Fukuda Denshi FX-2111 User manual

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SERVICEMANUAL
Electrocardiograph
FX-2111
4R2043
FUKUDADEIMSHICO.,LTD.

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Copyright©1
99
7byFukudaDenshiCo.,Ltd.
Nopartofthisdocum entmaybecopied
ortransmi
tt
edinanyformwithout
thepriorw
r i
ttenpermissionofFukuda
DenshiCo.,Ltd.
Manufactured inJapan

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Foreword
AWelistupherethewarningmarksusedinFukudaoperationand
servicemanu
a l
s.
Whenyousen/icetheFX-2111,readthisservicemanualthorough-
lyandpayattentionespeciallytoinstructionsbearingthefol-
lowingmarks:
WarningMarks
Warningmarksusedinoperationandservicemanualsandlabelled
ontheinstrumenthavethefollowingmeanings:
Readthemcarefullytounderstandthemeaningsandmakesureof
thesig nificanceofeachparticular.
A
A
A
Thismarkisusedtoindicatethedirecthazards
Dangerwhichmayleadtothedeathorseriousinjuryofthe
person,maywhollydam agetheinstrument,ormay
c a
usefirehazard,unlesstheinstructionswritten
therearefollo wed.
Thismarkisusedtoin
dic
atetheindirectpotential
Warninghazardswhichmayleadtothedeathorseriousinjury
oftheperson,maywhollydam agetheinstrument
ormaycausefirehazard,un lesstheinstructions
w r
itte ntherearefollowed.
Thismarkisusedtoindicatethepossiblehazards
Cau tionwhichmayleadtoamildormediuminjuryofthe
person,maypartiallydamagetheinstrumentormay
erasedatafromtheco mputer.
NOTE"NOTE"isnotwarninginstructionsbutoffersinfor-
mationtoprev entthepersonfromdoingerroneous
sen/icing.
Ot
he
rMarks
0
A
Noticetoindicategeneralunspecificprohibited
matters.
Noticetoindicategeneralunspecificcaution,warn-
ingorhazard.

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T h
isservice
m a n
ualdes cribestec
h n
icalinfo rmatio nonFX-2111to
aidtheserviceengineerintroubleshooting.
Theman ualisintendedtobeusedbyserviceengineersofFukuda
representativesandauthorizedtechnicalstaffconcernedwithmedicalelec-
tronicequipment.Descriptionincludesrepairingandassemblingmethods
ofeachcomponentunitofFX-2111.Forpartslistsanddiagrams,referto
thePartIIoftheservicema
n u
al.
Theservicemanualconsistsofthefollowingninechapters:
1
.GeneralDescription
TheoutlineofFX-2111,specifications,controlsandindicatorsare
described.
2
.CircuitDescription
Circuitconfigurationandfunctionsareexplained.
3
.Troubleshooting
Troublesvs .c
a u
sesand
c o
unter
m e a
suresaredescri
b e
d.
4
.
Maintenance
Procedurestoreplacethepowerfuse,ROMandbatteryandtoperform
self -testaredescri
b e
d.
5
.PeriodicalInspection
Inspectionprocedurestopre venttroub lesandensuresafeandcom-
pleteoperationoftheinstrumentaredescribed.
6
.CircuitDiagrams
7
.AssemblyDiagrams
8
.
ElectricalPartsLi
s t
s
9
.
StructuralDiagrams
ACaution
0.NeverremodelFukudamedicalelectronicequipment.
.Theservicem
a n
u a
lisintendedfortheservic e
engineersofFukudarepresentativesandthetechni-
calstaffconcernedwithmedicalelectronice
qui
p-
ment.Servicing,reassembling,andadjustmentshall
beperformedbyauthorizedserviceengineers.
.Prepareproperfacilitiesandtoolswhenservicing.
.Besuretofollowtheinstructionsofopera tionmanual
whenoperatingtheinstrument.Foroperatingprecau-
tions,refertotheoperationmanual.
ii

