B+K precision 4051 User manual

OperatingManual
B+KPRECISION4051
Multi-FunctionGenerator
99 Washington Street
Melrose, MA 02176
Fax [phone]
TestEquipmentDepot.com

Page1
BKPRECISIONMODEL4051
OperatingManual
TableofContents
Warranty:InsideFrontCover
SectionOne:GENERALINFORMATION
  

1.1
-
INTRODUCTION
1.2-FEATURES
1.3-UNPACKINGANDINSPECTION
1.4-INSTRUMENTIDENTIFICATION
1.5-INSTRUMENTPOWERANDCARE
SectionTwo:FUNCTIONS
2.1-INTRODUCTION
2.2-FUNCTIONKEYSWITCH
2.2.1-“CAL”KEY
2.2.2-“SOURCE”KEY
2.2.3-“SWEEP”KEY
2.2.4-“BURST”KEY
2.2.5-“MOD”KEY
2.2.6-“SET”KEY
2.2.7-“RNGUP”KEY
2.2.8-“RNGDN”KEY
2.2.9-“WAVEFORM”KEY
2.2.10-“SYM”KEY
2.2.11-“OFFSET”KEY
2.2.12-“LOGIC”KEY
2.2.13-“ADJUST”KEY
2.2.14-“FUNCTION”KEY
2.3-CONTROLKNOB
2.3.1-DIGITALENCODER
2.3.2-AMPLITUDEPOT
2.4-BNCOUTPUTANDINPUTJACK
2.4.1-50OHMOUTPUT
2.4.2-TTL/CMOSOUTPUT
2.4.3-EXT.COUNTERINPUT
2.4.4-VCG/MODINPUT
2.4.5-BURSTINPUT
2.5-LOGIC/DVMPROBEJACK
2.6-TRIPLEOUTPUTDCPOWERSUPPLYJACK
2.6.1-+VsJACK
2.6.2--VsJACK
2.6.3-+5V/3.3V(VCC)JACK
2.6.4-GNDJACK
2.7-RESETSWITCH
2.8-POWERON/OFFSWITCH
2.9-LCD
2.10-RS-232CSERIALPORT
2.11-VCGOUTPUT
2.12-HEATACTIVATEDCOOLINGFAN
SectionThree:OPERATION
3.1-THEORYOFOPERATION
3.2-BASICFUNCTIONGENERATOROPERATION
3.2.1-COARSEFREQUENCYADJUSTMENT
3.2.2-FINEFREQUENCYADJUSTMENT
3.2.3-FREQUENCYLOCKING
3.2.4-RANGINGSELECTION
3.2.5-WAVEFORMSELECTION
11
11
12
12
12
12
12
12
12
13
13
13
13
13
13
13
13
13
14
14
14
15
15
17
18
18
19
19
19
19
9
9
9
9
10
10
10
10
10
10
11
11
11
11
5
5
7
7
7

Page2
3.2.6-DUTYCYCLE(SYMMETRY)CONTROL
3.2.7-DCOFFSETCONTROL
3.2.8-OUTPUTLEVELAMPLITUDECONTROL
3.3-SWEEPOPERATION
3.4-BURSTOPERATION
3.5-MODULATIONOPERATION
3.6-MULTIPLEFUNCTIONOPERATION
3.6.1-AUTORANGINGFREQUENCY(EXT.CNTR)
 
COUNTEROPERATION
3.6.2-LOWFREQUENCYCOUNTEROPERATION
3.6.3-TOTALIZECOUNTER(TOTAL)OPERATION
3.6.4-DIGITALVOLTMETER(DVM)OPERATION
3.6.5-CMOSLOGICOUTPUTLEVEL(C-LEVEL)
 
ADJUSTMENT
3.6.6-POSITIVEPOWERSUPPLY(+Vs)ADJUSTMENT
3.6.7-NEGATIVEPOWERSUPPLY(-Vs)ADJUSTMENT
3.6.8-LOGICPOWERSUPPLY(Vcc)CONTROL
3.7-TTL/CMOSLOGICCONTROLOPERATION
3.8-PROGRAMMEMORYOPERATION
3.8.1-PROGRAMMEMORYSTORAGEOPERATION
3.8.2-PROGRAMMEMORYRETRIEVAL
3.9-COMPUTERREMOTECONTROLOPERATION
3.10-RESTOREFACTORYDEFAULTSETTINGS
3.11-INPUTANDOUTPUTPROTECTION
3.11.1-BNCOUTPUTJACK
3.11.2-BNCINPUTJACK
3.11.3-LOGIC/DVMPROBEINPUT
3.11.4-POWERSUPPLY
3.12-ONE-STEPOUTPUTAMPLITUDECONTROL
3.13-LOGICPROBEOPERATION
3.14-LIMITATIONSOFTHENEGATIVEPOWERSUPPLY
SectionFour:OPERATINGSTEPS&TROUBLESHOOTING
4.1-INTRODUCTION
4.2-BASICFUNCTIONGENERATORMODE
4.3-FREQUENCYSWEEPINGOPERATION
4.4-OUTPUTSIGNALBURSTOPERATION
4.5-OUTPUTSIGNALMODULATIONOPERATION
4.6-FREQUENCYCOUNTER,LOWFREQUENCY
COUNTER,ANDTOTALIZECOUNTEROPERATION
4.7-MULTI-FUNCTIONSIMULTANEOUSOPERATION
4.8-POSITIVEANDNEGATIVE(+Vs&-Vs)POWER
 
