Software advances in measurement and instrumentation

October 1994 OCR Output

SOSO@C€l‘l1VHl.C€l°ll.Ch

Fabio Soso, CERN·CN/CE

presentation.

eral-purpose data-acquisition, data analysis, and intuitive, graphical dataputers (PCs) and workstations with sophisticate sojiware that integrates gen

Today’s data acquisition and instrument control systems combine personal comAbstract:

LabVIEW

ment and Instrumentation.

Software Advances in Measure

CERN-CN-94-10

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useful, particularly about early years, and worded out better thaninteresting, book on LabVIEW. Information therein was veryAcknowledgement: I‘m indebted to Gary Johnson for his new,

10 — Slides

Annex

Conclusion

Characteristics of LabVIEW

Development of LabVIEW

The ideal software

Structure of programs for instrumentation controlElecuonic instrumentation todayPlaying with a Bouncing CubeSubject of thc talk

INDEX

LabVIEWCERN/CN/F S /94

l. Laboratory Virtual Instrument Engineering Workbench OCR Output

Let us play with a Bouncing Cube (Fig 2.1).

stration.

we will start with an amusing (yet instr·uctive) LabVIEW demonstanding, risk to be slightly boring. Hence to keep interest alive,The introductory parts, although useful for the general under

gramming languages.and the software too can be different from the traditional pronot instruments any more - we’ll call them "virtual instruments"In fact, the situation is so fluid, that we'l1 see that instruments are

includes quite a variety of tasks and solutions.(b), software for instrumentation control; this generic term

the user with an apparently chaotic set of choices.(a) electronic instrumentation: it evolves rapidly, presenting

control, we must consider two introductory subjects:

To evaluate LabVIEW in its natural context of instrumentation

ming language, of anew kind, makes it an interesting topic.gramming languages. The fact that LabVIEW is a real programperformance penalty when compared with conventional prodebugger. It has few intrinsic limitations, and only a minimalextensive libraries of functions and an integral compiler anda purely graphic, general purpose programming language, withFortunately, LabVIEW is more than a specialized application: it's

tromc instrumentation.

Instruments Corporation of Austin, Texas, for the control of elecI wish to present LabVIEW‘, a program developed by National

1 - SUBJECT OF THE TALK

LabVIEWCERN/CN/FS/94

(Fig. 3.1). OCR Outputcomputer, which has become the core of a measuring systemcomplex, more or less costly, but never disconnected from aToday, we can use various types of instruments, more or less

by a single plug-in board, inside the computer.For simple applications, the whole instrument could be replaced

the computer screen.buttons, replaced by graphic windows with operating menus onThe instruments began to change, some front panels lost their

instrument to the controlling computer.Control and data acquisition tasks shifted from the comrolled

ments increased as well, and so did the number of users.most instruments, the benefits of connecting PC's to instrucomputers surpassed the intemal processing capability of

(2) The PC revolution. As the processing power of desktop

tional standard, ref. IEEE 488, and is still in full use.of groups of instruments; GPIB soon became an intemaInstrumentation Bus (GPIB) for the connection and control

(l) The definition, by Hewlett Packard, of a General Purpose

Two events marked this time:

bit of extra flexibility adding to the cost.instruments were still those defined by the manufacturer, everyby off-line data processing. The functional characteristics ofequipped with a teletype terminal. Data recording was followedsome instruments had a special connection to a small computerrecording used printers, paper tape punches, mag tape drives;

tion of numerical functions. Semi—automatic measurementIn the 80's, instruments became more sophisticate with the addi

cil&paper, Polaroid cameras, occasionally a chart recorder).The recording of measurement was essentially manual (pen

nor the instrument built-in functions.

panel; the user couldn't modify the type and number of controls,scopes, were controlled by knobs, switches, displays on the frontmultimeters, sinewave/pulse generators, fast or slow oscilloIn the 70's, instruments were mostly "analog". Power supplies,