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AServicingPrecautions
ACautionslistedbelowaretheinstructionsofprohibit,danger,warn-
ing,andcautiondescribedinthisserviceman ual.Whentakingthe
procedurebearingthefollowingmark,readthedescriptionthoroughly,
thenstartthetask.
ACaution(page3-2)
Whencheckingthepowersupplyandrelatedcircuitsfortroubleshoot-
ing,takesuff icientcaretoavoidashortcircuit.
ACaution(pag e3-3)
Whencheckingpowerfuses,besuretoturnthepoweroffanddiscon-
nectthepowerplugfromthewalloutletbeforehand.
ACaution

(
pag
e3-8)
Theinsertingpartofkeyconnectorismadeofcarbon.Avoidfrequent
repeateddisco nnectionandconnection.
ACaution(page4-1)
Whenreplacingpowerfuses,besuretoturnthepoweroffanddiscon-
nectthepowerplugfromthewalloutletbeforehand.
ACaution(
pa g
e4-1)
WhenreplacingtheROM,besuretoturnthepoweroff.Al so,takecare
toinstalltheROMincorrectposition.
ACaution(page4-2)
Whenreplacingthebattery,besuretoturnthepoweroffanddiscon-
nectthepowerplugfromthewalloutletbeforehand.
ii i

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ACaution(page4-6)
Disassembling/ReassemblingPrecautions
Besuretodisco nnectthepowercordandmakesuretheinstrument
isturnedoffbeforedisassemblingorreassembling.
.DonotremovethebatterybeforedisconnectanyPCboard.
Takecarethatrepeateddisconnectionofthekeypanelandsensor
boardmayresultinpoorcontact.
Usepropertoolstoloo senscrews.
.Whenreassembling,makesurethatallscrewsaresecurelytight-
enedandallcon necto rsarecompletelyinserted.
PCBoard HandlingPr ecautions
.PCboa rdsareequippedwithhighlysensitivecomponentstostatic
electricity.
.PCboardsarehighlysensitiveelectronicdevices.
PutremovedPC
boardsinaproperprotectivebagortakeappropriatemeasu resto
protectthem.
Handle PCboardscarefully.Ashocktothemmaydamagetheco m-
ponents.
Neverinsertaconnectortothepowe redPCboa rdnorremovethe
poweredPCboard.
ACaution

(page5-2)
Ifyoufindavaluewhichexceedstheallowa blelevel,besuretolet
theuseravoidusingtheFX-211 1.IftheuseroperatestheFX-2111as
itis,he/shemayrece iveanhazardousaccide nt.
EquipmentClassification
TheFCP-2155isclassifiedintothefollowingequipment:
1
.
Protectionagainstelectricalshock
Cl
a s
sI
2
.Typeaga instelectricalshock
App liedpart:TypeCF
3
.Degreeofprotectionagainstharmfulwaterinvasion
Otherequipment
4
.Degreeofsafetyinusingunderair-inflammableanestheticgasesor
oxygen/nitrousoxide-anestheticgases
Equipmentusedunderanenvironmentco ntainingnoinflam
ma b
le
anestheticgase sornoinflamm ablecleaningagent.
5
.Run
ni
ngmod e
Continuousrunningmode
iv

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CHAPTER
1
GeneralInformation
1
.
OutlineoftheFX-211 11-1
2
.
Specifications1-1
2.1Electroc ardiographSection1-1
2
.
2General1-2
2
.
3Environ
m e
ntalConditions1-2
3
.
Controlsan dIndicators1-3
3
.1TopPanel1-4
3
.2SidePanels,LeftandRight1-4
3
.
3Bo
t t
omPanel1-4