SUPPLYADJUSTMENT
4.9-CMOSOUTPUTLEVEL(C-LEVEL)ANDADJUSTMENT
4.10-PROGRAMMEMORYOPERATION
4.11-RS-232CCOMPUTERINTERFACEEXAMPLE
4.12-TROUBLESHOOTINGGUIDE
SectionFive:SPECIFICATIONS
SectionSix:PANELDIAGRAMS
20
21
22
22
24
26
28
28
29
30
30
31
32
32
33
33
34
34
34
35
36
36
36
36
37
37
37
38
38
39
39
39
40
41
43
43
44
44
45
45
47
49
52

Page5
GENERALINFORMATION
SECTIONONE:GENERALINFO
1.1
INTRODUCTION
The
MODEL4051
programmablemultifunction
generatorisanexceptionallyversatileandeconomical
instrumentforapplicationsinR&D,Manufacturing
Tests,ServiceRepair,andTraining.Featuringan
adjustabletripleoutputpowersupplyandwaveform
generator,ithastheabilitytoprovidepowerand
signalsourcesforacircuitwhiletheuniversallogic
probe,auto-rangingfrequencycounter,anddigital
voltmeterallowuserstosimultaneouslyanalyze
andmeasurecircuitactivity.Thiscompactdevice
combinesthefunctionalityofvestandardlaboratory
instrumentsintooneintegratedunit,makingthetask
ofswitchinginstrumentsaseasyaspressingabutton.
1.2
FEATURES:
•
Autorangingfrequencyandlowfrequencycounter
coversthemeasurementrangefrom0.04Hzto
35MHzwithxedTTL/CMOSlogicthresholdor
variabletriggeringlevel.
•
Totalizecountercountsupto999999counts.
•
35MHzuniversallogicprobeforTTLlogicand
CMOSlogic(from3Vto16V),displayallthe
logicstateswithsixdifferentuniqueformats.
•
4-digitauto-rangingDCVoltmetercoversthe
range±0~250V.
•
TripleoutputsPowerSupply:
1)
5V/3.3Vlogicsupply,with5Aoutputcurrent.
2)
+Vsvariable0to+24V,with1.5Aoutputcurrent.
3)
–Vsvariable0to–24V,with1.5Aoutputcurrent.
+Vsand–Vssupplycanbeseparatedordual
trackingadjusted,andeachsupplyhasshort
circuit,overcurrent,andovertemperature
protection.Digitaldisplaymonitorseachsupply
voltagewhilethesupplyisbeingadjusted.
•
MemoryBackupforprevioussettings,allowing
thisunittoworksimilartoaconventional
mechanicalswitchoperatedinstrument.All
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX [phone] - TestEquipmentDepot.com

Page6
GENERALINFORMATION
previoussettingsareretrievedandtheprevious
adjustedquantitydisplaysontheLCDbargraph.
Thedigitalencodercanadjustandmemorize
upto18activequantities,allowuserstoswitch
betweenfunctionswithoutlosingalreadymade
adjustments.
•
Autofrequencylockingcapability—unlike
conventionalfunctiongenerators,theoutput
frequencyoftheMODEL4051canbe
automaticallylockedwithin±0.2%range
atthetunedfrequency,withoutdriftcaused
bytemperature,moistureorcomponent
degeneration.
•
Onetimesetupprogrammemory—providesdata
memorywhichcanstoreuptotendifferentles
andcanberetrievedwithasinglekeystroke.
•
RS232interfaceport—enablesnetwork
connectivitybyacomputertoperformremote
monitoringorcontrolofsensorsoractuatorsin
correctiveoranalysisapplications.
modes,settings,andquantityadjustmentsinuse
arememorizedandcanberestoredimmediately
afterpowerup.
•
LCDBack-lightdisplay—highbrightness,uniform
coldcathodeuorescentlampback-lighting
providesahighcontrastdisplayeasilyreadable
frommultipleanglesevenfromadistance.
•
Sweepfunctiongeneratorcoveringthefrequency
rangeof0.14Hzto20MHzwithlarge6-digit
display,CoarseandFineadjustments,DCoffset
andDutycyclecontrols,Waveformprovided
withSine,Triangle,Square,Saw-tooth,±Ramp,
±Pulse.WithoperatingmodesofNormal,
Sweep(linearorlogarithm),Burst(singleor
multiple),Modulation(FMorAM),VCG.Output
amplituderangeof20mVto20Vp-p.TTL/CMOS
logicoutput:CMOSoutputlevelcanbeadjusted
from3.0Vto16.0V.TheTTLsignalcanbe
switchedbetween5Vor3.3Voutput,ithasthe
samefrequencyasthemaingenerator.
•
Userfriendlykeyswitchoperation—Asfunction
keysarepressed,correspondingfunctionsand