3 - ELECTRONIC INSTRUMENTATION

LabVIEWOCR OutputCERN/CN/FS/94

reduced to the bare minimum, every control and display OCR Outputand Fastbus in physics experiments. The front panel isof a standard chassis; types include VME or VXI, Camac

(3) Modular instruments (Slides 5b to 7a), i.e. plug in modules

replicated on the computer screen.the GPIB bus, or via a serial port. The front panel can beinstruments (Slide 2a,2b) are connected to a computer viameters, frequency synthesizers, logic analyzers, etc.). Theprocessing capabilities (digital oscilloscopes, digital multiwith crowded front panels, intemal memory and signal

(2) Traditional style instruments, often performing and costly,

instrumentation control.

(1) A PC or a workstation, with some interactive software for

Schcmatically, wc may find:

Figure 3.1 Instrumentation Control System

EQUIPMENTMONITORUU-r _ SIGNALS TO

INDUSTRIAUOTHER

I L I SRS232

BOARDSDAQ

GPIB I/F E·NET PORT

WorkstatlonPC or ·

compuransBUSBUS TO OTHERVME I MXIVXI/I MXI

INSTRUMENTS VMEGPIB

CAMAC

FASTBUSVXI


shown by PCMCIA data acquisition and interface boards for OCR OutputAnother trend, towards miniature, portable control systems, is

home, via a modem, or anywhere in the world with Ethemet.Operators can also control and monitor tests and review data at

check the performance of a device under test.any group of instruments via the GPIB/ENET interface and toout leaving their desk, can use their workstations to connect toIn this multitasking environment, the company engineers, with

16 test instruments.

system can control up to 32 test benches, each containing up tocigarette box, and Tektronics TDS series oscilloscopes, the fullBy using Sun Sparcstations, GPIB/ENET interfaces the size of a

duced part.collect data in a useful format for the final report of each proThe control system is used to set up instruments, initiate tasks,

tors.

by an Australian manufacturer of implanted cardiac defibrillashows a distributed measurement and control system developedThe future will bring us new features. Fig 3.2, for instance,

developers.supported by LabVIEW drivers available from 3rd-partythey use proprietary series protocols, many of which aretrollers for industrial equipment. Used in physical plants,able low speed analogue and digital I/O interfaces and con

(5) Programmable Logic Controllers (PLC's), robust and reli

nique when measuring many signals.linearize, isolate, filter. Also multiplexing is a useful techducer electrical signals to the DAQ boards input: amplify,Signal conditioning modules are used to adapt the u·anssophisticate measurements).one (whereas VXI and GPIB instruments are used for moreules makes the choice of plug-in DAQ boards a popularDigital converter circuits and of signal conditioning modcomputers (Slides 3a to 5a). The evolution of Analog to

(4) Plug-in data acquisition boards for the various types of

boards)programs, Plug&PLay for VXI modules and plug-inments (SCPI standard commands for instrumentationing to define universal routines for the control of instru

Moreover, the various instruments manufacturers are striv

user's needs and modified at any time.memory, the use of local intelligence can be tailored to the

choice of functions, the number of channels, the amount ofsmaller, easier to test and develop, user-configured: thebeing provided by the computer. Modular instruments are


Fi ure 3.2 A distributed Instrument Control S stem 8 OCR Output

ca:ntestICDs without Ieavingtherrdesks, orn anywhereint}iew0ridvihEd1emet.By integrating the GPIB·ENET interface kit into the ICD test and measurement system, Telectronics oper.

