KERN MCN-M User manual

KERN & Sohn GmbH
Ziegelei 1
D-72336 Balingen
E-Mail: info@kern-
sohn.com
Tel: +49-[0]7433-
9933-0
Fax: +49-[0]7433-9933-
149
Internet: www.kern-
sohn.com
Service Manual
Medical Chair scale
KERN MCN-M
Type TMCN 200K-1M-A
Version 2.0
05/2022
GB
MCN-M-SH-e-2220

2 MCN-M-SH-e-2220
GB
KERN MCN-M
Version 1.0 –05/2022
Servicemanual
Table of contents
1Basic Information........................................................................................... 3
2Introduction.................................................................................................... 3
3Appliance overview ....................................................................................... 4
3.1 Feature overview........................................................................................................................ 7
3.2 Keyboard overview..................................................................................................................... 8
3.3 Installing the chair scales ........................................................................................................... 9
3.4 Levelling ................................................................................................................................... 10
3.5 Mains connection...................................................................................................................... 12
3.6 Safety cable.............................................................................................................................. 12
3.7 Rechargeable battery operation with an optional battery power pack ..................................... 13
3.8 Battery operation...................................................................................................................... 14
3.9 Insert batteries.......................................................................................................................... 15
3.10 Initial Commissioning................................................................................................................ 16
4Calibration and sealing information........................................................... 17
4.1 General introduction:................................................................................................................ 17
4.2 Verification notes:..................................................................................................................... 17
4.3 Position adjustment switch and seals:...................................................................................... 18
4.4 Verification validity period (current status in G)........................................................................ 18
5Service Menu................................................................................................ 19
5.1 Software identification .............................................................................................................. 20
5.2 Adjustment................................................................................................................................ 20
5.3 Adjustment procedure .............................................................................................................. 21
6Maintenance................................................................................................. 22
6.1 Service, maintenance............................................................................................................... 22
6.2 Error Codes .............................................................................................................................. 22
6.3 Check the Load cell.................................................................................................................. 23
6.4 Checking the different Voltages ............................................................................................... 23
6.5 Trouble Shooting ...................................................................................................................... 24
7Exchange of components ........................................................................... 25
7.1 Spare parts list.......................................................................................................................... 25
7.2 Opening the device................................................................................................................... 25
7.3 Exchange of components......................................................................................................... 26
7.4 Replacement of the main board ............................................................................................... 26
8Technical drawings...................................................................................... 27
8.1 Exploded view chair construction............................................................................................. 27
8.2 Exploded view indicator............................................................................................................ 29
8.3 TKMG/TKMH Wiring Diagram.................................................................................................. 31
8.4 TKMG/TKMH Functional Block Diagram.................................................................................. 32
8.5 TKMG/TKMH Schematic Diagram ........................................................................................... 33

MCN-M-SH-e-2220 3
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 must 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.
The operation and configuration of each scale is described in the accompanying
manual of the scale. Any safety information in respect for verification are also
described in the accompanying manual
2 Introduction
This service manual covers the MCN chair scale 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.

4 MCN-M-SH-e-2220
3 Appliance overview
1. Seat pan
2. Bubble level
3. Display Unit
4. Manipulations
5. Parking brake
6. Adjustment switch
7. Terminal power supply unit
8. Connection cable "Display - Chair"
9. Battery compartment
10. KUP interface (Kern Universal Port)

MCN-M-SH-e-2220 5
Details:
Parking brake open
Parking brake closed
Footrest and adjustment foot
Accessory bag

6 MCN-M-SH-e-2220
Folding arm rests

MCN-M-SH-e-2220 7
3.1 Feature overview
•Large LCD, 6-digit H=25mm, VA=100x40mm, no backlight
•Stable, zero, battery level, gloss/net weight indications
•Weighing unit: kg only
•6 buttons operated
•Tare up to Max
•Pre-Tare function, with 4 memories
•BMI function
•Display Hold function
•Print function
•Application menu
•Setup menu
•Service menu
•Kern Communication Protocol (KCP)
•Kern Universal Port (KUP) interface, VGA-15 female connector
•Built-in WiFi interface
•Optional internal Memory / Real Time Clock module
•Optional external RS-232 interface through KUP
•Optional external USB device interface through KUP
•Optional external Bluetooth BLE interface through KUP
•Multi-Plug (EU/UK) Power adaptor, 6V 1A
•Optional Alkaline Batteries, 6xAA size
•Optional rechargeable battery pack, Li-ion 3.7V 3700mAH