Page7
GENERALINFORMATION
identifyyearofmanufacturing,thesecondtwodigits
identifythemonth,andthelastfourdigitsrefertothe
manufacturedrunquantity.
1.5INSTRUMENTPOWERANDCARE
TheACpowerisinternallysetfor120Vor220VAC
byajumper.Thepowersettingismarkedclearly
onthebackpanel.Besuretocheckthebackpanel
beforeconnectingthelinevoltage.Thelinevoltage
mustbewithin±10%ofthesettingvoltage.Line
frequencymustbewithinarangeof46Hzto68Hz.
Theinstrumentshouldnotbeturnedonandoff
quicklyandrepeatedlyaslossofdatasavedinsystem
memorymayresult.
Replacementfusesmustbe2Aforthe120VACor1
Aforthe220VAC.ThefuseholderisinsidetheAC
powerreceptacle.
IftheMODEL4051needscleaning,therubberboot
canbeeasilyremovedforcleaningpurposes.To
reassembletherubberboot,pushthefourrubbertabs
backintotheirholeswithapinorasmallscrewdriver.
1.3
UNPACKINGANDINSPECTION
TheMODEL4051multi-tasklabinstrumentwascarefully
testedandinspectedbothmechanicallyaswellas
electronicallypriortoshipment.Uponreceivingthe
instrument,carefullyunpackallitemsfromtheshipping
cartonsandinspectthemforanyobvioussignsof
physicaldamagethatmayhaveoccurredduringdelivery.
Reportanysuchdamagetotransitagentimmediately.
Saveboththepackingboxandfoamblocksforfuture
useincasere-shipmentisrequired.Afterunpackingthe
system,checkforthefollowingincludeditems.
•
Oneprogrammablemultifunctiongenerator
•
Onelogicprobe
•
OneBNCcable
•
OnePowerCord
•
OneOperatingManual
1.4INSTRUMENTIDENTIFICATION
EachBKPrecisioninstrumenthasaneight-character
serialnumber(e.g.04120015).Thersttwodigits

Page9
FUNCTIONS
SECTIONTWO:FUNCTIONS
1.1INTRODUCTION
Push-buttonkeyswitchesaccessallfunctionsofthe
MODEL4051.Keysmaybededicatedormultiplexed
withmultiplefunctionassignments.Asafunctionkey
ispressed,arelatedfunctionstatusmessageisshown
ontheLCDdisplay.Thedigitalencodercanadjustand
memorizetheactivequantityofeachaccessedfunction,
allowingtheusertoswitchbetweenfunctionswithout
losingalreadymadeadjustments.OutputandInput
connectionstotheMODEL4051areprovidedthrough
BNCjacks.Fourbananajacksareavailableforusewith
thetripleoutputpowersupply.
Note:
BKPrecisionalsoofferstheMODEL4050,aspecially
conguredMODEL4051withoutatripleoutputpowersupply.
2.2FUNCTIONKEYSWITCH
TherearefourteenkeyswitchesaroundtheLCDdisplay.
Eachkeycapisprintedwiththenameofadedicated
functionorageneralcontrolname.Whenafunction
keyispressed,on-screenmessagesappeartoindicate
theactiveoperation.
FunctionKeyButtons:
CAL,SOURCE,SWEEP,BURST,MOD,SET,
RNGUP,RNGDN,WAVEFORM,SYM,OFFSET,LOGIC,FUNCTION,
ADJUST.
2.2.1“CAL”KEY
WhiletheMODEL4051issetinfunctiongenerator
mode,theCALkeycanresetthe50OHMoutputsignal
to50%dutyandtheDCoffsettozero.Operatinginthe
Positive(+VS)orNegative(-VS)powersupplyadjustment
mode,thiskeyenablesorinhibitsthe“Tracking”
adjustmentmodeforbothpowersupplies.The“CAL”
keyalsorestoressavedsettingsfromprogrammemory.
2.2.2
“SOURCE”KEY
ThecontrolsignalforSweep,Burst,andModulation
operationsofthefunctiongeneratorcanbeselected
eitherfromanInternal(INT)orExternal(EXT)source.
TheSOURCEkeytogglesbetweensourcesforthe
controlsignalwhenpressed.Bydefault,functionsare
setto(INT)mode.TheSourcekeyalsoservesasthe
entrykeytoProgrammemory,eitherformemorystorage
ormemoryrecalloperations.InSINGLEBURSTmode,
theSOURCEkeyisusedtoreasinglepulsemanually
whenTIMEissettothemaximumquantity.