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with an exuemely low power consumption and the size of athe same performances of their full scale correspondents, butnotebook and Laptop computers (Slide Bo). These boards have


grated with the other types of operation. OCR Outputtem (e. g. they are part of LabVIEW), even better if they are inteHowever they are part of a well organized data acquisition sysare not mandatory parts of an instrumentation control software.Data analysis, data presentation and storage, data transmission,

user, authorisation protections, etc.dependent decisions, the time scale, provide interaction with theinstruments setting and calibration, the measure sequence, dataThe managing program (e.g. LabVIEW) must supervise the

the insuument.

access a high level function, or get up to a particular register ofthrough a replica of the front panel. The user can choose torelevant features of each instrument, seen as one device, e. g.Instrument drivers (e.g. within LabVIEW) allow to address the

the computer operating system to talk to the I/F boards.form-specific, plug-in interface board. Low level drivers allowEach type of instrument is linked to the computer by a plat

DAQ's (data acquisition boards), industrial controls.data, by various types of instruments: stand alone, modular,The electrical signals are measured, i.e. converted to numerical

nals conditioners/multiplexers when required.electrical signals by transducers/actuators, with the help of sig(From bottom to top). Physical parameters are transformed into

software.

test&measuring system, including the various parts of the controlFig. 4.1 gives a schematic view of a computer controlled

INSTRUMENTATION CONTROL

4 - STRUCTURE OF PROGRAMS FOR


10 OCR Output

Figure 4.1 Structure of Software for Instrumentation Control

PHYSICAL PARAMETERS TO BE MEASURED/CONTROLLED

ELECTRICAL TRANSDUCERS - DETECTORS · ACTUATORS

MODULES ERS

FASTBUS I IMULTIPLEX(PLC’S)MENTS I CAMACN ME- I ERS

|NSTRU· ULES CONDITION- CONTROLS QTRADITIONAL I VXI MOD- I SIGNAL I INDUSTRIAL I E

BOARD I I/FACE I BOARD I PORT I I/OGPIB I/F I VMENXI I DAQ I RS·232 I DIGITAL

DRIVER I DRIVER I DRIVER I DRIVER I DRIVERNI·GPIB I NI·VXI I N|·DAQ I SERIAL I NI-DAO

OPERATING SYSTEM (DOS, MAC-OS, SUN-OS, ETC)

WINDOWS 3.1, WINDOWS NT, ETC

D. Q".INSTRUMENT DRIVERS (ONE/INSTRUMENT)

MANAGING PROGRAM (LABVIEW)

SIGNAL ANALYSIS

TATIONDATA PRESEN· | DATA STOR- CONNECT TO EAGE/OUTPUT I NETWORKS l gf


11 OCR Output

canons.

from the others, and sharing it between different users and applitally. Time is gained by developing each module independentlymodules, connected either vertically (hierarchically) or horizonIt is necessary to split complex programs into any number of

Modular

levels.

using the same programming method and user interface at allHomogeneous

apply, customizable.i.e. use a graphical user interface intuitive in operation, simple to

GUI based

the real job of measuring and interpreting data.aphors, compiling and linking commands, etc. is subtracted fromprogrammers. 'lime spent in learning syntactical subtleties, metto use, and to program. At its best, it should be a software for non

Easy to learn

age level.needed to bring data through the analysis, presentation and storthe high level (instrument) drivers; and provide all the functionsboards and communication ports), for all the operating systems;ious categories of instruments (GPIB, VXI, Camac, VME, DAQfunctions shown in Fig. 4.1, viz. the low level drivers for the varcost development time. The ideal software should include all theUsing different types of software fro the same application can

Comprehensive

According to my list, the software should be:

row.

and running, controlled at the screen of our computer, by tomoravailable, we can endeavour to have the whole thing configuredmaterials today, and we have our Macintosh, PC or WorkstationSo ideal, for instance, that if we receive all our instruments and

"ideal software for instrumentation control"that we are going to use, and list on paper our definition of theto have a measuring task, knowing more or less the instrumentsLooking back at Fig. 4.1, we could do a little exercise: imagine

