Design and Implementation of a LabVIEW based Computer

Design and Implementation of a LabVIEW basedComputer Control for EPR Instrumentation

Diploma Thesis Defense

Matthias Kolja Miehl

October 22, 2010 at 2:30 pm

Milwaukee, Wisconsin, USAMedical College of WisconsinMACC Fund Research Center

Room L3075

LabVIEW based Computer Control

I Control and acquisition frameworkI Easily change hardwareI All experiments in one application

Figure: L-Band spectrometer at MCW’s Biophysics Research Department

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I Control and acquisition frameworkI Easily change hardwareI All experiments in one application

Figure: L-Band spectrometer at MCW’s Biophysics Research Department

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Contents

1 Introduction

2 Concept

3 Implementation

4 Test

5 Summary and Vision

Contents

1 Introduction

2 Concept

3 Implementation

4 Test



Introduction

Motivation

NeedMCW Research:

I New experiments

I Different spectrometers

I Changing Hardware

SituationUse of separate programs for

I each experiment,

I each spectrometer, and

I were rewritten for new instruments.

ProblemI Labor and time intensive tasks

I Reduction of actual research time

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Introduction

Motivation

NeedMCW Research:

I New experiments


I Changing Hardware


I each experiment,




I Reduction of actual research time

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Introduction

Motivation

NeedMCW Research:

I New experiments


I Changing Hardware


I each experiment,




I Reduction of actual research time8 / 72


Introduction

Motivation

MotivationIncrease the actual research time by reducing redundancy.

I Experiment implementation

I Changing hardware

GoalVersatile framework:

I All experiments

I Every spectrometer

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Introduction

Motivation

MotivationIncrease the actual research time by reducing redundancy.

I Experiment implementation

I Changing hardware

GoalVersatile framework:

I All experiments

I Every spectrometer

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Introduction

Related Work

Existing ApproachesI WinEPR

I EWWin

I SpecMan4EPR

MCW’s RequirementsI Exchange of instruments

I Storing experiment settings

I Easy extension by customer

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Introduction

Related Work

Existing ApproachesI WinEPR

I EWWin

I SpecMan4EPR

MCW’s RequirementsI Exchange of instruments

I Storing experiment settings

I Easy extension by customer

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Contents

1 Introduction

2 Concept

3 Implementation

4 Test



Concept

Key Requirements

Key RequirementsI All experiments in one application

I Instruments easily exchangeable

I Maintainability and extendability

I 32 and 64-bit driver support

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Concept

Overall Structure

Core ofMain Appl.

InstrumentDriver

Instrument

...

...

64-bit

64 or 32-bit

Exp.GUI

...

Controls andIndicators

Logic

InternalData Flow

Inter-ProcessCommunication

Bus

HardwareAbstraction

Hardware

Figure: Overall application structure (concept)

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Contents

1 Introduction

2 Concept

3 Implementation

4 Test



Implementation

Overall Structure and Used Technologies

Core ofMain Appl.

InstrumentDriver

Instrument

ClientTab Controls

Multiple-Loop Appl. Framework

EventStructure

STM

Server asEXE Module

Hardware

...

...

64-bitEXE

64 or 32-bitEXE

Exp.GUI

...


Logic

InternalData Flow


Bus

HardwareAbstraction

Hardware

ImplementationConcept

GPIB, LXI, ...

Figure: Overall application structure (implementation)

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Implementation


Core ofMain Appl.

InstrumentDriver

Instrument

ClientTab Controls


EventStructure

STM

Server asEXE Module

Hardware

...

...

64-bitEXE

64 or 32-bitEXE

Exp.GUI

...


Logic

InternalData Flow


Bus

HardwareAbstraction

Hardware


GPIB, LXI, ...


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Implementation


Figure: Tab control structure of the application19 / 72


Implementation


Figure: Tab control structure as the operator sees it20 / 72


Implementation


Core ofMain Appl.

InstrumentDriver

Instrument

ClientTab Controls


EventStructure

STM

Server asEXE Module

Hardware

...

...

64-bitEXE

64 or 32-bitEXE

Exp.GUI

...


Logic

InternalData Flow


Bus

HardwareAbstraction

Hardware


GPIB, LXI, ...