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1
.
OutlineoftheFX-2111
TheFX-2111istheeasy-to-usesingle-channelelectrocardiograph
featuringasimpleoperationpanel.Thecompactyethigh-performance
designmakesitsuitablenotonlyforuseintheconsultationroombut
alsofor-carryinginavisittothehospitalwardorpatient
'shomeand
examinationatanemergencysite.
Ithasahigh-densitythermaldotprinterincorporatedtoprovideclear
ECGrecording.TheFX-211 1canoperateoneitherAClineorrechargea-
bleNi-MHbattery.
2
.Specifications
2
.1ElectrocardiographSection
Floatingfromtheground
Standardand
C a
brera12le ads
20MQ
m i
n.(referredto10Hz)
5x10"8max.
1
m V

w i
t
h i
n±5%
Commonmoderejection:10mmorlessperIEC 62DC06test
Inputcircuit:
Lea
d s
:
Inputimpedance:
Inputci rcuitcurrent:
Calibrationvoltage:
Polarizationvoltage:
Timeconstant:
Sensitivitie s:
Frequencyresponse:
ACfilter:
Musclefilter:
DCinput:
Di
sp l
ay:
Recordingsystem :
Paperspeeds:
Chartpapers-
Rollpaper:
Z-
fol
dpaper:
AID
c o
nversion:
Sam plingrate:
m e
thod
±30 0mVmin.
3
.
2secmin.
1/2,1and2cm/m V
0
.
05to150Hz(within-3dB)
50/6 0
H z
,-20dBor
lo w
er
35to45Hz,-3dB(-6dB/oct)
10mm/0.5V,unbal anced,100ki
m i
n.
Liquid-crystaldisplay,20 chars,x2lines
(character:5x7dots)
Therma ldotprinter,8do ts/mm
25and50mm
/s e
cwithin±3%
63mmor50mmwidex30mlong
63mmor50mmwidex20mlong,
75mm/f old
12bits
1ms
1-1

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2
.
2Ge
n e
ral
Safety:
Powerrequirements-
ACoperation:
DC
operation:
Dim ensions:
Weight:
IEC601-1ClassI
.TypeCF
.InternallypoweredequipmentType
CF(IEC601-1)
115VAC,50/60H2;19VAmax.
230VAC,50/60Hz;19VAmax.
9
.6V,7Wmax.(rechargeableNi-MH
battery)
Continuousoperation:app rox.120 min
at20oC(accordingtoIEC62DTesting
Method)
Chargingtime:within3hours
26 (W)x18.2(D)x6.3(H)cm
Approx.1.7kg(excludingbattery)
2
.3Env ir
o n
m
en
talConditions
Operating-
Temperature:10to40oC
Humidity:30to80%RH(nodewcondensation)
Atmos phericpressure:70to106kPa
Transportation&Storage-
Temperature:-10to40oC
Humidity:10to95%RH(nodewco ndensation)
Atmosp hericpressure:70 to106kPa
1-2

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3
.
ControlsandIndicators
TopPanel
@PaperMagazine
31-
k»
XLiquid-crystalDisplay
(DOpe rationPanel
LeftP
an e
lRightPanel
®PotentialEqualization
Terminal
o«
0
00
F3
D
©PowerConnector
©MainPowerSwitch
Q
@DCInp utTerminal
©LeadConne ctor
BottomPan el
©FuseHolders
@
o
{
Ii<
iii
*
0
§)
~
0
~
®0
"©RechargeableeatteryRoom
1-3

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3
.1TopPanel
©Display:Indicatescurrentstatussuchasrecordingmode,lead,sensitiv-
ity,heartrate,orprogramsetting.
©OperationPanel:
ONTurnstheFX-2111oninDCoperation.
OFF

TurnstheFX-2111offinDCoperation.
PressingthiskeyduringACoperationletstheFX-2111enterthe
chargemode.
ModeSelectamodeinthefollowingorderwhenpresseddu ringcessa-
tionofrecording:
|->Automaticrecording-»Manualrecording->Programming-|
HoldingthiskeyduringautomaticrecordingletstheFX -2111record
thecurrentleadco ntinuouslyuntildetached.
Holdingthiskeyduringmanualrecordi ngletstheFX-2111reco rd
aneventmarkuntildetac
h e
d.
Sensitivity