5 - THE IDEAL SOFTWARE


12 OCR Output

instruments miss their drivers. But overall, the goal is attained.by the company (butter on their bread), and some commercialTruly, the low level drivers exist only for the materials proposed

prietary product.requirements that we have ideally listed, except one - it’s a proSince the end of 1993, anyway, the program fulfils all the

interesting in itself, and worth telling.bring it to completion. The story of LabVIEW development isto start a project, and keep it alive for the long time that it took tosame exercise. The difference is that they were enough visionary

,_ then small company (National Instmments), sat down to do thecan better appreciate the fact that a decade ago some people, in aHaving thus deiined the ideal software for our application, we

tional norm.

be vendor independent, and possibly labelled with an interna

Standard

do a program. Upwards compatibility is essential.developments and collected data must last for years. So should

Stable

cases, without names).It makes a difference whether it costs 2000$ or 3000O$ (real

Cheap

becomes quickly useless.A program which limits the size, type or speed of applications

Powerful

tolerate also slow programs.PC's and alike are slow enough, when used with instruments, to

Fast

data acquisition program, presentation).any user, at any time, and any stage (instrument configuration,Only if a program is self documenting, it allows modifications by

Easy to maintain/modify

Obviously

Interactive

ObviouslyEasy to debug

table w/o modifications.Sun, others). Better, every application developed should be porThe software should be the same on every platform (PC, Mac,

Portable

LabvnawCERN/CN/FS/94

13 OCR Output

l. Remember... (beep) SYNTAX ERROR AT LINE 3457

refrigerator and a microwave oven. There were no windows andtheir graphics capabilities, 10 young people out of school, athey brought in ten small Macintosh (512K memory) chosen forloft, away from the company but near the university of Austin;With these ideas in mind, J.K. and a few others hired a 80 sqm

grammmg

graphic form. Hence the name of "structured data flow prostructures like loops and iterations were added in a specialsen, to simulate real systems, and some programmingdata transmission. A data-flow- based operation was choresent the functions, and electric-like wires to symbolizetranslating it into a design tool, using labelled icons to repvisualize the problem and suggests a design. Why notproject, draw as the first thing a block diagram. It helps to

b) A graphic programming method. Designers who start a

had to be a facsimile of a real instrument front panel.

with it Hence the most familiar and intuitive user interface

instrument by studying its front panel and experimentinga) A graphic user interface. Most engineers leam about an

were:

But what form a new language should take? The original ideas

would make the computer accessible to non-programming users.decided that only a new tool for developing instrument softwareIn April 1983 Jeff Kodosky and other cofounders of Nat.Inst.

the programming burden placed on engineers.develop tools for the control of instrumentation, was sensitive toNat.Inst. which had its own team of programmers struggling to

lutely necessary.result, data acquisition was automated only when it was absousers were discouraged by arcane syntax and messages‘. As aUsers with little or no programming experience, or occasional

tasks.

into long and tedious line programs, even for simple measuringprogrammers, i.e. to translate the knowledge of their applicationsguage it required scientists, engineers and technicians to becometive capabilities, but like any other text based programming lanBASIC had a simple and reusable set of commands, and interac

ments (via GPIB bus), were written in BASIC.Most programs for the first generation of PC-controlled instru

6 - THE DEVELOPMENT OF LABVIEW


14 OCR Output

forms — and such will hopefully remain.founders. The applications (VI's) are fully portable between platarchitecture was unified, according to the original idea of theOnly at the end of 1993 (ten years laterl), with version 3.0, the

were not compatible.the same program to a Macintosh or a PC user, the two versionsager') layer had been redesigned. Although they would appearplatforms. Once more, most of the machine dependent ('manIn Aug. 1992 LabVIEW ver. 2.5 would run also on PC and Sun

tecture, and to produce LabVIEW for other platforms.tems, N at.Inst. decided to give LabVIEW a new portable archiIn the following years, with the appearance of new operating sys

boards for PC`s.

ciation, while other companies were mostly producing plug-instarted to produce plug-in boards for the Mac + LabVIEW assoBy luck, the Mac H had an open architecture, and so Nat.Inst.

