Kendro Multifuge 3 S-R User manual

Multifuge®3 S-R/3 L-R, Legend®RT
120V 50/60 Hz
SERVICE MANUAL P/N 12004376

Edition: 03 TABLE OF CONTENTS
22.11.01 AH Page: 0 - 2Legend RT
Multifuge 3S-R / 3L-R
TABLE OF CONTENTS
Section Title Doc.- No. Page
1OPERATING INSTRUCTIONS
2SERVICE
2.1 Servicing Schedule 2-1/2
2.2 Trouble Shooting 2-3
2.3 Error Code 2-4/7
2.4 Test Points 2-8
2.5 Imbalance Behavior 2-9
2.6 Cleaning of Instrument Parts 2-9
2.7 Electrical Safety Check 2-10
3FUNCTIONAL DESCRIPTION
3.1 Block Functions 3-1
3.2 Main Board Functions 3-1/2
3.3 Key and Indication Board - Easycontrol 3-3
Key and Indication Board - Quickcontrol 3-4
3.4 Speed Detection Board 3-5
3.5 Rotor Indication 3-5
3.6 Imbalance Detection 3-5
3.7 Lid Lock System 3-5
3.8 Cooling Plant 3-5
4DIAGRAMS
4.1 Block Diagram 4-1
4.2 Wiring Diagrams 4-2/3
4.3 Wiring Connection Diagrams 4-4/6
4.4 Main Board, Component Plan 4-7/14
4.5 Display Board, “Easycontrol” Keypad version,
Component Plan 4-15
Display Board, “Quickcontrol” Rotary switch
version, Component Plan 4-16
4.6 Speed detection, Component Plan 4-17
4.7 Sensor Board, Component Plan 4-18
4.8 Rotor Detection Board, Component Plan 4-19/20
4.9 Cooling Plant 4-21
5DISASSEMBLY OF INSTRUMENT PARTS
5.1 Housing / Casing Parts 5-1/2
5.2 Electrical Components 5-2/3
5.3 Drive Components 5-3/4
5.4 Cooling Plant 5-4
6SPARE PART FIGURES AND LISTS
6.1 Spare Part Figures 6-1/9
6.2 Spare Part Lists
7TECHNICAL BULLETINS
8Preventive maintenance checklist
Calibration Certificate

Service
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Multifuge 3S-R/3L-R
Service
2.1 Servicing Schedule (yearly procedure recommended)
2.1.1 Maintenance Routine without Dismantling the Centrifuge
2.1.1.1 Electrical Installation and Safety
• Switch OFF the centrifuge and disconnect the unit from power, check voltage supply and mains
fusing (16 Amps, slow blow characteristic)
• Check condition of plug and wall socket - replace defective parts (customer’s responsibility)
• Check cord condition and fixing / connection - replace or refit it
• Check condition of instrument socket and replace it in case of bad contacts
2.1.1.2 Location and Mechanical Installation
• Check the base (ground, table, lorry with lockable wheels etc.) for resonance-free and stable
conditions
• Check for a well ventilated place and sufficient distances to walls or adjacent equipment, without
exposition to direct sunlight
• Check the leveling of the centrifuge drive with use of a spirit level
2.1.1.3 Lid Tumbler Mechanism and Safety Device
• Connect the centrifuge to power and switch ON
• Check for correct automatic lid closing and self-acting lid opening - if in disorder, readjust lid,
swivel hinges, and/or locking devices
• Check the rubber gasket for lid’s and bolt’s sealing and replace, if damaged
• For checking the electronically safety circuit: start the centrifuge, let it shortly run and stop it, the
lid must not be unlocked by the microprocessor as long as the speed is more than 60 rpm - if
safety circuit is out of function, replace main board
2.1.1.4 Cleanliness of Spin Chamber and Motor Casing
• Open the lid and remove the rotor (for loosening turn the T-handle Allen key (5mm) in arrow
direction - see rim of rotor chamber)
• Clean the spin chamber with a dry and absorbent cloth (remove all dust and moisture - see also
section for Cleaning)
• Check the cleanliness of the motor flange and take care of the annular slot around the motor shaft:
penetrating fluids can damage the upper spindle bearing or electronics, remove fluids with an
injector and/or absorbent paper
2.1.1.5 Rotor and Accessories Condition and Sealing, bellows
• Check the condition of rotors and accessory parts (especially all supporting or stressed partitions):
the rotor and/or accessory parts must not be used any longer, if there are visible traces of
mechanical damage or rust
• Check the condition of rotor and/or accessory sealing and replace them in case of malfunction
• Bellows of gas lid stays have to be greased upside down with glycerin (part no. 70902649) once a
year.
2.1.1.6 Rotor Fixing and Drive Spindle
• Check the perfect condition of the collet chuck and replace it in case of malfunction (thread is worn
out, horizontal grooves etc.)
• Check the condition of the drive cone: the centrifuge must not be used any longer, if the drive
cone is damaged (e.g. bend or it’s bearings are worn out)