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Implementation


Figure: Main program event handler loop

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Implementation


Core ofMain Appl.

InstrumentDriver

Instrument

ClientTab Controls


EventStructure

STM

Server asEXE Module

Hardware

...

...

64-bitEXE

64 or 32-bitEXE

Exp.GUI

...


Logic

InternalData Flow


Bus

HardwareAbstraction

Hardware


GPIB, LXI, ...


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Implementation


Figure: Implementation of the main program’s parallel loop structure24 / 72


Implementation


Core ofMain Appl.

InstrumentDriver

Instrument

ClientTab Controls


EventStructure

STM

Server asEXE Module

Hardware

...

...

64-bitEXE

64 or 32-bitEXE

Exp.GUI

...


Logic

InternalData Flow


Bus

HardwareAbstraction

Hardware


GPIB, LXI, ...


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Implementation


Core ofMain Appl.

InstrumentDriver

Instrument

ClientTab Controls


EventStructure

STM

Server asEXE Module

Hardware

...

...

64-bitEXE

64 or 32-bitEXE

Exp.GUI

...


Logic

InternalData Flow


Bus

HardwareAbstraction

Hardware


GPIB, LXI, ...


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Implementation


Core ofMain Appl.

InstrumentDriver

Instrument

ClientTab Controls


EventStructure

STM

Server asEXE Module

Hardware

...

...

64-bitEXE

64 or 32-bitEXE

Exp.GUI

...


Logic

InternalData Flow


Bus

HardwareAbstraction

Hardware


GPIB, LXI, ...


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Implementation

Driver Management

Startup of Drivers

Communication

Main Appl.

Driver 1

Driver 2

Driver 2

starts

text_based_variable.ini

Write port foreach driver

Read portfrom respectivesection

Main Appl.

Driver 1

Driver 2

Driver 2

STM

Port x

Port y

Port z

x, y, z

z

y

x

Figure:28 / 72


Implementation

STM

Advantages:

I Command-based

I Hides transport layer details

I Minimizes network traffic

I Small overhead

I High throughput

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Implementation

STM

Advantages:

I Command-based



I Small overhead

I High throughput

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Implementation

STM

Advantages:

I Command-based



I Small overhead

I High throughput

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Implementation

STM

Advantages:

I Command-based



I Small overhead

I High throughput

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Implementation

STM

Advantages:

I Command-based



I Small overhead

I High throughput

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Implementation

STM

Variant Data

Figure: Code of modified STM write function block

Figure: Code of modified STM read function block

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Implementation

STM

Variant Data


Figure: Code of modified STM read function block

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Implementation

STM

Variant Data


Figure: Code of modified STM read function block36 / 72


Implementation

STM

Variant Data

Figure: Modified STM function blocks for writing and reading

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Implementation

STM

Command-Based Communication Framework

Client/Main Appl. Server/Driver

DataReceiver

Command/Parameter

Sender

Network Communication

Commands + Parameters

Data + Status Information

CommandParser

MediumPriorityTasks

High

Priority

Task

Figure: STM’s command-based communication framework

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Implementation

Main Program and Driver Structure

STM

Main Program

Medium Priority(Transmitter)

Command Parser

Medium Priority(Processor)

High Priority

Event Handler

Transmitter

Receiver

Main

Driver

STM

STM

Dat

aQ

ueu

e

Me

diu

m P

riori

t yQ

ueu

e

Hig

h P

riorit

yQ

ueu

e

STM

STM

Ma

in Q

ueu

e

Figure: Parallel loop structure of main program and drivers

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Implementation

Main Program and Driver Structure

Figure: Actual loop structure of driver

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Implementation

Resulting Information Flow

STM CommandGUI in

Main Appl.Driver Instrument

Instrument Bus

● Event structure● Queue● Main loop● Transmitter loop

● Command Parser● Queue● Medium Priority (Processor) loop● LabVIEW driver function block