Page10
FUNCTIONS
2.2.3.“SWEEP”KEY
Thefrequencysweepingfunctioncanbeselectedeither
inLinear(LIN)orLogarithm(LOG)mode.Pressingthe
SWEEPkeycantogglebetweenthesetwooperations.
BydefaulttheSweepfunctionissettoLINmode.
2.2.4“BURST”KEY
Theoutputsignalfromthe50OHMBNCJackcan
becontrolledasasingle(SINGLEPULSE)Burstora
multiple(MULTP)Burstofapulsetrain.Pressingthis
keycantogglebetweenthesetwotypesofoperations.
BydefaulttheBurstfunctionissettoSINGLEmode.
2.2.5“MOD”KEY
Themaingeneratoroutputcanbemodulatedbyan
internalsignal(astandard1KHzsinewave)oran
externalsignalfromtheVCG/MODBNCJack.Pressing
thiskeyselectsbetweenfrequencymodulation(FM)
orAmplitudemodulation(AM).Bydefault,the
modulationfunctionissettoFM.
2.2.6“SET”KEY
Undernormaloperation,theSETkeyturnsthe
backlightoftheLCDdisplayonoroff.Whenthe
functiongeneratorissettoperformaSweep,Burst,
orModulationoperation,thiskeyallowstheuserto
strobeeachstepandadjustquantityduringsetup.
Thiskeyalsoallowstheusertostorecurrentsettingsto
programmemory.
2.2.7“RNGUP”KEY
Pressingthiskeycanincreasetheoutputfrequencyby
adecadeuntiltherangereaches20MHz.Thecurrent
rangeisdisplayedbythesideofthiskeyinatotalof
eightdifferentranges.
2.2.8“RNGDN”KEY
Pressingthiskeycandecreasethefrequencyrangebya
decade,untiltherangereaches2Hz.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX [phone] - TestEquipmentDepot.com

Page11
FUNCTIONS
2.2.9“WAVEFORM”KEY
SelectsthewaveformoftheoutputsignalSine,Square,
orTrianglewaveform.Thedisplayedwaveformbythe
sideofthiskeyisthecurrentoutputwaveform.
2.2.10“SYM”KEY
Thiskeyenablesthedutycyclefunction,whichadjusts
thesymmetryofthemainoutputsignalandTTL/CMOS
signal.Thearrowsignsonthedisplay(

or

)
indicatestheadjusteddirection.Forasignalwitha
dutycycleotherthan50%,oneofthearrowswillbe
displayedconstantly.
2.2.11“OFFSET”KEY
ThiskeyenablesDCoffsetadjustmentofthemain
outputsignal.Thepositiveandnegative(+),(-)signson
thedisplayindicatesthedirectionoftheDCoffset.As
longasanoffsetexists,asignwillbedisplayed.
Secondaryfunction:
Inmultifunctionsequencemode,
thiskeyservesasthebackwardkey.
2.2.12“LOGIC”KEY
SelectsthelogicsignalforTTL5V,TTL3.3VorCMOS
LogicattheTTL/CMOSoutputJack,thelogicthreshold
levelsofthelogicprobe,thetriggeringlevelsofthe
counters,andthelogicpowersupply(Vcc)outputs.
2.2.13“ADJUST”KEY
Pressingthiskeyatanytimewillabortotherfunctions
andenterintofunctiongeneratorcoarsefrequency
adjustmentmode.Thiskeycanthentogglebetween
coarseandnefrequencyadjustments.Thetypeof
quantitybeingadjustedisindicatedbytheblinking
signdisplayedabovethe“ADJUST”key.
2.2.14“FUNCTION”KEY
Controlsfunctionsanddisplaysforoperations
outsideofthefunctiongenerator.Presstostartthe
multifunctionsequencemode.Uponenteringthis
multifunctionsequence,eachadditionalpressofthe
“FUNCTION”keyadvancesforwardonestepinthe
sequence,the“OFFSET”keystepsbackward,andthe
“ADJUST”keyabortsthesequence.
or
or