Service
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Multifuge 3S-R/3L-R
2.1.1.7 Temperature Level (not at every unit)
• Check the wire gauze (behind the air inlet slots) left and right side for free ventilation, insufficient
air flow will lead to an inadmissible temperature rise of compressor, motor and electronic parts
2.1.1.8 Imbalance Behavior
• Install available and empty rotors and check the imbalance behaviour with rotor dependant cut off
and run through weights (see 2.5) and replace worn out motor rubber mounts, faulty main board or
sensor board
2.1.2 Maintenance Routine after Dismantling the Centrifuge Casing
2.1.2.1 Motor Supporting Elements
• Check the supporting and damping elements of the drive motor and replace them in case of
increased rubber abrasion or abundance of imbalance but at least every 3 years
2.1.2.2 Braking Circuit
• Check the function of the braking circuit (warming up of brake resistor, even and noiseless brake
effect) and replace defective parts in case of malfunction
2.1.2.3 Lead and Screwing Connections
• Check the terminal and plug connections of all leads and on all boards and electrical components,
tighten all loosen screwing connections, refit or replace defective parts
• Check the wedged connections of the board, mechanical and electrical components and re-tighten
them if necessary (use screw locking lacquer for motor mounts and lid lock assembly)
2.1.2.4 Protection Earth Core and Grounding Connections
• Check the protection earth core for continuity and all grounding plug connectors (see also 2.7
Electrical Safety Check)
• Check isolation resistance and accessible current (see 2.7)

Service
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Multifuge 3S-R/3L-R
2.2 Trouble Shooting
Error
Indication Error Cause Possible Error Source Corrective Procedure
Mains switch with
integrated fuse or
fuses on main board
Switch on again, disconnect electric.
components success., search for other
faults
Mains fuse or circuit
breaker failed
Check fuse or circuit breaker and replace o
r
switch on again
No mains
voltage supply
Faulty mains cord or
instrument socket
Check instrument cord and socket, replace
defective parts
Faulty connection
from CPU to
indication board
C
heck connections on CPU, indication board
and connecting leads, replace defective
parts
No low voltage
supply for
indication board Faulty indication or
CPU board Replace main board completely
Displays
remain
dark
Interrupted
program
NV-RAM out of
socket or not
correctly placed
Insert the valid NV-RAM and push it
correctly into socket
Reduced voltage
supply (<10%)
Remedy the failure if the voltage drops
often, use a voltage stabilizer
All display
Elements
are shortly
illuminated
CPU program
reset may be
caused by EMI Bad or missing
ground connection
Check all ground connections and the
ground connection of all boards
Constant Interruption Parameter NV-RAM No or defective NV-RAM
Mechanics wear out of motor
rubber mount
Replace motor rubber mounts (at least
every three years)
Defective terminal
connection, faulty
lead or motor winding
Check voltage on motor terminal and
winding resistances -see test points on
main board
Drive
makes
noises -no
good
separation
result
Electrical
Faulty power electr. Replace main board
Locking drive is
not supplied
with voltage
24V supply
faulty relay K2
faulty driving circuit
Check voltage for drive motor
Check switch. after power ON
Replace the main board
No or defective NV-RAM
Latch motor Faulty motor winding Replace complete motor
Lid bolt is jamming Push lid centrally into lock and press the
key again
Lid cannot
be opened
by key at
standstill
Lid is not
correctly locked
Lid is deformed Re-adjust the lid centrally