STM

Bus CommandSTM Parameter

Figure: Resulting information flow on instrument control change

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Implementation

Usages

Goal: Relation between drivers and instruments

Figure: Instrument control clusters on instrument panel

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Implementation

Usages

Goal: Relation between drivers and instruments

Figure: Instrument control clusters on instrument panel

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Implementation

Usages

usage instrument 1

selects uses

driver 1

instrument 2 driver 2


or

or

Figure: Usage concept

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Implementation

Usages

L-Band.CW sim.ini

; assignment of instrument to usage; ---------------------------------; usage = instrument name[config]stepper motor = "DS345(1)"signal = "DS345(2)"adc = "NI PCI-6024E"

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Implementation

Usages

L-Band.CW sim.ini

; EXE names; ---------; instrument name = driver name[driver]DS345(1) = "srds345"DS345(2) = "srds345"N8241A = "n8241a"N8241A Option 330 = "n8241a"NI PCI-6024E = "ni pci-6024e"

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Implementation

Usages

L-Band.CW sim.ini

; instrument resource names; -------------------------; instrument name = resource name[resource]DS345(1) = "17"DS345(2) = "18"N8241A = "TCPIP0::169.254.1.20::inst0::instr"N8241A Option 330 = "TCPIP0::169.254.1.22::inst0::instr"NI PCI-6024E = "Dev1"

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Implementation

Usages

L-Band.CW sim.ini

; default parameters; ------------------; parameter_DataType = value

[signal]frequency_Digital = 1.000000amplitude_Digital = 3.000000phase_Digital = 0.000000offset_Digital = 0.000000amplitude unit_Ring = 1.000000waveform_Ring = 1.000000write wfm file_Path = "/C/temp/waveform.txt"

[...]

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Implementation

Usages

usage instrument 1

selects uses

driver 1



or

or

Figure: Usage concept

signal DS345

selects uses

sdrs345

N8241A n8241a

N8241A, 330 n8241a

or

or

Figure: Usage implementation

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Implementation

Hardware Abstraction

Goal: Select different instruments for a usage

Main Appl. Driver Instrument

standardizedSTM commands

instrumentspecific

bus commands

Figure: Driver as hardware abstraction layer

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Implementation


Figure: Driver’s command parser loop

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Implementation


Figure: Driver’s high priority loop

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Implementation

Implemented Experiment

Figure: CW experiment GUI Collection page53 / 72


Implementation


Figure: CW experiment GUI Parameters page54 / 72


Implementation


Figure: CW experiment GUI Patrick page55 / 72


Implementation


Figure: CW experiment GUI Varian page56 / 72


Implementation


Figure: CW experiment GUI Instrument panel57 / 72

Contents

1 Introduction

2 Concept

3 Implementation

4 Test



Test

Measurement Setup

Measurement Setup

Sample : Spin labelMicrowave frequency : 1.908 GHz (L-Band)Microwave input power : 120 µWCenter field : 675 GSweep : 105 G, i.e. 622.5 G .. 727.5 GNumber of averages : 5Acquisition time : ≈ 5:30 min

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Test

Results

Figure: Collection page after 2nd collection

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Test

Results

Figure: Collection page after 3rd collection

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Test

Results

Figure: Collection page after 4th collection

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Test

Results

Figure: Collection page after 5th collection

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Test

Results

Figure: Plot of full data.xls

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Contents

1 Introduction

2 Concept

3 Implementation

4 Test



Summary and Vision

Key FeaturesI Can run on all spectrometers

I Can implement all experiments

I Faster experiment implementation

I Improved modularity and flexibility

I 32 and 64-bit driver capability

I Multi-core processors and multi-threading capable

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Summary and Vision

Key FeaturesI Can run on all spectrometers

I Can implement all experiments

I Faster experiment implementation

I Improved modularity and flexibility

I 32 and 64-bit driver capability

I Multi-core processors and multi-threading capable

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Summary and Vision

IssuesI Improve thread allocation

I Decrease time it takes to display acquired data

I Emphasize the common basis of experiments

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Summary and Vision

DiscoveriesI Shared variables work unreliable for some applications

I Module based concept for large projects

I STM with case structure to avoid polling for new messages

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Summary and Vision

Future ImprovementsI Adaptive Signal Averaging Technique

I Technical Data Management Streaming (TDMS)

I Implement more drivers

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Any Questions?

Many thanks for your attention!

Documents

Design and Implementation of a LabVIEW based Computer