8 MCN-M-SH-e-2220
3.2 Keyboard overview
Button
Designation
Function
ON/OFF button
Turn on/off
HOLD button
Hold function/Calculation of a stable weight value
In menu:
•Select menu items
For numeric entry:
•Lowering numeric value
BMI button
Calculation of the Body Mass Index
In menu:
•Return to weighing mode
PRINT button
Data transfer via interface
In menu:
•Select menu items
For numeric entry:
•Increase numerical value
Function key
Function quick key
Quick call-up of a function stored before
Zeroing key
Weighing scale will be reset to „0.0“
In menu:
•Confirm selection
For numeric entry:
•Change decimal digit
•Confirm entry
TARE key
Tare balance

MCN-M-SH-e-2220 9
3.3 Installing the chair scales
Place scales on an even surface.
Check if the air bubble of the level is within the prescribed circle.
If the air bubble of the bubble level is not in the required circle, level the
balance using the adjustment feet as specified.
Check levelling regularly.

10 MCN-M-SH-e-2220
3.4 Levelling
•Levelling is restricted to specialist staff possessing well acquainted
with the workings of weighing scales.
Place scales on an even surface.
Lock brakes
Turn the wheel (1) until the air bubble of the bubble level is in the black
circle
Turn the counter nuts (2) right to the top

MCN-M-SH-e-2220 11
Gap width must not exceed 15 mm!
Use the adjustment feet to fix the chair at the front wheel.

12 MCN-M-SH-e-2220
3.5 Mains connection
Terminal power supply unit
Power is supplied via the external mains adapter. The specified voltage must
correspond to the local voltage.
Only approved genuine KERN power supply units may be used in compliance with
Directive EN 60601-1.
The small sticker attached to the side of the display unit indicates the power port.
3.6 Safety cable
Safety cable for strain relief of the mains cable.
Application:
Installation for strain relief between mains cable (plug-in power supply unit) and
display unit.

MCN-M-SH-e-2220 13
3.7 Rechargeable battery operation with an optional battery power pack
Open the battery compartment cover (1) at the base of the display unit and insert the
rechargeable battery. Charge the battery for at least 12 hours before initial use.
The appearance of the symbol in the weight display indicates that the
rechargeable battery is almost exhausted. The weighing scale will remain ready for
operation for a few more minutes before switching off automatically in order to save
the rechargeable battery. Charge rechargeable battery.
Voltage has dropped below prescribed minimum
Rechargeable battery very low
Rechargeable battery completely recharged
•If the rechargeable battery is exhausted, „LobAt“ is
displayed. The rechargeable battery is charged via the
provided plug-in power supply unit (charging time 12 h for
a complete charging).
•If the balance is not used for a longer time, take out the
rechargeable battery and store it separately. Leaking liquid
could damage the balance.

14 MCN-M-SH-e-2220
3.8 Battery operation
As an alternative for the rechargeable battery operation, the balance offers also the
possibility to be operated with 6x AA-batteries.
Open the battery cover (1) at the lower side of the display unit and insert the batteries
according to the example shown below. Lock again the battery compartment cover. If
the batteries are exhausted, the symbol and „Lo bAt“ is displayed on the
balance; replace the batteries. To save the battery, the balance switches
automatically off.
+
Lo bAt
Capacity of batteries exhausted.
Capacity of batteries will soon be exhausted.
Batteries completely charged

MCN-M-SH-e-2220 15
3.9 Insert batteries
Remove the battery compartment cover
at the side of the display unit (1)
Remove the battery holder (2)
Insert the batteries into the battery
holder
Insert batteries with the battery holder
into the battery compartment and lock it
with battery compartment cover.
Insert batteries in the battery container
and lock them with battery compartment
cover.

16 MCN-M-SH-e-2220
3.10 Initial Commissioning
In order to obtain exact results with the electronic balances, the balance may only be
used after the operating temperature is reached. During this warming up time the
balance has to be connected to the power supply (mains, accumulator or battery) and
be switched on.
The accuracy of the balance depends on the local acceleration of gravity.
The value of gravity acceleration is shown on the type plate.

