Download - ADC1 Manual Final

7/29/2019 ADC1 Manual Final

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RichardHaberkamp

NikolasRoosevelt

APracticalExercisefortheADC

JanuszZalewski,Ph.D

CDA4170,DataAcquisition&Control

Spring2009


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TableofContents

1. EquipmentConnectivity 31.1RequiredHardware 3

1.2Hardware

Interfaces

3

2. SystemSoftware 42.1RequiredSoftware 4

2.2RunningLabVIEW 4

2.3ConfiguringLabVIEW 6

3. Application 63.1OpeningADCVI 6

3.2Configuring

ADC

VI

7

3.3ADCCommands 9

4. References 115. Appendix 12


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1. EquipmentConnectivity1.1RequiredHardware

Thefollowingcomponentsareneededforthisexercise(SeeFigure1):

SuperLogicsADC1[1] SomedevicetointerfacewiththeADC1(suchasabatterypack) Computer,suchasaPCorLaptop,whichmusthaveanavailableserialporttointerface

withtheSuperlogicsADC1andmustalsomeettheminimumrequirementsofLabVIEWas

detailedinTable1.

Table1:LabVIEWSystemRequirements[2]


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1.2HardwareInterfaces

Toproperlysetuptheequipmentforthisexercise,theuserisrequiredtoconnectthe

componentsas

shown

in

Figure1:

Figure1:HardwareSetup

2. SystemSoftwareToperformthisexercise,theuserisexpectedtohaveNationalInstrumentsLabVIEW8.6

alreadyinstalledontheircomputer.

ToruntheLabVIEWapplication,theusercanfollowthesesteps:

Step1:LeftclickontheStartmenubutton(seeFigure2).

BatteryPack

Computer

SuperLogicsADC1

ElectricalOutlet

PowerSupply

Serial(RS232)

Connection


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Figure2:StartMenuButton

Step2:NavigatethroughtheStartmenu.ThedefaultStartmenupathoftheapplicationis

Programs >NationalInstruments >LabVIEW8.6 >LabVIEW,asshowninFigure3.

Figure3:LocatingLabVIEWintheStartMenu


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Step3:Afterthesplashscreen,youwillbepresentedwiththemaindialogofLabVIEW,asshownin

Figure4.

Figure4:MainLabVIEWWindow

ThisexercisewillusethedefaultconfigurationoftheLabVIEWapplication.

3. Application3.1OpeningADCVI

1

AftertheuserhasopenedLabVIEW,theycanthenopentheVIusedtocommunicatewiththe

ADC.ItisassumedthattheuserhasacopyoftheVIavailableontheircomputer.Thefollowing

stepsdetailhowtoopentheVI(assumingitislocatedontheirdesktop):

Step1:FromthemainwindowselectFile >Open(AsshowninFigure5)

Figure5:HowtoOpentheVI

1 LabVIEW programs are commonly called Virtual Instruments, in brief VIs


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Step2:AfterbeingpresentedwiththeOpendialog,navigatetothelocationwheretheVIis

savedbyleftclickingtheDesktopbuttonintheleftpane(seeFigure6).

Figure6:LabVIEWOpenDialog

Step3:Leftclickonthenameofthefile,such ADC1RW.viandthenleftclickontheOK

button(SeeFigure7). Asaresult,theapplicationwillopeninawindowasshowninFigure8.

Figure7:SelectingtheFile

3.2ConfiguringADCVI


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TheVIiswrittentocommunicatewiththeADCviatheserialportviathedefaultconfiguration.

Theconfigurableparametersareasfollows:VISAresourcename(port),baudrate,databits,

paritybit,stopbits,andflowcontrol.Intheeventthatanerrorisencounteredwhiletryingto

communicatewiththeADC,theusermayneedtotweakthesesettingsfromthedefaults.

Thedefault

configuration

is:

VISAresourcename:COM1 baudrate:19200 databits:8 parity:None stopbits:1.0 flowcontrol:None

Figure8:ADC1RW.viFrontPanel

Onceanynecessaryconfigurationchangeshavebeenmade,theusermustleftclicktheRun

Continuouslybutton.


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Figure9:LeftclicktheSecondButtonforRunContinuously

WhiletheVIisrunning,theusermaytogglethewriteandreadswitchestotheONposition.This

willallowtheVItowritetheuserspecifiedinputtotheADC,andthenreadanyvaluethatmaybe

returned.Asuccessfulcommunicationofthedefaultstringtowritevalueof*IDN?\r\nwillprovide

aread

string

of

X

(as

shown

below).