Page12
FUNCTIONS
OntheMODEL4051,thefunctionsequenceadvances
inthefollowingorder:
Note:
OnthespeciallyconguredMODEL4050unit,thesequence
loopstothebeginningaftertheCMOSLevelfunctionsinceitlacks
theMODEL4051’stripleoutputpowersupply.
2.3CONTROLKNOB
Therearetwocontrolknobsonthefrontpanel,oneis
dedicatedtothesignaloutputlevelcontrol,andthe
otherismultiplexedforallotheradjustments.
2.3.1DIGITALENCODER
Thedigitalencodercanadjustandmemorizeupto
18activequantities,allowinguserstoswitchbetween
functionswithoutlosingalreadymadeadjustments.The
activeitembeingadjustedbytheencoderwillblink
ontheLCD.Thefullrangeofeachadjustablequantity
correspondstothetwelvesectionsofthebargraph.
2.3.2AMPLITUDEPOT
Controlstheamplitudeofthesignalattheoutputjack
with20Vp-pintotheopencircuit,10Vp-pintothe
50OHM.Attenuationfactorscanbeatotalof–40dB
fromthemaximum.
2.4BNCOUTPUTANDINPUTJACKS
ThereareveBNCjackslocatedontherightsideof
thefrontpanel,twoforoutputsignalsandthreefor
inputsignals.
•2.4.150OHMMAINOUTPUT
UsedformainfunctiongeneratoroutputwithsuperimposedDC
offsetandDutycycleadjustment.
•2.4.2TTL/CMOSOUTPUT
ProvidesTTL5V,TTL3.3VorCMOSsquarewaves.When
theselectedoutputwaveformisthesquarewaveform,ithas
thesamefrequencyanddutycycleasthemainoutput,butis
independentofoutputlevelcontrolfromtheAmplitudePotand
DCoffsetcontrols.
•2.4.3EXT.COUNTERINPUT
Usedformeasuringthefrequency(3Hzto35MHz)ofasmall
amplitudesignalorasignalwithDCbias.Thisinputjackaccepts
ACcouplingonlyandtheinputsignalmustbegreaterthan3Hz.
FunctionGenerator->Freq.Counter(EXTCNTR)->LowFreq.
Counter(EXTCNTRTOTAL)->TOTALIZECounter(TOTAL)->
DigitalVoltmeter(DVM)->CMOSlevel(C-LEVEL)->Positive
Supply
*
(+Vs)->NegativeSupply
*
(-Vs)->LogicSupply
*
(Vcc)

Page13
FUNCTIONS
•2.4.4VCG/MODINPUT
UsedforexternalcontrolsignalinputforSweepormodulation
operationswhentheSOURCEkeyistoggledtoEXT.InSweep
operations,thisjackisusedforVoltageControlGenerator(VCG)
Input.Ahigherpositivevoltagewilldecreasethegenerator
outputfrequency.InModulationoperations,thisjackisusedfor
modulationinputsource.
•2.4.5BURSTINPUT
UsedtoinputanexternalgatingsignalforBurstoperations.The
userisabletoapplyaTTLlogicsignalwithproperwidththrough
thisportwhenconnectedtoanexternal(EXT)source.
2.5LOGIC/DVMPROBEJACK
Usedtoconnectthefurnishedlogicprobeforvoltage
andfrequencymeasurement(0.04Hzto35MHz)and
logiccircuitactivityanalysis.
2.6TRIPLEOUTPUTDCPOWERSUPPLYJACK
OntheMODEL4051,atripleoutputpowersupplyis
providedthroughfourbananasocketslocatedonthe
leftlowersideofthefrontpanel.OntheMODEL4050
specialconguration,thereisnotripleoutputpower
supplyandthefourbananasocketsarenotavailable.
2.6.1+VsJACK
Variablepositivesupplyoutputfrom0to+24Vwithtypical
outputcurrent1.5A.
2.6.2-VsJACK
Variablenegativesupplyoutputfrom0to–24Vwithtypical
outputcurrent1.5A.Thenegativesupplycanbeadjusted
independently,ortrackedwith+Vs(positive)supply.
2.6.3+5V/3.3V(VCC)JACK
Logicsupplyoutput5Vor3.3Vdependingonselectedmode
withtypicaloutputcurrentof5A.
2.6.4GNDJACK
Groundterminalforpowersupplyandsysteminputs/outputs.
2.7RESETSWITCH
Theresetswitchislocatedthroughapinholeonthe
frontpanel.Whenactivated,itresetstheMODEL4051
toitsfactorydefaultstate.Youshouldonlyresetyour
machineifanyofthefollowingconditionsoccurs:
•
Thevoltageofthegoldencapacitorhasdroppedbelow
1.8Vduetotheunitbeinginnon-operationstateforalong
periodoftimeandalldisplayandkeyswitchesarestuck
afterthepoweristurnedon.

Page14
FUNCTIONS
•Anypartofthedisplayandkeyswitchesarenotfunctioning
normallyduetostaticchargeorimproperoperation.
•Allprevioussettingsinthememoryleneedtobeerased.
Toreset,themachine,thepowermustbeturnedon.
InsertapapercliporpinthroughtheRESETpin-hole
andpushdownuntilthedisplayresets.
2.8POWERON/OFFSWITCH
Thepowerswitchislocatedonthelowerleftcornerof
thepanel,witharedLEDasthepowerindicator.
2.9LCD
5”x1.5”LiquidCrystalDisplaywithCCFLbacklight.
Inthedisplaycenter,thereisa6-digitindicatorusedto
show:
•
outputsignalforthefunctiongenerator
•
incomingsignalforthecounter
•
voltagemeasurementdisplaysfortheDigital
Voltmeter(DVM)
•
settingsforthetripleoutputDCpowersupply
Systemmessagesaredisplayedaroundthefour
edgesoftheLCDnearitscorrespondingfunction
key.Displayedsystemmessagesidentifythecurrent
operationandsettings.Whenadjustmentsaremade
usingtheDigitalEncoder,blinkingsignsindicatethe
settingsbeingaffected.
2.10RS-232CSERIALPORT
ADB9subfemaleconnectorislocatedontheback
paneltoallowtheusertoconnecttheunittoa
computerfor:
•
remotemonitoring
•
controlofsensorsoractivatorsincorrectiveoranalytical
applications
Thisconnectorconnectspin2toTXD,pin3toRXD,
pin5toground,andissetat9600bps1stop,8-bitno
paritymode.