MCN-M-SH-e-2220 17
4 Calibration and sealing information
4.1 General introduction:
According to EU directive 2014/31/EU balances must be officially verified if they are
used as follows (legally controlled area):
a) For commercial transactions if the price of goods is determined by weighing.
b) For the production of medicines in pharmacies as well as for analyses in the
medical and pharmaceutical laboratory
c) For official purposes
d) For manufacturing final packages
e) Determination of mass in the practice of medicine that is, weighing patients for
reasons of medical supervision during medical surveillance, examination and
treatment
In cases of doubt, please contact your local trade in standard.
4.2 Verification notes:
An EU type approval exists for balances described in their technical data as verifiable.
If a balance is used where obligation to verify exists as described above, it must be
verified and re-verified at regular intervals.
Re-verification of a balance is carried out according to the respective national
regulations. For verification validity period.
The legal regulation of the country where the balance is used must be observed!
Verification of the balance is invalid without the seal.
The seal marks attached on balances with type approval point out that the
balance may only be opened and serviced by trained and authorised
specialist staff. If the seal mark is destroyed, verification loses its validity.
Please observe all national laws and legal regulations. In Germany a
re-verification will be necessary.
Balances with obligation to verify must be taken out of operation if:
•The weighing result of the balance is outside the error limit. Therefore,
in regular intervals load balance with known test weight (ca. 1/3 of the max.
load) and compare with displayed value.
•The reverification deadline has been exceeded.

18 MCN-M-SH-e-2220
4.3 Position adjustment switch and seals:
4.4 Verification validity period (current status in G)
Personal scales (including chair and wheelchair scales) in
hospitals
4 year
Personal scales, when not located in hospitals (for example,
doctor's offices and nursing homes)
unlimited
Baby weighing scales and mechanical birth weight scales
4 year
Bed scales
2 year
Scales in dialysis stations
unlimited
Rehab clinics and health authorities are treated as hospitals.
(4 years of verification validity)
Not treated as hospitals (verification validity not limited) are dialysis stations, nursing
homes and doctor’s surgeries.
(Details derived from: „Information by the verification authority, weighing scales
applied in medical use“)

MCN-M-SH-e-2220 19
5 Service Menu
Press the verification button to enter Service Menu (may need to break the seal)
Press ➔ button to select / confirm / shift right
Press  button to go back / exit / shift left
Press  button to scroll down / decrease digit value
Press  button to scroll up / increase digit value x10
x10
turn ON/OFF X10 mode (for verified=on only)
ADJUST
adjustment
cal
adjustment function (as in User Menu)
calext
adjustment at predefined weight: zero, put ld, wait…
CALEUD
enter adjustment weight (SI unit only: g/kg), update predefined weight then
perform adjustment
GRAADJ
set gravity of adjustment location
GRAUSE
set gravity of use location
Linear
Linearization
3point
3 points
5point
5 points
zero
zero calibration
creep
creep compensation (at load)
params
scale parameters
VERIFD
Legal verification: ON/OFF
RNGTYP
Range type: 1 range, multi-range, multi-interval
NUMRNG
Number of ranges: 2
RANGE1
Range #1
max
Capacity in base unit
d
divison in base unit
E
e = number of d (only for single range and last digit = 1)
RANGE2
Range #2
max
Capacity in base unit
OVeRLD
overload counter
mem
view counter
ovrer
erase overload count
Memory
1st id
ID of starting memory
init
Initialize memory
record
number of records in memory
info
information querry
SERIAL
Serial number
VER
Software version B 1.2.16
vera
Software version approved a 1.0.0
advalu
show A/D value
reset
reset
all
reset all

20 MCN-M-SH-e-2220
5.1 Software identification
For the control purposes, the version management of the software in KMG/KMH
medical indicator which is used for MPN-, MWN- & MCN-series is divided into two
parts:
- Part I: Weighing system version
Program parts and data that form the software subject to legal control.
- Part II: Application version
Program parts and data that form the software not subject to legal control.
To check the software version, press any button during the display check at start up.
- Software version for legally relevant software identification: Ax.x.xx
- Software version for non-legally relevant software identification: Bx.x.xx
Software history:
- 2022-05: A1.0.00 B1.3.05 (initial release version)
5.2 Adjustment
As the acceleration value due to gravity is not the same at every location on earth,
each display unit with connected weighing plate 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 weighing system 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 display unit periodically in weighing operation.
•Prepare the required adjustment weight. The adjustment weight to be
applied depends on the capacity of a weighing scale.
Carry out adjustment as closely as possible to admissible maximum
load of weighing scale. Information about test weights can be retrieved
on the KERN website (http://www.kern-sohn.com).
•Observe stable environmental conditions. For warm-up time required for
stabilisation MCN-M Instruction manual.
Access to service menu is locked in verified balances.
To disable the access lock, destroy the seal and actuate the adjustment
switch.
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.