Washer

4

8

Battery bar

2 9

Battery

1

6V/1.2AH

10

Self Thread Screw

2

M3

11

Nut 3 M3, Hexagon

12

RS-232 port

1

13

D Connecter

1 14

Star (+) Screw

1

3Mx20

15

Branch pipe

1 16

Main Serial board

1

17

Interface Module

1

18

Back Cover

1

19

Air Connecter

1 20

Star (+) Screw

7

M4x16

KFB-TM/KFN-TM-SH-e-1410 - 50 -

13.3 Drawing KFN-TM

- 51 - KFB-TM/KFN-TM-SH-e-1410

13.4 Parts List

No

Parts

Qty

Spec

1

Key Panel

1 2

Front Cover

1

3

Display Protection Plate

1

4

Nut 6 M3*6

5

Main PCBA

1

6

Washer

6

8x3.1x1.5

7

Star (+) Self Thread screw

6

M3x8

8

Water Proof Rubber Bar

1 9

Star (+) Screw

2

M4x10

10

Washer

2

M4

11

Battery Clamp

1 12

Washer

6

M4

13

Star (+) Big head Screw

6

M4x12

14

Bracket

1

15

Bracket Screw

2 16

Water Proof Adaptor jack

1

17

Interface Module

1

18

Air connecter

1

5Pin

19

Plug

1 20

Rubber Spacer

3

21

Air Connecter

1

7Pin

22

Back Cover

1 23

Air Connecter Water Proof Nut

1

24

Battery

1

6V/4Ah

25

Nut 1 M3x6

26

Main Serial board

1

KFB-TM/KFN-TM-SH-e-1410 - 52 -

27

Spacer

1

28

Star (+) Screw

1

3Mx20

29

Micro Switch Cap

7