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Multifuge 3S-R/3L-R
2.3 Error code
Error
Indication Error Cause Possible Error Source Corrective Procedure
„rotor“ in
speed
display
Wrong selection
of detected rotor
Inadmissible speed
or rcf value was pre-
selected
Press start again (within 15s), else wait for
rotor standstill, lid OPEN/CLOSE, set value,
start
Rotor not symmetri-
cally loaded
Open lid, check rotor loading, close lid again
and restart
Base is not sturdy
enough and comes
into vibrations
Change or reinforce the base (table, lorry with
lockable wheels, etc.)
Centrifuge drive is
not correctly leveled
Level the drive correctly by means of unit’s
feet
Rotor itself has
imbalance
Rotor must no longer be used, send back to
Kendro
Drive shaft or rotor
fixing is damaged Replace collet chuck or motor
Imbalance sensor Replace sensor board
“bAL“
message
appears in
speed
display
Imbalance run
Circuits of main
board Replace the main board
Lid was opened
manually during
run
Forbidden
intervention
emergency opening
device must only be
used at standstill
Close lid immediately, turn power OFF/ON,
press lid down for locking, press start key,
press stop to finish run
“Lid“
appears in
speed
display Protection circuit
(20V) interrupted
during run
Defective micro
switch or leads or
connectors to micro
switch are interrupted
Check leads and connectors to micro switch,
in case of a faulty micro switch, replace them
Loose plug
connectors Check plug X20
Interrupted leads to
micro switch Check leads to micro switch for continuity
„OPEn“
appears in
speed
display by
supposedly
closed lid
20V supply for
protection circuit
is interrupted at
standstill
Defective micro
switch Replace micro switch
“S-LID”
appears in
display
Sensor signal not
clear
Latch not in valid
position during power
on
Switch unit “off” and “on” again

Service
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Multifuge 3S-R/3L-R
Error Code
Error
Indication Error Cause Possible Error Source Corrective Procedure
„E-01“
message
System clock
pulse not stable
Hardware fault on
main board Change main board
„E-02“
message
program
sequence was
disturbed
Internal Software
problem Change CPU, replace main board
„E-03“
message Stack overflow Internal Software
problem No action in the field possible
„E-04“
message Stack underflow Internal Software
problem No action in the field possible
“E-05”
message
Reset by HW
watchdog timer Software problem No action in the field possible
“E-06”
message
Data lines to key
board disturbed Wiring display board Check wiring and connectors
“E-07”
message
Display board
doesn’t match to
main board
cooled/non-
cooled
Check software Replace NV RAM and CPU
“E-08”
message
Check sum error
E-PROM E-PROM failed Replace E-PROM
“E-09”
message
Check sum error
NV RAM NV RAM failed Replace NV RAM
“E-10”
message
NV RAM not
initialized
Initializing of NV-RAM
is not valid
check NV-RAM and socket, insert the correct
NV-RAM
“E-11”
message
NV RAM doesn’t
match E-PROM
Check versions of NV
RAM and E-PROM Replace NV RAM and E-PROM
“E-12”
message
Check sum error
NV RAM NV RAM failed Replace NV RAM
“E-13”
message
Check sum error
NV RAM NV RAM failed Replace NV RAM
Compressor didn’t
work
Check leads, terminals, start relay, capacitor,
compressor
„E-14“
message
chamber over
temperature:
display >50°C Faulty cooling cycle Exp. valve, refrigerant loss
„E-15“
message
Open temp.
sensor
Check sensor, control
circuits Replace sensor or main board
„E-16“
message
Short cut temp.
sensor
Check sensor, control
circuits Replace sensor or main board
a wrong rotor was
installed
wait for standstill, open the lid and install a
correct rotor
Mains voltage failure press stop key, wait for standstill and restart
„E-17“
message
wrong or faulty
rotor detection
Faulty detection
circuit replace the main board

Service
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Multifuge 3S-R/3L-R
Error Code
Error
Indication Error Cause Possible Error Source Corrective Procedure
„E-18“
message
Bucket code
not valid for this
rotor
Not valid
Wrong rotor installed Check rotor
„E-19“
message
Rotor code not
programmed Interference during
recognition Check rotor recognition board and wiring
„E-20“
message
rotor code not
valid See E-19
„E-21“
message
Recognition
disturbance wiring Check wiring
„E-22“
message
Speed signal
disturbance wiring Check wiring
„E-23“
message
Speed control
measuring
disturbance
2nd check was done
by rotor recognition
system
Check speed detection board
„E-24“
message
Latch not in top
position
Micro switch failed,
de-adjusted, latch
Check micro switch adjustment, if necessary
replace it
„E-25“
message
Time out latch
open
Hall sensor signal not
applied Check latch motor and PCB
„E-26“
message
Time out latch
close
Hall sensor signal not
applied Check latch motor and PCB
„E-27“
message
Signal given by
latch not valid
Wrong identified
signal after power
“on”
Check hall sensors
„E-28“
message
Wrong sense of
rotation
After replacement of
the motor- wires
mixed
Check wiring at terminal
„E-29“
message
Motor doesn’t
turn
PCB faulty, see E-21,
E-22
Change PCB, rotor recognition, speed
detection, fasten motor wiring at terminal
„E-30“
message
Control-voltage
interruption PCB failed Replace PCB
„E-31“
message
over-
temperature
motor >150°C
Hot motor, no air
circulation Check motor, check grill for dust
„E-32“
message
Over-
temperature
Electronic
Faulty main board Replace main board
„E-33“
message
High-pressure
Cooling system
Faulty high pressure
switch, blocked
system
Inspect cooling system