Page15
FUNCTIONS
2.11VCGOUTPUT
TheBNCJackonthebackpanelisusedforvoltage
controlledgeneratoroutput.Theoutputvoltageis
proportionaltothegeneratorfrequency.
2.12HEATACTIVATEDCOOLINGFAN
Whentheambienttemperatureinsidetheunitreaches
adesignatedlevel,aheatsensingcoolingfanactivates.
Fanspeedwillincreaseordecreaseinresponsetothe
insidetemperature.Priortothefancomingon,it’s
normaltohearalowwhistlingnoisecomingfromthe
machine.(OntheMODEL4050machine,thefanis
poweredbyaconstantDCvoltageinsteadofaheat
sensingcircuit.)
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX [phone] - TestEquipmentDepot.com

Page17
OPERATION
SECTIONTHREE:OPERATION
3.1THEORYOFOPERATION
TheMODEL4051programmablemultifunction
Generatorisaversatilesignalsource,combining
fourcommonlabinstrumentsintoonelowcost,
userfriendly,andhighlyportableunit.Theheartof
thefunctiongeneratorisaVCG(Voltage-Controlled
Generator)thatproducesprecisionsine,squareor
trianglewavesoverthe0.2Hzto20MHzrange.A
builtinautorangingfrequencycounterdisplaysthe
outputfrequencyofthegenerator,orexternalsignals
fromthecounterinputorlogicprobe.
Coarseandnefrequencytuningcontrolspermit
precisionsettingoftheoutputfrequencywhichisthen
lockedwithin±0.2%bytheautofrequencylocking
functiontoeliminatedriftcausedbytemperature,
moistureorcomponentdegeneration.Acontinuously
variableDCoffsetallowstheoutputtobeinjected
directlyintocircuitsatthecorrectbiaslevel,andthe
variabledutycycleoftheoutputsignalconvertsthe
instrumenttoapulsegeneratorcapableofgenerating
rectangularwavesorpositiveornegativegoingpulses,
ramporsawtoothwaves,andslewedsinewaves.
Thesweepgeneratorcandigitizestartandstop
frequencieswithvariablesweeptimedisplayedin
linearorlogarithmicmode.Burstoperationenables
thegeneratoroutputtobecontrolledbyaninternalor
externalsignalwithasingleburstormultipleburstsof
apulsetrainatavariablewidthandtiming.Theoutput
canalsobeamplitudeorfrequencymodulatedbya
1KHzsinewaveinternallyorbyanexternalapplied
signal.
Digitaladjustmentsofactivequantitiesisperformed
bythedigitalencoderonupto18differentquantities.
Theactiveadjustmentdisplaysonthebargraph,
expandingtotherightwithincreasingquantitiesand
shrinkingtotheleftwithdecreasingquantities.Some
digitalvaluesmaybeconvertedintoanalogquantities
byadigitaltoanalog(D/A)converterforanalogcircuit
controls.
Electricalpowerforthesystemisdeliveredthrough
aswitchingACtoDCconverter.TheMODEL4051
hasthreeDCtoDCconverterstoprovideoutputand
protectionforthetripleoutputpowersupply.Each

Page18
OPERATION
supplycanbemonitoredbytheDVMwhilebeing
adjusted.Theauto-rangingDVMcanalsomeasure
theDCvoltageinputtedfromthelogicprobe.The
universallogicprobeisabletodisplayalllogicstates
insixuniqueformats.
Amemorybackupfeaturesavessettingsandallows
theMODEL4051toworksimilartoaconventional
mechanicalswitchoperatedinstrument,restoring
previousmodes,settings,andquantityadjustments
fromprevioususe.Uptotendifferentdatasetscanbe
storedtomemory,allowingforquickchangesbetween
differenttestingspecicationsfordifferenttesting
needs.Abuilt-inRS232Cserialporttothecomputer
enablestheusertoperformremotemonitoring,control
ofsensors,orcontrolofactuatorsincorrectiveor
analyticalapplications.
TheMODEL4051isaversatileinstrument,capable
ofprovidingavarietyofoutputwaveformand
functions.Togainaworkingfamiliaritywiththeunit,
itisrecommendedthatitbeconnectedinitiallytoan
oscilloscopesothattheeffectsofthevariouscontrols
ontheoutputwaveformcanbeobserved.
3.2BASICFUNCTIONGENERATOROPERATION
Pressingthe“ADJUST”keyatanytimeduring
functionoperationwillabortfromotherfunctions
andentertheBasicFunctionGeneratormode.In
thismode,frequencyandfrequencyrangewillbe
displayedontheLCDscreen.Asthedigitalencoder
isturned,theactivequantitybeingadjustedwillbe
identiedbyablinkingsign.
3.2.1COARSEFREQUENCYADJUSTMENT
Pressingthe“ADJUST”keyatanytimewillabortany
activeoperationsandenterintotheBasicFunction
GeneratorinCoarseFrequencyAdjustmentmodeand
theCOARSEFREQsignwillblinkontheLCDscreento
indicatethecurrentmode.Turningthedigitalencoder
clockwisewillincreasethefrequencyandturningit
counterclockwisewilldecreasethefrequencybylarge
units.Thebargraphwillalsogroworshrinktoindicate
thepercentageofthecurrentadjustedquantityatthis
range.Finefrequencyadjustmentscanbemadeby
pressingthe“ADJUST”keyagain.