Selectsarecordingsensitivity.
Lead Select<Selectaleadforrecording.Inprogrammingmode,thesekeysallow
youtoselectasettingvalue.
ResetResetsthemeasuringcircuitwh ileheldduringrecording.In
programmingmode,thiskeyselectsasettingparameter.
1mVAppliesa1
mV
calibrationwaveformwhenpressedduringrecord-
ing.Inprogramm ingmode,thiskeyselectsasettingparameter.
Start/StopStartstheFX-2111recordingtheECGwaveform.Anotherpressstops
itfromrecording.
©PaperMagazi
ne
:A
cc o
mmodatesachartpap er.
3
.2SidePanels,LeftandRight
®DCInput:
©LeadConnector
©PowerCon
ne
ctor
©MainPowerSwitch:
@PotentialEq
ua
lization
Ter
m i
nal:
InputsexternalDCsignalswithasensitivityof10mm/0.5V.
C
o n
ne
c t
stothel
e a
dc
a b
le.
Con nectstothepowercable.
TurnsACpoweron/off.
MakestheFX-2111equipotentialtoanotherinstrumentusedincom-
b i
nationwithit.Tothateffect,
c o
nne ctbothinstrumentstoa
commongroundingco nductorusinganoptionalgroundingwire.
3
.
3BottomP
a n e
l
©BatteryRoom:
©FuseHolders:
HousestherechargeableNi-MHbattery.
Havepowerfusesinserted.
1-4

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CHAPTER
2
CircuitDescription
1
.
Introduction2-1
2
.IsolatedInputCircuit2-2
2
.
1BufferAmplifierandRFDriver2-2
2
.
2
Le a
dNetworkandLeadSelector2-3
2
.3Preamplifierand1mVGen erator2-3
2
.4R-waveDetectorandOverinputDetector2-4
2
.5AmplifierControl2-5
2
.6SignalIsolator2-5
2
.
7PowerIsolator2-6
3
.MiddleAmplifierandAIDConverter2-6
3
.
1MiddleAmplifierandDCInput2-6
3
.
2AIDConverter2-7
4.MotorControl2-8
5
.
Sen sorCircuit2-8
5
.
1DetectionofMagazineOpenCondition2-9
5
.2DetectionofPaperEndandPaperMarks2-9
6
.
CPUCircuit2-9
6
.
1ResetCircuit2-9
6
.
2CPU,ROMandRAM2-9
6
.3GateArray2-9
7
.
LCDControlCircuit2-11
8
.
Th
er m
alPri nt
He a
dControlCircuit2-11
9.MemoryBackupCircuit2-12
10.PowerSupplyandChargingCircuit2-13
10.1Introduction2-13
10.2Rectifier/SmoothingUnitandON/OFFControl2-13
10.3+10Vand+5VdPowerGenerators2-14
10.4±5VaPowerGenerator2-15
10.5+24VPowerGenerator2-15
10.6ChargingCircuit2-16