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Multifuge 3S-R/3L-R
Error Code
Error
Indication Error Cause Possible Error Source Corrective Procedure
„E-34“
message Over-voltage Brake resistor,
main board Check brake resistors, replace main board
„E-35“
message Over-current Main board Replace main board
„E-36“
message
NMI
interruption
Over voltage or over-
current Replace main board
„E-37“
message
Over-current
continuously Main board Replace main board
„E-38“
message
Current
measurement
disturbed
Analog signal >
hardware over current Replace main board
„E-39“
message
Speed control
check >n max.
Speed > calculated
speed
Check speed detection board, replace the
main board
„E-40“
message
Acceleration of
the unit is too
slow
Big imbalance
Motor or main board
faulty
Check rotor loading, motor and main board
„E-41“
message
Offset voltage
from the
imbalance
sensor is in a
inadmissible
area
Imbalance sensor
faulty
Wiring from the speed
detection board to the
main board is broken
Replace speed detection board
Check / replace the wiring

Service
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Multifuge 3S-R/3L-R
2.4 Test Points
Test Points Unit Value Conditions
Mains terminal
Board resistance
120V
50Ω
All given values are related on 120 V (+/- 10%) mains voltage for
board supply
Motor over-temp.
terminal
X20/B3,B4*
20V DC Voltage drop by one disconnected lead (error case) and linked
terminal XR
Over-press switch
terminal X20/P 20V DC Voltage drop by one disconnected lead (error case) and linked
terminal XO
Fans cooling plant
terminal XK
100 Ω
82 Ω
Switch OFF unit, fan resistance temperature 20°C
wire black to blue
wire brown to blue
Compressor
terminal XG
terminal box
–insulation value
6,5 A
1,6 Ω
4,8 Ω
> 10MΩ
Switch OFF unit, compressor temp. 20°C
Resistance of main coil + (starting relay 0.1Ω)
Resistance of auxiliary coil (joints 13 -> 14)
Resistance inter phase and motor casing
Speed detection
plug XW
(1 to 4)
(3 to 4)
speed
5V DC
4,4V
0V
n=f*30
Board with active filter circuit
Low voltage supply
Light barrier is passed through (slot position)
Light barrier is out (turn cone a little by hand)
When centrifuge is running
Imbalance sensor
plug XW
(1→4)
(2→4)
12V DC
a(t)
Low voltage supply of sensor board
Amplitude of lateral acceleration is rotor and speed dependent,
analyzed for n > 250 rpm
3 * 7A
Split core transformer with Flukemeter
maximum during acceleration
Motor current IM
cable (U,V,W) 3 * 5,2A
3 * 3,0A Rotor #6441, set speed = 3750min-1 , 560W
Motor winding
resistance 20°C –
insulation value
3x2,5Ω
> 10MΩ
Switch OFF unit, pull off motor plugs, measure inter
U -> V, V -> W, W -> U
Resistance inter each phase and motor casing
Brake resistor
terminal XD 60ΩSwitch OFF unit, 2 resistors parallel connected, resistance at
20°C
Rotor detection
plug XR
5V DC
0V DC
Per rotor revolution 2 different long
pulses are separated from 2 different
pulse pause lengths, this pulse mode is generated by 4 alternately
polarized magnets
Temp. measuring
plug XU
Chamber temperature 20°C (PT100: ≈108Ω)
Chamber temperature -10°C (PT100: ≈96Ω)
Chamber temperature 40°C (PT100: ≈116Ω)

Service
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Multifuge 3S-R/3L-R
2.5 Imbalance Behaviour
• Install in table available rotor(s) in unloaded condition
Rotor/Bucket Run through
weight
Cut off weight
75006445/75006441 20 grams 30 – 40 grams
• Insert rotor dependent cut-off weights and position them at angles of 90° to each other, the
centrifuge must stop 4 times indicating “bAL“ message - in case of false behaviour see trouble
shooting: no “bAL“ indication.
• Insert the admissible imbalance weights in the same manner, the centrifuge must run through 4
times to maximum rotor speed.
2.6 Cleaning of Instrument Parts
ATTENTION - WARNING!
The electrical and electronic components must not be cleaned with moist detergents!
For Cleaning the centrifuge housing or its accessories see Operating Instructions section 1
(maintenance and care).
• Electronic components
Clean dusty components carefully with a dry and soft brush and remove loose dust with a
vacuum cleaner.
• Fans
Scratch off carefully with a knife or similar tool the crusted dirt from the fans’ blades. Resulting
grooves or marks must be removed subsequently with a fine abrasive cloth. Loose dirt is to
remove with an absorbent cloth or vacuum cleaner.
• Vent holes
Remove dirt from the vent grid behind the front panel by using a brush and vacuum cleaner.
• Condensers of cooling plant (if available)
The louvers between the condensers’ heat air deflectors have to be vacuum cleaned. In case of
persistent dirt the unit must be carried to an appropriate place where the condensers can be
cleaned with compressed air from inside to outside. Bended heat air deflectors have to be
realigned correctly.