Page19
OPERATION
3.2.2FINEFREQUENCYADJUSTMENT
Whenthe“ADJUST”keyispressed,thedefault
adjustmentmodeiscoarsefrequency.Pressing
the“ADJUST”keyasecondtimewillchangethe
adjustmentmodetonefrequency.Finefrequency
modeisindicatedbyablinkingFINEFREQsignon
theLCDscreen.Whenthedigitalencoderisturned
duringnefrequencymode,quantityadjustmentswill
increaseordecreasebysmallerunits.Toreturnto
coarsefrequencymode,pressthe“ADJUST”keyagain.
3.2.3FREQUENCYLOCKING
Afteradesiredfrequencyistunedbycoarseorne
frequencyadjustment,thefrequencylockingfunction
isautomaticallyactivated,holdingthevariationofthe
tunedfrequencywithin±0.2%.Thisfunctionisonly
availablewhenthe“COARSEFREQ”or“FINEFREQ”is
displayedabovethe“ADJUST”key.
NOTE:Wheneitherthe“COARSEFREQ”or“FINE
FREQ”issettomaxiumorminimumquantities,the
auto-frequencylockingfeaturemaynotfunction
properlyduetoinadequateadjustingrange.
3.2.4RANGINGSELECTION
Pressingthe“RNGUP”orthe“RNGDN”keyscan
instantlychangethefrequencybyadecade.Eight
availablerangescanbeselectedfrom2Hzto20MHz.
Tousethisfunction,selecttherangeandthenadjust
thefrequencybyusingthecoarseand/orne
frequencyadjustments.Outputfrequenciesfrom
0.15Hzto20MHzcanbepreciselyandrapidlyset.
Thefrequencydisplayinthe2Hzrangemaytakeextra
timetorespond.
3.2.5WAVEFORMSELECTION
Atanytimeexceptinfrequencycountermode,
pressingthe“WAVEFORM”keycanchangethe
outputwaveform—sine,square,andtriangle.The
correspondingwaveformappearssequentiallyeach
timethekeyispressed.


Page20
OPERATION
FIGURE3.1OutputWaveformandPhaseRelationship
3.2.6DUTYCYCLE(SYMMETRY)CONTROL
WhentheSYMkeyispressedwhileinbasicfunction
generatormode,themessage“DUTYCYCLE”will
blinkabovetheADJUSTkeytoindicateactivationof
dutycyclecontrols.Turningtheencoderclockwise
willincreasethedutycyclepercentage.Turningit
counterclockwisewilladjustthedutycyclepercentage
downward.Ifthedutycyclepercentageisabove50%,
aarrowwilldisplaynexttotheADJUSTkeyand
whenthedutycyclepercentageisbelow50%,a
willbedisplayed.Ifthedutycycleisatexactly50%,
noarrowswillbedisplayedaslongasthegenerator
outputsthesignal.
Pressingthe“CAL”keywillbringthesignalback
tosymmetryagainandthedutycyclearrowswill
disappear.Asthemaingeneratoroutputwaveformisa
squarewave,changingthedutycycleofthegenerator
willconvertitintorectangularwavesorpulses.For
atrianglewave,theresultisaramporsaw-tooth
waveform.Forasinewave,adistortedwaveshape
calledaslewedsineisproduced.TheMODEL4051
providesforsymmetryvariationfrom15%to85%.
TheTTL/CMOSlogicoutputhasthesamevariation
SINE0V
SQUARE0V
TRIANGLE0V
TTL0V
CMOS0V
aarrowwilldisplaynexttotheADJUSTkeyand
aarrowwilldisplaynexttotheADJUSTkeyand
aarrowwilldisplaynexttotheADJUSTkeyand
whenthedutycyclepercentageisbelow50%,a
whenthedutycyclepercentageisbelow50%,a
whenthedutycyclepercentageisbelow50%,a
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
FAX [phone] - TestEquipmentDepot.com