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1
.
Introduction
TheFX-2111isco mposedofthefollowingci rcuits:
(1)MainBoardPCB-6409
-Isolatedinputci rcuit
-MiddleamplifierandAIDconvertercircuit
-Motor
c o
ntrolcircuit
-Sensorcircuit
-Resetcircuit
-CPUcircuit(CPU,ROM,RAM,gatearray)
-LCD
c o
ntrolcircuit
-Thermalprintheadcontrolcircuit
-Memorybacku pcircuit
-Powersu pplyandchargingcircuit
(2)SensorBoardPCB-6239
(3)ACInletBoardPCB-6410
ECGsignalsinputthroughtheleadconnectorareamplifiedbythe
isolatedinputcircuitandthemiddleamplifiercircuit,thenco
nv
ertedfrom
analogtodigitalsignalsbytheAIDco nvertercircuit.Thedigitizedsignals
aredigitallyfiltered,ifthefilterissettoON,thensentthroughthegate
arraytothetherma lprintheadco ntrolsothat theyarerecordedasECG
waveformbythethermalprinthead.
Duringtheseprocesses,theheartratedetected
by
ahardware
techniqueandoperationstatussuchasfilterON/OFFsettingaredispla ye d
ontheLCD.
Thepowersupplyprovidescircuitswithnecessa rypowers.The
chargingcircuit,ifactivated,chargestheNi-MHbatteryinACoperation
ortransfersthepowerfromtheNi-MHbatterytothepowersupply.The
stateofbatteryisindicatedontheLCD.
"
e
O
3
PCB-6
4 0
9
-
::pcb-
6 4
io
IsolatedInputCircuit
DC
Input
DC
Motor
Thermal]
Pri nt
Head
If
LCD
i5V
I0V
i-24V
VDO
+2
.
5V
PowerSup ply
ZEE
ACIn let
ACPower
'
-/Charging;-;
'
AyiCircuil;--
NiMH
Battery
Moto r
Control
5Mmt:'
JGateArray,KeyPane l
PUCircuit
The rmal
*Printit
.
He ad[
Control
1
LCD
Con trolBacku p
Circuit
CB-.
Sensor
6239
B
o a
rd
OverallBlockDiagram
2-1

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2
.IsolatedInp
ut
Circuit
Theisolatedinputci rcuitiscomposedofthefollowing:
(1)BufferamplifierandRFdriver
(2)Leadnetworkandleadselector
(3)Pr eamplifierand1mVgenerator
(4)R-wavedetectorandoverinputdetector
(5)Am plifiercontrol
(6)Signalisolator
(7)Powerisolator
R
L
F
CI
I
C6
RFDrive<-
-5
2
-5
"
1
Dc
D
.
5
-
5-5
55
ta5
-
I2
RF
-5
-5
I
O
I
"
S
T
-
5Preamplifier
1mV
ECG
">Signal
Isolator
RESET
Amplifier
Control
Overinput/
R-WaveDetector
Circuit
Signal
Isolator
(Photo
Coupler)
I
i
i
.e-Pow er
Isolato r<-
BlockDiagramofIsolated Input Circuit
2
.1BufferAmplifierandRFDriver
oac-Hiticr
9ISO*
3
I
0.
5
Sincethebufferamplifiershouldinputsignalswithhighimpedance
andoutputthemwithlowimpe dance,itisconfiguredasanimpe dance
conversioncircuitusinganoperationa lamplifier.Thecircuitshownabove
isindividuallyappliedtoalllea dsexceptforRF(rightfoot).Also,alimiter
usingadualtransistorismountedforprotectionagainstoverinput.
TheRFdriverfeedsbackthecompos itesignaloflimbleadstothe
rightfo
ot
forimprovedcommonmoderejectionratio.
2-2