Figure10:ASuccessfulWritethenRead

3.3ADCCommands

Providedfortheuseristheabilitytousepreprogrammedcommandsinsteadofthosethatare

userspecified.Theusermayselectonepreprogrammedcommandsbyselectingadifferent

optionunderInputSelection.Therearefourpreprogrammedcommandsavailabletotheuser:FirmwareVersion,DigitalInputPortStatus,PulseCounter,andReceiveErrorCount.ThereareadditionalcommandsthattheusermayissuewiththeUserInputoptionselected.Eachcommandspecifiedinthestringtowritefieldmustbefollowedby\r\n.Thisissuesacarriagereturnandnewlinewithinthewritestring,andisrequiredforsuccessfullyissuingcommands.

Additionalcommandstheusermayspecifyareasfollows:


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Table2:ADCCommand/Response Table[3]

Note:AnexceptiontothislististheLyxxx(D/Aoutput)command.Thistableisfromthe

equipmentmanualthataccompaniestheSuperLogicsADC1R2,whichisbaseduponfirmware

version3.0.UsedinthisexerciseistheolderADC1modelwhichusesfirmwareversion2.2.Using

theLyxxxcommandwiththeoldfirmwarewillprovidearesponseofX.


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3.4ReceivingDataFromTheADC

Usingthefollowingtableinconjunctionwitheitheroftheanalognibblecommands,UorQ,theuser

cantakereadingsfromeachoftheanalogchannels. Theusercanreaddirectlyfromaport,ortake

thedifferentialbetweenchannels.

Table3:AnalogControlNibbles[3]

Table4:ExampleNibbleCommands[3]


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[1]SuperLogics,RS232DataAcquisitionDevice,SuperLogics,Inc.,Waltham,MA,2002,

http://www.superlogics.com/specpage.asp?Items=8000

[2]NationalInstruments,SystemRequirementsforLabVIEWDevelopmentSystemandLabVIEW

Modules,NationalInstrumentsCorporation,Austin,TX,2009,

http://www.ni.com/labview/requirements.htm

[3]SuperLogics,ADC1R2I/OModuleManual,SuperLogics,Inc.,Waltham,MA,December30,

2004,http://www.superlogics.com/manuals/adc1.pdf


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5.Appendix:DevelopmentoftheADC1VirtualInstrument

ThefirstthingthatneedstobedoneistodownloadandinstallthemostcurrentNational

InstrumentsDeviceDriversfromni.com. Afterthishasbeencompleted(downloadingand

installingnormallyrequiresonetotwohours)developmentoftheVIinLabVIEWcanbegin.

ThewaytogoaboutdevelopingthisVIistobreakitupintosmallercomponents. First,

establishcommunicationswiththedevice. Then,addtheabilitytoinputcommandsand

receivearesponse. Next,addsomefunctionalitysuchasbuttonsforcommoncommands,

comboboxeswithconfigurationoptions. Finely,addthecomponentstoreadinvoltages

fromtheADCanddisplayitnumericallyandasagraph.

5.1Establishing

Communications

with

the

Superlogics

ADC

1

Tobeginprogramming,openLabVIEWfollowingthestepsoutlinedinsection2ofthis

document,SystemSoftware. Oncethisisdone,doubleclickonBlankVI(showninFigure11)

tocreateanewLabVIEWproject.

Figure11:OpeningablankVI

ThefrontpanelofanewVIwillopen. InordertocommuicatewiththeADC,weneedsome

waytoconfigureourVItocommunicatewithit. Luckelly,LabVIEWcomesprepackagedwith


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severalInstrumentI/OVIs. TheVIswewillmostlybeusingaretheVISAs locatedinthe

IntrumentI/Opalletteofthecontrolpanel,asshowninFigure12.

Figure12:ControlPanelshowingexpandedInstrumentI/Opalette.

Toallow

communication

between

the

ADC

and

the

application,

the

user

will

have

to

be

able

tosettheproperportconfiguration. Todothis,clickanddragtheVISAConfigureSerialPort

formtheInstrumentI/OunderSerial. DragtheVISAanddropitontotheblockdiagram

(Figure13).


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Figure13:PlacingtheVistaConfigureSerialPortontheBlockDiagram.

ThisVISAallowstheportsettingstobeestablished,eitherbyconstantssetbythe

programmer,orasinputsfromtheuser. Theusershouldbeabletochoosetheproper

settings,so

the

next

step

is

to

add

controls

for

the

proper

port

settings.