Service
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Multifuge 3S-R/3L-R
2.7 Electrical Safety Check
ATTENTION!
A final electrical safety check must be performed after each maintenance and/or repair!
• Resistance check of protective conductor
The measuring value of the resistance between the mains plug's grounding pin and the
grounding conductors of the motor, electronic chassis and the casing must not exceed 200 mΩ.
• Insulation resistance Check
Check also the insulation resistance between the poles of the mains plug and the grounding
conductor; the resistance value must be more than 2 MΩ.
• Accessible current measured to EN 61 010
The accessible current must not exceed 3.5 mAmps in single fault condition (interrupted
protection earth wire)! In accordance with the EN61010, IEC1010 and UL3101 such a fault
condition can be reproduced by the following measuring circuit.
500
Ω
±1%
L (N)
N (L)
PE
10k
Ω
±5%
0,022µF
±5%
V
AC
0,22µF
±5%
Steckergehäuse / plug-in casing
Spezifaktionen für Meßgerät
- TRMS, DC - 5kHz oder mehr
- Eingangswiderstand > 1M
- Toleranz 5% oder besser
- Crest Faktor 5 oder besser
Ω
Specifaction for the meter
- TRMS, DC - 5kHz or more
- Input resistance > 1M
- Tolerance 5% or better
- Crest Factor 5 or better
Ω
Körperstrom:
accessible current: I [mA] = U [mV] / 500:
U = 1750mV I = 3,5mA
max max
≡

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Multifuge 3S-R/3L-R
3Functional Description
3.1 Block Functions
The Multifuge 3L-R/3S-R, Legend RT is a refrigerated microprocessor controlled laboratory
tabletop centrifuge with noise reduced induction drive motor incorporating automatic rotor and
imbalance detection and self-closing door locking systems.
The unit is equipped with following boards and components (block diagram 4-1):
•Instrument socket for mains cable at the back
•Two poles mains switch
•Main board with microprocessor part and power electronics
•Key and indication board (program: EASYCONTROL II with temp. Display or QUICK-CONTROL
with adjusting knob)
•Sensor board with rotor detection sensors
•3 phase induction motor with integrated thermal over-temperature switch (C. O. 150°C)
•Speed detection and imbalance board with filter attached to the motor’s bottom by screws
•self-closing door locking system (mechanical bolt keeper, motor dis-locking)
•2 parallel brake resistors mounted on safety chamber (one with overtemp.sensor)
•axial-flow fan for power electronics, motor and chamber
3.2 Main Board Functions
The Main board is mounted at the housing behind the front panel. The components on main
board are arranged in following function blocks (see wiring diagram page 4-2 and 4-3).
•Noise filter in accordance with EN 55011 for motor and triac circuits
•Power pack for low voltage supply of microprocessor part and power electronics
•Triac driving circuits for compressor cut-in relay, for 2 independent fan wiring terminals and for
connection of a heater (special use)
•DC intermediate circuit for supply of frequency converter equipped with automatic loading and
voltage (brake) controlling circuits
•Power part inclusive physically separated driving stages
•Microprocessor part with CPU, E-PROM and NV RAM
•Driving component for self-closing lid lock device
•Interface component for serial RS232 (option)
•Exchangeable NV-Ram and E-PROM containing specific data of the unit
3.2.1 Power Pack
The power pack consists of 2 transformers, 2 rectifiers (single diode) and 2 voltage regulators, which
generates the following low voltage levels:
•U1 = 5V: by switched-mode regulator LM2575T-5.0, VDD, VCC
supplies all processors and its electronic components on main and indication board
•U2 = 24V: unregulated
is used for the driving of lid lock motor and relays K2, K3;
the reference potential is GND, VSS
•U3 = 20V: by 2nd transformer, rectifier diodes and fix voltage regulator 7820
serves for supply of driving of the power electronics via the protection circuit by closed lid
switches
reference potential: 0V CAUTION - MAINS POTENTIAL!