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2
.
2LeadNetworkandLeadS
el
ector
OK
211
OK
*a?i
z10
Ox
>-
3
04
OK
i
201
0*
?io«r
It:?
t:
Ok4;
200
0-<
I
'
JEl
0«
OK
10*
Tan
m
lOXt
TUNS2L]
Leads
LeadSelectSignals
ABCD
STD0000
1000
II0100
II I1100
aVr0010
aVL1010
aVF0110
VI
1 1
10
V2 0001
V31001
V40101
V51101
V
6 0
011
Thelea dnetworkisfo rmedwithresisto rsandlea dselecto r,withmulti-
plexorsIC36,IC38,IC41andIC4.Inputsignalstomultiplexorsareselected
fromRA,LA,LF,andCItoC6accordingtofou rsignalsofA,B,C,and
D
,thensynthesizedtoproduceeachECGlead(seetableabove).
2
.3Preamplifierand1mVGenerator
4in*
i_
*.««
f4="[F
MOK <cm.J
_
?i
o.onr-*
-iJift51
|Slr4i»i
c«icb>rc
10m
JOK
(CJ7I
®
a
OIL
1SS
.mi1*3
5:
Aicia
®
1J
LIt004C$l-i.
2
rc
C-1fcTzOOHK
o.aou
r-II
"VX.
.200CCC
1171
1.IK
t
3Con*
rmioi
2
.
3
.
1Preamplifier
Sig
na
lsoutputfromthelea dselector(multiplexors)areamplified8
timesby adifferentialamplifier,then25timesbyanoninvertingamplifier,
therebylett ingtheisolatedinputcircuitamplifytheinputsignalsby20 0
timesintotal.Signalsoutputatthefirststagearesenttotheoverinput
detector.
2-3

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The3.5Miresistorand1|jFcapacitorsetthetimeconstantat3.5
se
c o
nds.
2
.
3
.
21mVGen
e r
ator
The1mVgeneratordividesthehigh-precisionvoltagereferenceout-
put of1.2
35
Vbyahigh-precisionresistor,therebyapplyinga8mVvoltage
tothepreamplifierwhenthe1mVapplicationsig nalisatalowlevel.
2
.4R-waveDetectorandOverinputDetector
4*2
U*f 11 1
er aQ.Qit
Li
C«2
[C41C
J.
*
*in>
10QN
nrvr-!>-
I4MlOOH
@
0.
23
JOCK
4
111
0.1J..»2
CP
a*]
UM fILI
tIla
r-
C42«
0.001J
C12J"I
20 OK
re
2
.
4
.
1R-waveDetector
RAandLFsignalsofleadnetworkaresynthesizedtoIIlead.TheR-
wavedetecto rdetectsRwavebypickingupR-wavecomponentfromthe
IIleadsignalthroughaband-passfilter,thensendingittoaco mparator.
2
.
4
.2OverinputDetector
Thesignaloutputatthefirststageofpreamplifierissenttoacom-
paratorandifthesignalexceeds±360mV,theoutputofthe
com
parator
be
c o
m e
sinverted.
SignalsoutputfromtheR-wavedetectorandoverinputdetectorare
adjustedinthepulsewidthbythemultivibratorIC40(TC45 38),theninput
intothephotocoupler.
+0
.
31V
1T63
TP19
TP20
ov
-0.31V
OV
+2
.
9V
-2
.
9V
*170»S
ITOins
R-waveD
e t
ectionWavelormOverinputDetectionWaveform
2-4

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2
.5AmplifierControl
2£
n5
IT
1
Sia
<5
*of3
*-"CCS.IK
id-
®.217
IKHJU
lO.Ot
.1
-v0CO
XL
~
1
Thiscircuitpicksupareset,1mV,orlea dselectsignalfromtheserially
transferredamplifiercontrolsignals.
!<-%1ms

;
I
1KH2
AMP
CLK
AMP-
DATADOD7D6D5D4D3D2DlDOD7D6D5D4D3D2DLDOD7DO
i
i
OLDDATA<-i
i
->NEWDATA
8ms-5
Responsetime:32ms+amax.？ 0

_
a08ms
16ms+amm.
Dat awfit len(romCPUarelatche d.
2
.6SignalIsolator
<flrCLKH
O-
frwrr>-
lMIK
--W
11 1*
CE3d>
t
-
LTT-
Ten
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ri
r
i
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rLji_.
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milIk
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0. 01O.Ol o. ot
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c
BIO-
ISI«3)
4
1i
1
Cr-
ThesignalisolatormodulatesinputanalogECGsignalswithFETs
Q31andQ32andpulsesTRF1+andTRF1-,thentransfersthemodulated
signalsthroughtheT1isolationtransformer(1:1).FETsQ22andQ23
demodulatethesignals.Alow-passfilterformedwithcapacitorsand
resistorsintwostageseliminatesnoiseinthedemodulatedsignals.
Digitalsignals(AMPCLK,AMPDATAandHR)aretransferredusingaphoto
co
up ler.
2-5