tion; Vlhndows 3 had still to come.addressing support necessary to a large, sophisticated applicaPCs and DOS still lacked the graphics capability and the 32-bitneers and originally intended only for prototyping. At that time,It was running only on Macintosh, a platform unfamiliar to engi

interpreted version.compiled version was as flexible and interactive as the previousture, an almost instantaneous integral compiler. For the user theincorporated Object Oriented Programming and, as a new feamany user remarks. When version 2.0 was shipped, it was fast, itIn 1990 LabVIEW was fully rewritten, taking also into account

unfortunately required a complete redesign!applications. The only solution was to make it compiled, but thatrobust, proving the original idea good, but still too slow for largeIn 1987 came version 1.2; now the program was reliable and

defective.

the program was slow even compared to interpreted Basic, andthree years later, they had to release version 1.0 for Macintosh,mated, the machines available had many limitations, etc. When,ble product was less easy. The task had been largely underestiThe early development went on very quickly, but getting to a via

rupted by sudden, collective discussions on interesting topics.no visible clock; work would most often go on ovemight, inter


rs OCR Output

ware. The VI concept is so fundamental to the way thatchart recorder), thus increasing the versatility of available hard(e.g. a voltmeter) into another, software based instrument (e. g. aLabVIEW; it allows for instance to transform a real instrumentThe concept of virtual instrument (VI) has been pioneered by

VIs

panels are adapted also to unskilled users.to customize, and nice to look at. Control panels that mimic reallevels of hierarchy; it's intuitive in operation, simple to apply andThe LabVIEW built-in graphic user interface is the same for allGraphic interaction is generally preferred to textual interaction.

Graphic User Interface (GUI)

inter-platform portability

communication/storage tools

data presentation libraries

data analysis libraries

instrument drivers

modularity and homogeneity ___J_

integral compiler

datailow execution

graphic programming method, self documenting

. I graphic user interface

The features that we want to point out are the following:

ideal software for instrumentation control.

developer's and the user's task, and which make LabVIEW theLabVEW features that go in the direction of facilitating both theBy working with a few LabVIEW examples we will examine the

increasing complexity.structure, are vital in controlling the cost of test programs ofreusability, intrinsic in LabVIEW hierarchical and homogeneousopers are the answer. Software modularity, maintainability andming tools which reduce the effort of individual software devel(and Mndows 3) to be accepted. New, user·f1·iend1y programThis axiom, today conventional wisdom, has taken a few years"Thc uscr's time is more valuable than the deve10pers' time"

7 - LABVIEW FEATURES

LabvmwCERN/CN/FS/94

is OCR Output

cation builder.

Run-time version of LabVIEW or as executables, with the applias interpreted ones. One can also create applications for thecompiler is fast and invisible, and the programs are as interactivethat of C-compiled programs. From the user's point of view, themachine-optimized code, executable at a speed comparable toLabVIEW includes a graphic compiler which generates a

Fast Compiler

neously.LabVIEW several paths can be created and executed simultafrom the linear (sequential) structure of textual languages. Inobjects which controls the execution. This method makes freethe object has executed. It is the data flow between connectedpresent. The same way, the object outputs cannot be used untilming, an object cannot be executed until all its input data areprogramming. and data iiow execution. Vsdth data How programLabVIEW programming is based on modern Object Oriented

Dataflow Execution

character, favour the development of large projects.The precise method of producing VIs, and their self documenting

ies, either supplied with LabVIEW, or developed by users.High level operations are encapsulated in convenient VI librar

enclosed in a textual structure.

placed within structures in the same way as code lines areCase instructions, with all the corresponding tools. Icons aresic, textual languages: For loops, While loops, Sequence andThe LabVIEW programming structures are the same as in clas

data types, programming structures and a sophisticated compiler.tool — it's a true programming language complete with multipleLabVIEW iconic programming is not simply an organizational

tem.