Page21
OPERATION
ratewhenthewaveformkeyissetforasquarewave.
Varyingthedutycyclewillresultinaslightchangein
frequency,whichcanbecorrectedbyadjustingthe
coarseornefrequencycontrols.
FIGURE3.2EffectofSymmetryVariation
3.2.7DCOFFSETCONTROL
ADCcomponentcanbeaddedtotheoutputsignal
bypushingtheOFFSETkey.WhenDCOffsetControl
isactivated,themessageDCOFFSETisashedon
thescreen.Theoffsetcomponentisadjustedusing
thedigitalencoder.Positiveadjustmentsaremade
byturningtheencodercounterclockwise,resulting
ina“+”messageandnegativeadjustmentsaremade
byturningtheencoderclockwise,resultingina“-“
messageaslongasthegeneratoroutputsthesignal.
Pressingthe“CAL”keywillrestoretheDCOffsetto
zeroandnosignwilldisplay.TheDCcomponent
introducedcanbevariedby±10Vasoutputinan
opencircuitor±5Vtoa50OHMloadtermination
whentheamplitudecontrolknobissettoMin.Ifthe
desiredoutputsignalislargeandclippingoccurs,an
oscilloscopeshouldbeusedtoobservethesignal.The
DCoffsetdoesnotaffecttheTTL/CMOSoutputJack.
Pulse
(Square)
Ramp
(Triangle)
Slewed
(Sine)

Page22
OPERATION
FIGURE3.3UseofDCOFFSETControl
3.2.8
OUTPUTLEVELAMPLITUDECONTROL
Theamplitudeleveloftheoutputsignalisadjusted
usingthe“Amplitude”controlknob.Rotatingthisknob
clockwisevariestheoutputamplitudefromminimum
to40dbaboveminimum.
Themaingeneratoroutputlevelis20Vp-pinto
anopencircuitand10Vp-pintoa50OHMload
termination.TheoutputleveloftheTTL/CMOSoutput
jacksisindependentoftheOutputLevelAmplitude
Controlknob.
3.3SWEEPOPERATION
TheSweepfunctionoftheMODEL4051provides
automaticvariationoftheoutputfrequency.From
astartingsettingtoadesignatedstopsetting,the
frequencycanbeincreasedordecreasedinalinear
orlogarithmicformat.Beforeenteringthesweep
operation,selectthewaveformandmakeadjustments
tothefrequency,amplitude,dutycycle,andDC
offsetoftheoutputsignalasdescribedpreviously.To
performaSweepOperation,presstheSWEEPkey
whileinBasicFunctionGeneratormode.Thedisplay
Positive
DCOffset
Negative
DCOffset
Positive
DCOffset
Negative
DCOffset
1.ZeroDCOffset
1.ZeroDCOffset
withMaximum
withMaximum
Signal
2.OffsetLimits
Without
Clipping
3.ExcessiveOffset
3.ExcessiveOffset

Page23
OPERATION
shouldshowthesign“LIN”undertheSWEEPkeyand
”INT”undertheSOURCEkey.
•Totogglebetweenlinear(LIN)andlogarithmic(LOG)modes,
presstheSWEEPkey.
•TotogglebetweenInternal(INT)orExternal(EXT)controlsignal
source,presstheSOURCEkey.
Note:
DuringtheSweepoperationorafterSweepmodeisselected,
somekeyswitchesaredisabled.Toabortthefunctionandreturnto
BasicFunctionGeneratormode,presstheSWEEPorADJUSTkey.
Thefrequencyvariationpaceisdeterminedbythe
initialselectionofLINEARorLOGARITHMIC.Ifthe
sweepmodefrequencyrangeorfrequencypoints
needadjustment,presstheSETkeytostopthesweep
operationandreturntotheoriginalsetupprocedureto
modifytheoperationasdesired.Ifthestartfrequency
selectedislowerthanthestopfrequency,thefrequency
sweepisincreasedfromlowtohigh,otherwise,the
frequencysweepisdecreasedfromhightolow.
ToperformaSweepoperationusinginternalcontrolsignalsource:
•MakesurethesignalsourceissettoINT.PresstheSOURCE
buttontotoggle.
•Pressthe“SET”keytostrobetheselection.
•The“START”messagewillblinktopromptforadesiredstarting
frequency.
•Adjusttheencoder,therangingkeys,andthenpressthe“SET”
keyagaintostrobethestartingpoint.

•Whenthe“STOP”signashes,turntheencodertoselectthe
endingfrequency.
•Pressthe“SET”keytostrobetheselection.
•TheSweepOperationstartsandthedisplayashesstartfrequency
andstopfrequencyandblinksthe“TIME”sign.
•Turntheencodertoadjustthesweepingtimefrom“START”to
“STOP”.Whilethedigitalencoderisbeingturned,thesweep
operationwilltemporarilystop.
ToperformaSweepoperationusingexternalcontrolsignalsource:
•MakesurethatthesignalsourceissettoEXT.PresstheSOURCE
buttontotoggle.
•PresstheSETkey.“EXT”and“COARSEFREQ”willashonthe
displaytoindicatethatthe4051isreadyforanexternalsignal.
•Usetheencodertoadjustthestartingfrequency.
•PluginanexternalcontrolvoltagesourcetotheVCG/MODBNC