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Multifuge 3S-R/3L-R
Main Board Functions
3.2.2 Intermediate Circuit
The DC intermediate circuit serves as an energy store between the AC power input and the
transmitted motor performance. The intermediate circuit consists of a heat-sink-cooled bridge
rectifier and several reservoir capacitors which are softly charged across a power resistor R76 when
ever the unit is switched on. After the loading time (CPU initialization time) the power resistor is
linked by the relay contacts of K3. When switching the unit off, the DC voltage of the intermediate
circuit is discharged across a path of resistor R1, R2.
3.2.3 Brake Path
Electrical power is fed back into the intermediate circuit during motor deceleration (motor acts as
generator). This braking power is transformed into heat by two parallel connected resistors so that
the intermediate circuit voltage does not rise to an excessive level. The brake resistors are switched
into the intermediate circuit by a fast switching transistor (pulse-width modulation, synchronized by
the double mains frequency). This transistor is voltage dependent controlled by a self-acting stage
(closed loop).
3.2.4 Frequency Converter
The motor is 3-phased, provided with chopped direct voltage blocks (chopped frequency approx.
5kHz, amplitude is height of DC intermediate voltage). These blocks are variable in frequency and
pulse-width modulation, 120° out of phase. These 3 phases are controlled during acceleration,
running at set speed and deceleration (e.g. for small speed: low frequency and small pulse-width
length will be affected). The FC is protected against over current, over temperature and over-voltage.
3.2.5 Microcontroller (Central Processing Unit) Part
The software identification No's of the CPU and data storage’s (NV-RAM) ST24C32 are sequentially
displayed in speed and time fields:
Press program place no 2 during switch on
•CPU Operating panel: 526 P05
•Firmware: 528 200
•NV-RAM: 4468 105
The actually indicated version No.'s are displayed in the time field and will be upgraded if program or
data changes are necessary.
The control program (ROM) is integrated in the controller component. The most important operating
parameters (e.g. the maximum data for all rotors, the last operator settings, the basic values for
speed and temperature controlling, data of acceleration and deceleration curves as well as 4 data
sets of program places are stored in the non volatile (NV)-RAM.
When calling this routine the actual value of all centrifugation cycles (“CYL“) is also shown in the
display (as fourth No.) before the check routine for all program places puts an end to the initialization
time (approx. 18s).
The CPU co-operates with the E-PROM component via the 16 bit data bus and some control lines.
The CPU is an integrated circuit, generating all required output signals, monitoring and analyzing all
input signals.

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Multifuge 3S-R/3L-R
3.3 Key and Indication Board - Easycontrol
The key and indication board is mounted behind the operating panel. The connection to the main
board is done by a 4 pole cable by which the serial data transfer as well as the low voltage supply of
5V is verified. The 7-segment displays, the control LED’s and the operating keys are managed by an
own controller unit (first identification No. 591) in multiplex processing.
For the programming serves EASYCONTROL II (see Operating Instructions).
Functions of keys elements (Easycontrol)
Keys Designation Function(s)
S1 – S4 Program
place 1 to 4 Store or recall programs
S5 Arrow up Acceleration profile 1 to 9
S6 Arrow down Deceleration profile 1 to 9
S7 Speed arrow down Decrement the value of the set speed
S8 Speed arrow up Increment the value of the set speed
S9 Bucket Setting of the rotor / bucket number
S10 At the same time Switching between rpm and rcf display
S11 Time arrow down Decrement the value of the set time
S12 Time arrow down Increment the value of the set time
S13 Temp. Arrow down Decrement the value of the set temperature
S14 Temp. Arrow up Increment the value of the set temperature
S15 Frost Pre cooling
S16 Double arrow Quick run – hold button pushed
S17 Lid symbol Open the lid
S18 Arrow right Normal start of the centrifugation
S19 Red square Manual stop of a run
Functions of Indicating Elements (Easycontrol)
Indicat. Designation Function(s)
H1 Buzzer Audio signal
H2 Accel. curve digit Display defined acceleration curves 1 to 9
H3 Decel. curve digit Display defined deceleration curves 1 to 9
H4-H7,
H12 Speed range
Speed in rpm (rounded to full 10 rpms)
Rotor not yet detected (xxx „.“)
rcf-value (xg) or not yet possible to calculate „-----“
Identifications no.’s of controller and NV-RAMs,
Lid open condition („OPEn")
Centrifuge run is terminated („End")
Error messages („Lid“, „E-xx“, „bAL“, „rotor“)
H13-H15 Time range
Centrifugal time in h.min (count down process)
Count up process (hld) in h.min (count up process)
Actual version number („xx“)
H16,H17 Temperature range Sample temperature in °C±2K when pre-cooling or
pre-heating process is terminated
H18 Allocation LED For speed indication
H22 Allocation LED For rcf indication
H19,20,
24,25 Rotation Rotor spinning