To

add

each

of

the

controlsrightclickonthefrontpanelanddraganddropaTextControl(Figure14)foreachof

therequiredsettings:PortName,BaudRate,DataBits,Parity,StopBits,FlowControl,and

ReadFrequencyasshowninFigure15.


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Figure14:TestControls

Figure15:PortSettings.

WireeachcontroltotheVISAConfigureSerialPortasshowninFigure16.


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Figure16:WirecontrolstoVISA.

CommandInput

NowwewanttobeabletoinputcommandstotheADC1. Thiswillrequirecontrolsto

selectdesiredcommands,andaswitchtowritetotheADC. AddaswitchtotheFrontpanel

inthesamemannerasaddingtextcontrolsinsection5.1asshowninfigure17.

Figure17:SwitchControlPalette

ThiswillbetheWritecontrol. AddaCasestructuretothebackpanelfromtheProgramming

PaletteasshowninFigure18andFigure19. ThiscasewillbetruewhentheWriteswitchis


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toggledonandfalsewhenitistoggledoff.

Figure18: TheProgrammingPalette.

Figure19: Casestructurewithwritetogglewired.

InsidetheWritecasestructureisanothercasestructure. Thisonehasadifferentcasefor

eachofthecommandoptions. SelectanothercasestructurefromtheProgrammingPalette


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andplaceitinsidetheWritecasestructureasshowninFigure19.

SelecttheVISAWriteobjectfromtheI/OpaletteasshownpreviouslyinFigure12anddrop

ininsidetheinnercasestructure. ThiswillallowstringstobewrittentotheADC. Labelthis

caseas

User

Input,

and

make

it

the

default

case.

This

will

be

for

when

the

user

whishes

to

inputacommandthatisnotincludedwiththisapplicationcommands. AddaTextControlto

theinsideofthiscase,andwireittothecase. Addanothercasetotheinnercasestructure

andfollowtheabovestepforeachcommandyouwishtohaveincludedwiththeapplication.

NowtheVISAConfigureSerialPortneedstobewiredtotheVISAWriteasshowninFigure

20. NowtheapplicationcanwritetotheADC.

Figure20: WiretheConfigureSerialPorttotheVISAWrite.

ReadingFromTheADC1

ThissectioncoversreadingfromtheADC. Youwillneedawayofcontrollingthefrequency

atwhichtheADCispolled. ThiscanbedonewithaStackedSequenceStructurefoundinthe

ProgrammingPaletteasshowninFigure18. AddonetotheBlockDiagram. Insidethis,

placeaNumericalControlwiredtoaWaitcounterfoundintheTimingPaletteunder

Programming(Figure21).


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Figure21:TimingPaletteandFrequencyControl.

NowcreatetheCaseStructuretocontrolwhentoreadfromtheADC. PlaceanewCase

StructureontheBlockDiagramandaddaReadToggleSwitchaswasdonefortheWriteCase


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Structure. SelecttheVISAReadfromtheI/OPaletteasshowninFigure12. Alsoadda

PropertyNodeinsidethisCase. NowtheVISAWritefromSection5.2iswiredthroughthe

FrequencystructuretothePropertyNode,andthentotheVisaRead(Figure22).

Figure22:Write,ReadandFrequencyControl.

CreateaText

Indicator

and

wire

it

to

the

VISA

Read.

This

shows

the

output

of

the

ADC.

CreatingtheGraph

Tocreatethegraph,selectBuildXYGraphfromtheExpressVIspalette. Placeitontheblock

diagramasshowninFigure22. SincetheVISAReadoutputsastring,thisoutputwillhaveto

beconvertedtoadoubletobereadablebythegraphfunction. TodothisweuseaString

Subsetfunctiontoreadonly3charactersofthestring,thenconvertthatstringintoanumber

usingaHexadecimaltoNumberfunction. BothofthesearefoundintheProgramming

Palette. PlacetheseontotheBlockDiagramandwirethemtogetherasshowninFigure23.


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Figure23:TheReadCaseStructure.

TheoutputthenneedstobeconvertedtoadoublewiththeToDoublePrecisionFloat

function. ThesignalisthendividedbyaconversionfactorandwiredtotheYinputofthe

BuildXYGraphVIasshowninFigure23. TheBuildXYGraphisthenwiredtoanXYGraph

indicatorwhichisplacedontheFrontPanelasShowninFigure24. NowtheApplicationis

readytoberun.

Figure24:TheCompletedApplication