there is no underlying procedural language or menu-driven sysof icons and wires, which directly couple to executable code;LabVIEW programming is done via a block diagram, consisting

Graphical Programming

maintain.

and combined. In addition, VI's are easy to understand and tolevel or top level functions, and can be modified, interchangedules. All VI's follow the same rules, whether they describe lowments, like high performance ADC plug-in boards or VXI modInstruments areparticularly useful when using panel-less instruLabVIEW works, that programs are in fact called Vls. Virtual


17 OCR Output

In the past, data were presented through text based interfaces,

their data presentation.grammers. Many data acquisition system are only as good astion, it’s an often neglected, yet time consuming task for proData presentation is the final element of a complete data acquisi

Data Presentation

operations, integral/derivative, and pulse/threshold detection.lation, DSP, digital filters, smoothing windows, statistics, arrayfunctions fall into several major groups: signal generation/simuLabVIEW contains more than 170 analysis functions. These

uons.

is needed, as data iiow smoothly between the various applicaNo special data fonnatting, or use of other proprietary software

sis Vls.

LabVIEW, appears when acquired have to be fed into the analyThe real benefit of virtual instruments, and the power of

Data Analysis

Re-configurable instruments are more flexible.modifiable according to the developer's taste.The source code of instrument drivers is modular, readable and

drives for the most popular types of instruments.tion to the low level drivers, there are high level (instrument)form, of the operating system, often of the instrument. In addiprogramming; the options they offer are independent of the platDrivers are supplied with libraries of functions for the hardware

ments without coniiicts.

can be mixed with register-based (VXI, DAQ boards) instruinstruments. Message—based (GPIB, RS232, VXI) instruments

controlled instruments - VME/VXI modular instruments — RS232types of data acquisition material - plug-in I/O boards - GPIBLabVIEW includes the low level (interface) drivers for four

Instrument Drivers

their way of working.another VI, and sub—VI's can be opened interactively to examineEvery Wrtual Instrument (VI) can serve as a sub-program forlevel).method (and user interface) for any type of function (low or highity. It also has the advantage of using the same programmingLabVIEW is unique for hierarchy, expandability and homogene

and shareable between users and applications.chy). Every module must be testable/developable independently,of modules, connected either horizontally or vertically (hierarComplex programs must be subdivided into an arbitrary number

Modularity


18 OCR Output

ification.

each platform, and the programs (Vls) are portable without modThe user interface and all the library functions are the same on

DEC stations.

and Power PC, IBM PC compatibles, Sun Sparcstations andLabVIEW runs on the most popular platforms, Apple Macintosh

Portability

applications.Mathematica, Matlab or HiQ, supporting the iile formats of theseconnection to databases. Special drivers are available for Igor,LabVIEW has drivers for TCP/IP network connection and for

Communication

graphically, and thus maximize the transmitted information.LabVIEW offers simple routines to display and correlate data

infomation of data.

sometimes obscure, unsuitable to demonstrate the relational


19 OCR Output

Finally, programming with LabVIEW is fun! (anyway, more than

LabVIEW is suitable for all these tasks.

complex processes with many simultaneous inputs outputsbeyond human capability, such as star tracking with a telescope,bration of series produced equipment, high precision operationsof data in a short time, repetitive operations such as test and calispeed operations such as pulse power diagnostics, collecting lotcollection such as environmental monitoring and control, highMany operations require automation: long term, low speed datatakes measurements (and decisions) and presents the results.cesses, in which the computer govems a sequence of events,between simple data acquisition, and automated, hands-off pro

It is also an excellent automation tool. Note the difference

ming language and the parallelism of concurrent programs.guage. It has the computational ability of a classical programwithout having to resort to the use of another programming lanones, like displaying the result of advanced spectral analysis,ing a particular register of an instrument, to the highest levelthe user to perform from the lowest level functions, like accessLabVIEW is a complete tool, and a complete program. It allows