Edition: 03 Servicing Schedule
13.03.01/he Page: 3 - 4Legend RT
Multifuge 3S-R/3L-R
Key and Indication Board - Quickcontrol
The key and indication board is mounted behind the operating panel. The connection to the main
board is done by a 4 pole cable by which the serial data transfer as well as the low voltage supply of
5V is verified. The 7-segment displays, the control LED’s and the operating keys are managed by an
own controller unit (first identification No. 591) in multiplex processing.
For the programming serves Knob control system Quickcontrol (see Operating Instructions)
Functions of keys elements (Quickcontrol)
Keys Designation Function(s)
S1 Adjusting knob Set point temperature
S2 Adjusting knob Set point time
S3 Adjusting knob Set point speed
S6 Arrow up Deceleration profile 1 to 3
S9 Bucket Setting of the rotor / bucket number
S10 At the same time Switching between rpm and rcf display
S16 Double arrow Quick run – hold button pushed
S17 Lid symbol Open the lid
S18 Arrow right Normal start of the centrifugation
S19 Red square Manual stop of a run
Functions of Indicating Elements (Quickcontrol)
Indicat. Designation Function(s)
H1 Buzzer Audio signal
H3 Decel. curve digit Display defined deceleration curves 1 to 3
H4-H7,
H12 Speed range
Speed in rpm (rounded to full 10 rpms)
Rotor not yet detected (xxx „.“)
rcf-value (xg) or not yet possible to calculate „-----“
Identifications no.’s of controller and NV-RAMs,
Lid open condition („OPEn")
Centrifuge run is terminated („End")
Error messages („Lid“, „E-xx“, „bAL“, „rotor“)
H13-H15 Time range
Centrifugal time in h.min (count down process)
Count up process (hld) in h.min (count up process)
Actual version number („xx“)
H16,H17 Temperature range Sample temperature in °C±2K when pre-cooling or
pre-heating process is terminated
H18 Allocation LED For speed indication
H22 Allocation LED For rcf indication

Edition: 03 Servicing Schedule
13.03.01/he Page: 3 - 5Legend RT
Multifuge 3S-R/3L-R
3.4 Speed Detection Board
On a small board, which is attached underneath the motor, the circuits for speed detection and signal
shaping are arranged. The motor speed is optically detected by an infra-red light barrier. The motor
axle has a hole at the same level as the light barrier. This effects that the light beam will be
interrupted twice during one motor revolution. A following pulse shaping stage on board forms
square-topped pulses which are led via XW1 to the main board. The speed pulses are counted by
the CPU to display the exact motor speed.
3.5 Rotor Indication
In the rotor’s bottom 4 magnets are forced, being alternately arranged in polarity and positioned to
each other to different distances on a constant circular ring (segment steps of 20°).
A Hall sensor is exactly fixed below to the sensor board. The magnets are switching a flip-flop stage
by which different pulse lengths and pulse intermissions are generated during one rotor rotation. By
this signal the CPU is able to detect up to 65 different rotors and the correct direction of rotation, too.
3.6 Imbalance Detection
On the speed detection board a piezoelectric acceleration detector is additional fixed. Dependent of
the rotor imbalance this sensor generates an analogous voltage signal which is led via a following
band-pass filter to plug connection XW1/2 to main board, where it is analysed by CPU. When the
CPU) has identified the installed rotor type, the speed dependent imbalance limitation curve from E-
PROM The analogue imbalance signal is filtered, converted into digital form and continuously
comperated with this specific limitation curve. If the actual imbalance signal will rise at any speed
beyond the limit, the error signal for imbalance load “bAL“ will be displayed and the unit slows down.
3.7 Lid lock system
The latch is directly controlled by CPU via a PWM motor driver. If all necessary signals are existing
which allow an opening the motor is fired with a pulsed voltage of 24 VDC. For additional safety the
relay K2 will be activated if the speed is below 120 rpm controlled by triggered mono-flops.
3.8 Cooling plant
The Multifuge 3SR/LR, Legend RT is equipped with a high-grade cooling plant, to meet it’s
requirements of driving power and compact design. The CFC free refrigerant R404A evaporates at
low temperatures (≤-20°C) and absorbers through this the frictional heat from chamber produced by
the fast spinning rotor. 5 fans serve for even air flow through condenser so that the refrigerant’s
condensing temperature is kept on a low level (lateral front fans are only switched on, if n > 0 rpm).
A specially designed coaxial heat exchanger serves for essential undercooling of the condensed
refrigerant to ensure an optimum evaporation and a perfect operation of the expansion valve. To
maintain low evaporation and resultant condensation temperatures on one hand and to support the
starting procedure of the compressor on other hand, a thermostatic expansion valve with 3.0bara
MOP is used.
The minimum achievable sample temperatures are depending on speed, rotor type and a little on
ambient temperature. After a compensating time, given by the pre-cooling or pre-heating program as
optimal result, the rotor has reached the selected set temperature within a tolerance of ±2K.
To reduce the power consumption of the unit the compressor will not be activated during
accelerating of the motor. When reaching the selected speed the compressor will be activated if a
low temperature had been selected.