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2
.
7PowerIsolator
<ianz>
11ISV,.
.
*fsl\viSiiQl
<3B£J-pW-if
s0r
'
JC10 *
i-r--r-
'2
<2i rD-«-f-1J-
T
T
lisjoj
0.1
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-020
30«ilO
JH
1
r
1
5p
1
ISSIOJ*a.,
T
C10
200xh i
Thepoweristransferredusing10Vpulseat100k
Hz
.Attheisolated
side,a3-termi nalregulatorsupplies±5V.
3
.MiddleAmplifierandAIDCo
nv
erter
3
.1MiddleAmplifierandDCInput
C4T
i
_
£»:v.\]°
-
at
i
3;
*110.0.2
-»1
1
.
LA
il-Lt0.
21
irrw>
"10.?
...
imraT>
ECGsignalsdemodulatedattheisolatedsignaltransmissionsection
areoutputtothemiddleamplifierjustafterpassingthroughalow-pass
filterformedwithcapacitorsandresistorsintwostages.Themiddleam-
plifieramplifiestheinputsignals1.25ti
m e
stoatotalgainof250times
andsendsthemtotheAIDconverter.SignalsoutputfromtheAIDconverter
aredigitallyfilteredwithasoftwaretechnique.Theisolatedinputcircuit
andthemiddleamplifieraredesignedsoastoprovideageneralhard-
warefrequencyresponseof150Hz(-3dB).
TheDCinputamplifiesinput signals0.5times,thensendsthesignals
totheAIDconverterthroughabufferamplifier.
2-6

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3
.
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TheA/Dconverterisasingleslopetype.Itiscom posedofatriangular
wavegenerator,sample&holdci rcuit,andcomparator.Thecomparator
comparesinputsignalswith±3.2\/trianglewavegeneratedatevery1ms.
Thesignalsarethenconvertedfromthevoltagetoapulsewidthandtrans-
ferredtothegatearray.Inthegatearray,thepulsewidthiscounted,then
co nvertedintoadigitalvalue.
A/DCLK
S/H
(TP35)
Triangular
(TP7)
Si
5k480,1s
20ps
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Startolcounting
A/DConversionTiming
+3
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2V
-3
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2V
BesidesECGsig nals,theAIDconverterdigi tizesDCinputsignals,
ba
tteryvoltage,thermistorsignalsofthermalprinth
ea
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encevoltageof2.5VforcalibrationofA/Dconversion.
2-7

7/16/2019 Fukuda Denshi FX-2111 ECG - Service Manual (1)
http://slidepdf.com/reader/full/fukuda-denshi-fx-2111-ecg-service-manual-1 20/128
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MotorControl
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ThemotortodrivetherecorderistheDCmotorwh ichhasaphoto
sensorbuiltinfordetectionofmotorspeed.ThePLLcontrolIC25com-
paresasig naldetectedbythephotosensorwiththereferencefrequency
inphase,therebyprovidingamotorcontrolsig nalatpin13ofIC25.
Themotorcontrolsignalgoestotheintegratorcircuitformedwith
R140,R142,andC64andismadebyapropermotordrivevoltageofthe
PWMcontrolIC24.
25mm/s(256Hz)SOmr
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r
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IC25(pin14)
SIN
IC25(pin3)
CIN
IC25(pin13)
P2
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.OV
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.+3
.
IV
+2
.
2V
OV
Early
Thesensorcircuitisprovidedtocheckforamagazineopeni ng
conditionandpaperendaswellasdetectingpapermarks.
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