8 - CONCLUSION


20 OCR Output

tool- it's a true programming method, as we have seen.LabVIEW iconic programming is not simply an organisationalreverting to standard programming languages.their turnkey nature, but impossible to expand/modify withoutoffer a pre—set number of operations, simple to use because ofhide just conventional programming methodologies. These iconsAnother imitated feature is iconic programming - but often iconstual language based programming system.top level user interface added to an otherwise conventional, texpanel oriented user interface. Quite often it is simply a display!Following LabVIEW, most instrument softwares offer a front

IMITATORS

250-500MBy for professional use.Similarly, the minimum Hard Disk space is 120 MBy, but

20-32MBy for professional applications.The minimum memory for LabVIEW use is 8 MBy, and

MACHINE REQUIREMENTS

an extemal smart controller (PLCs, embedded processors).For more stringent needs it’s better to use a dedicated machine or

hold down the mouse button, or scroll down a menu).avoid receiving mail on a Sun, or inserting a floppy in a MAC, orFor LabVIEW the real time scale unit is about 0.1 sec (if you

45Hz, and so on, all the way down to nanosecond phenomena.that!). The real time {light control of an FI6 plane are sampled atrequires a response time of about 1 minute (even PCs can doFor example, the real time control of a house heating system

occurrence.

puter system's latency - the time it takes to respond to an externalthe cycle time or sampling rate for data exchange and the comdepends on your system temporal response. This includes both(Picked up from G,]. book). The precise definition of real time

REAL TIME

9 - ANNEX


21 OCR Output

Slide 20a Integrating your Instrumentation

Slide 19b Networking in T&M

Slide 19a Dynamic Data Exchange

Slide 18b File I/O and Hard Copy

Slide 18a Screen I/O

Slide 17b Data Presentation Options

Slide 17a Analysis Summary

Slide 16b Other Analysis Functions

Slide 16a Signal Generation/Simulation

Slide l5b Time Domain Analysis

Slide 15a Time Domain Analysis

Slide l4b Digital Filters

Slide 14a Gabor Spectrogram

Slide 13b Joint Time-Frequency Analysis

Slide 13a Smoothing Windows

Slide 12b Digital Signal Processing (DSP)

Slide 12a Analysis in LabVIEWData Analysis

Slide 1lb Graphical Programming

Slide lla LabVIEW Product History

Slide 10b LabVIEW - A GUI and a Graphical Programming MethodSlide 10a Virtual Instrument Framework Example - LabVIEW

Slide 9b The LabVIEW Lego

Slide 9a The Ideal SystemData Acquisition

Slide 8b Software for Instrumentation

Slide 8a PCMCLA GPIB Interface

Slide 7b Ethernet based Control System

Slide 7a VXI Instrument Drivers

Slide 6b VXI Controllers

Slide 6a — VXI - An Open Architecture with Shared Processor Bus and Timing

Slide 5b VXI "VME Extensions for Instrumentation"

Slide 5a SCXI — Three~Port Signal Conditioning System

Slide 4b Analog Signals

Slide 4a Wide Range of Performance

Slide 3b Multifunction I/O Board

Slide 3a Plug—In Data Acquisition Boards

Slide 2b RS-232 Serial Connection

Slide 2a GPIB Programming Example

Slide lb Instrumentation Today

Slide la Evolution of Instrumentation

Instrumentation

10 · Slides


S|ide1 b) OCR Output

Wevelorm

CurrentVoltage

or UUT PressureProo•}¥ Temperature

Voltage~Contr•|§Imu|us

/ RS232 Instruments.