1
32 4
0 0
rpm
xg
x g
SORVALL LEGEND
RT
®
4-1
Block Diagram
KEY AND INDICATION BOARD
Speed Detection
2 Pulses/revolution
Imbalance Sensor
Motor
Lid Lock SwitchBrake ResistorBrake Resistor
Overtemp.
M1
3~
R1 R2 R3
M4 S1
F3F4 F5
Overtemp. SwitchLid Lock
Motor
X122
1/2/3
XW1
W
X12
M
X12
V
X17
G
X20
P
X20
B
X20
A
X13
+/-
XD1
D
X4
P/L/PE
F1
F2
Unit's Plug
MAIN BOARD
Resistor for
Speed Limit
Compressor
Fan
Fan for
Compressor
M3 M2
V1
16A
Rotor Detection
p>
PT
100
XR1
R
X14
C
X5
U
X11
C
Compressor
Temp. Sensor
Mains Switch with Over-current Release
Sensors for Lid Lock
Pressure Switch
XI
S0
XXX
a(t)
Multifuge 3S-R / 3L-R / Legend RT
04.07.02 AH
SCHEMATIC DIAGRAMS
Edition: 04

4-2
Wiring Diagram
p>
7820
M2
14 10
11
Î
13
LM2575T-5.0
XD1/R24
13
MAIN BOARD
F5
21bar
F3 F4 S1
+5V
(VCC)
(VDD)
+20V
+24V
+24V
+24V
Chassis Ground Motor
231
142
X12/M X12/V X20/B X20/P
XA2
3
4
Motor
Overtemp. Overpressure
Switch
Lid Lock Switch
Fan for CondenserResistor for
Speed Reduction
M3
R3
NPE L
Mains
Autom. Brake Control
Brake Resistors with
Overtemperature Protector
1
+325V
2
0V
R2
R1
DC Intermediate Circuit
GND
VSS
0V
GND
BYPASS
OVERPRESSURE
FAN1
FAN2
COOLING
2 x 120
Compressor
with Starting Relay
X17/G
2
1
K1
K3
4R7 11W
C
4,0µF
L
C
240µF
S
S0
16A noise filter DC Charging Circuit
120V
X4/L
X4/N
X4/PE
F1
F2
Multifuge 3S-R / 3L-R / Legend RT
04.07.02 AH
SCHEMATIC DIAGRAMS
Edition: 04

4-3
Wiring Diagram
1
2
X122/ 2
1311
2234 +X13/
-
XW/ X14/ 3 5 7
K2
M1
Motor Speed Detection Board Lid Locking Device with
Switches and Sensors
Lid Lock Driving
in:
out:
+
-
+
-
24V
K2
24V
5V
GND
5V
GND
+5V +5V
+5V
GND GND
GND
20V
20V
+325V
0V 0V*
Frequency Converter
Current Control Restistor
µP - Part
XI
XI
KEY AND INDICATION BOARD EASYCONTROL II µC87C54
X5/U1 X5/U2 XR/ 1 2 3
n=0:
n>0:
Temperature Sensor Hall Effective Sensor
V1
PT100

MAIN BOARD
dyn
CPU
NV-RAMEPROM
4467Vxx
0528Vxx
0526Vxx
Physical Separation
RESET
LID_CLOSED
OVERVOLTAGE
OVERCURRENT
MOTOR_OVERTEMP.
ELECTRONIC_OVERTEMP.
OVER_PRESSURE
POWER_FAIL
6 IGBT’s
K3 (BYPASS)
Fan1 (M3)
Fan2 ()
Heating ()
COOLING (M2)
i
LID_LOCK_BRAKE
LID_NEARLY_CLOSED
LID_LOCK_ENABLE
LID_LOCK_CLOSED
LID_LOCK_DIRECTION
LID_LOCK_OPEN
2
3
4
36 4
3
7
3 x 2,5
a(t)
X
X
X
M4
1s
Multifuge 3S-R / 3L-R / Legend RT
04.07.02 AH
SCHEMATIC DIAGRAMS
Edition: 04