?` ..»r?°

\ VXI Instruments

//, /\ IEEE488Instruments

s ’>•'

Conditioning ,A._>\Slam. B*f'°• ;2‘>’rSoItwsre

AcquisitionPIug·ln Date

Computer

Instrumentation Today

Slide 1 a)

1970 . 1980 1 990

Q. =• Q:.3:: _ wr

Analog Instrumentation

....wsa

is i!with RTSIIEEE 488 Rack and Stack System M___ ______DAQ Boards

GUI

Fully Programmable System |·? 7 ¤[%¢X¤¢h•••¤•

'i L: i 5

Virtual instrumentation ___.»·*‘

OCR OutputEvolution of Instrumentation

b) OCR Output

Common RS-232 instruments - digital thermometers, scales

Each port can communicate with only one instrument

Port is standard on most computers; cabling is not standard

PARITY BIT START BIT

STOP BIT

|"s"°m°mComputer £t. l.1·A¤g¤_g nm.; cmgtpmn %‘%oé%%=~==»¤11111010oo¤0101111 ?1E2?uii?

asm cable

RS-232

Slide 2 a)

Large installed base of instruments

Control up to 14 instruments

Standard cable

Transfer rate of more than 1 Mbytes/s

8-bit parallel protocol

Remote programming standard since 1975

_ • _ _ DMM at address 6

IOO i -. E!I O Q » .99

• ' ' ‘“'•¤ ' ""¤Intsrfacb @3 I ls Board 0

GPIB Programming Example

b) OCR Output

Self-calibration

Three 16-bit counters

Eight digital I/O linesA.'._M|O_16X

Two 12-bit DACs

Continuous and interval scanning

Pretrigger and posttrigger modes

256·sample deep FIFO

using Nl·PGIA100 kHz sampling rate at all gains

Programmable gains up to 100

16-bit ADC with 16 analog inputs·

Multifunction I/O Board

Slide 3 a)

ono emu‘``` "

ytput/Qutput11ming

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Input/OulpviAnalog

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b)

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Considerations for Plug·ln Boards

ChromatographStrainSingle-shot events SonarFlovyBlood pressure SpeechPressureECG vibrationTemperature

DC Signal Time Domain Signal Frequency Domain Signal

Analog Signals

Slide 4 a)

Performance (Analog Input)

se50 kHz sampling12-bitLow·power pgPC·LPM·16 75 RH;

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Wide Range of Performance

b) OCR Output

Lacks front panels - requires GUI

More than 500 VXI instruments

More than 50 vendors offering- VXI products

computer _architecture

Combines instruments with modern

IEEE standard 11.55

VXI "VME Extensions for lnstrumemation'

Slide 5 a)

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b)

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Slide 6 a)

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b) OCR Output

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Slide 9 a)

Standard interface, top to bottom

Consistent, unified paradigm

Modular, reusable components

Structured design and packaging

inIntuitive operation

The LEGO!

THE IDEAL SYSTEM

b)

Rapidly build, test, and modify

Familiar technique__ ___ ___ w OCR Output

Block Diagram

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Front Panel

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instrumentation systems2-:

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Slide 10 a)

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‘1 b) OCR Output

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Slide 11 a)

LabVIEW Concept

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b) OCR Output

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Slide 12 a)

X : umm.`

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No need to format acquired dataE LlTightly coupled with acquisition Vls

s'h••F? Ihwer

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Slide T3 b')‘OCR Output

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Slide 1 3 a)»

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Slide 14 a)

Solves window selection problems

Better SNR

Faster than STFT

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Slide 15 a)

Process Control

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Slide 16 a)

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Slidé 17ia)

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No need to format acquired data

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Define your own instruments

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b)

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Slide 18 a)

Custom obiects

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9 b) OCR Output

LabVIEW supports TCP/IP

Standard on Sun workstations

Monitor remote PTOCBSSBS

Share test results

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Slide 20 a)

Process

or

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RS-232 Instruments VXI Instrumentsditionlnq

Boards and SlgnslPlugeln Data Acqulsltlon

GPIB Instrum

Networking

LabVIEW

Computer

Integrating Your Instrumentation

Software advances in measurement and instrumentation

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