Ldc Omm Tds Manual

LDC 3744B - OMM 6810B - TDS 210

LabVIEW 5.1SOFTWARE

Microphotonics Research LaboratoryKoç University Physics Department

Rumeli Feneri Yolu, Science Building, Room 147 Sariyer, Istanbul 34450 Turkey Credits: Şenol İşçi

http://microphotonics.ku.edu.tr/KocUniversityMap-Istanbul.jpg

http://microphotonics.ku.edu.tr/KocUniversityMap-Sariyer.jpg

TABLE OF CONTENTS

1. Introduction 3

2. Installation 3

2.1. Checking System Requirement 3

2.1.1. Requirements for the Hardware 3

2.1.2. Requirements for the Software 4

2.2. Installing the LDC&OMM&TDS System 4

2.3. Installing the Software 4

3. Getting Started 5

3.1. Using the Mouse and Drop-down Menu 5

3.1.1. The Mouse 5

3.1.2. The Drop-down Menu

6

3.2. Menus, Tool Bar, Controls and Indicators

6

3.2.1. Menus

6

3.2.1.1. File Menu 6

3.2.1.2. Edit Menu 7

3.2.1.3. Operate Menu

7

3.2.1.4. Windows Menu 7

3.2.1.5. Help Menu 7

3.2.2. Toolbar 7

3.2.2.1. Description 7

3.2.2.2. Running VI 8

4. LDC_OMM_TDS_MAIN.vi 8

4.1. User Interface

9

APPENDIX 1 GPIB 14

Microphotonics Research Laboratory Page 2 07-Apr-23

APPENDIX 2 VISA 15

CONTACT INFORMATION 16

1. Introduction

The LDC&OMM&TDS software provides an interface between a laser

diode controller, an optical multimeter and a digital oscilloscope. The

LDC&OMM&TDS system consists of an ILX Lightwave LDC 3744B Laser Diode

Controller, an ILX Lightwave OMM 6810B Optical Multimeter, and a Tektronix

TDS 210 Digital Oscilloscope.

The software was written mainly in LabVIEW version 5.1 for Windows.

Most of the sub VIs’ utilized were from the device manufacturers’ software

resources. For fastest image display and image quality, it is recommended

that you have a minimum of 32MB of RAM and a monitor resolution of

1024x768 pixels.

2. Installation

Refer to the ILX LDC, ILX OMM and TektronixTDS user manuals for

proper power and communications, as well as any other pertinent installation

information. All devices have GPIB interfaces, which are IEEE 488.2-

compatible (see Appendix 1 for further information).

2.1. Checking System Requirement

Check to make sure that your computer meets the minimum

requirements for the LDC&OMM&TDS system.

2.1.1. Requirements for the Hardware

A Personal Computer


PCI-GPIB Board

High-quality shielded GPIB cabling to meet your system needs

A mouse or any other pointing device.

A VGA, SVGA display, or 1024x768.

Minimum of 32 MB of RAM recommended.

2.1.2. Requirements for the Software

Any IBM compatible machine with an 80386 processor or higher.

A hard disk with at least 10MB free space, and 7MB is needed for

installation.

Microsoft Windows 95 or newer in standard or enhanced mode.

2.2. Installing the LDC&OMM&TDS System

Before making any connections between a computer to the LDC, OMM,

and TDS, all of the devices should be off.

Connect all devices to the PC with GPIB cables.

The GPIB address (software default) for LDC is 1.

The GPIB address (software default) for TDS is 2.

The GPIB address (software default) for OMM is 3.


Connect all devices’ power cables.

For detailed description of hardware installations and cable connections,

please refer to the manufacturers’ user manuals.

2.3. Installing the Software

1. Open “LDC_OMM_TDS.LLB”, which is a Labview library file.

2. Select the LDC_OMM_TDS_MAIN.VI, which is the application software

for the LDC 3744B OMM 6810B TDS 210 system.

3. Getting Started

Once the “LDC_OMM_TDS_MAIN.VI” has been opened, you are ready to

get started.


Library Files

3.1. Using the Mouse and Drop-down Menu

3.1.1. The Mouse

The mechanics of using a mouse with the software conforms to the

Microsoft Windows standard. The following conventions are used in the

manual when explaining manipulations with the mouse: “Clicking” the mouse

on an object consists of moving the mouse cursor until it is pointing to the

object and depressing the specified mouse button once or twice in quick

succession. If you have reconfigured your mouse for other-handed use,

switch the references (specified or assumed) to the right and left buttons.

3.1.2. The Drop-down Menu

Menu options are referenced as “to level menu”: “submenu option”

like these following examples:

File

Open… is referenced as File:Open…

Help

Show Help is referenced as Help: Show Help

3.2. Menus, Tool Bar, Controls and Indicators

This section has detailed descriptions about the menus, tool bar,

controls and indicators. For each menu, a brief description of each command

is given. In addition, LabVIEW programs are called virtual instruments (VIs).

3.2.1. Menus

3.2.1.1. File Menu

Open. Opens an existing VI. A status dialog is displayed while that VI is

opening. This status dialog identifies the VIs that are currently being

loaded and gives you an opportunity to cancel the load process.

Close. Closes the active window and does not save any changes you have

made.


Printer Setup… Sets configuration options for the printer. You can

change the orientation of printout (landscape versus portrait). Printer

Setup settings are saved with your VI.

Print Window… Prints out the contents of the currently active window.

Using this option, you can make a quick printout with the minimum

number of prompts.

Exit. Quit LabVIEW.

3.2.1.2. Edit Menu

Preferences… Sets preferences for memory, disk, and display.

3.2.1.3. Operate Menu

Run. Executes the current VI.

Print at Completion. Prints the contents of a VI’s front panel after each

execution.

Log at Completion. Logs a time stamp and the data in all front panel

controls of a VI to a separate datalog file.

Data Logging. Displays data logging options. (Optional if you have

LabVIEW software).

Reinitialize All to Default. Sets all controls and indicators to their

default values.

3.2.1.4. Windows Menu

Show VI Info... Displays the VI file path, revision number, and memory

usage.

Show Clipboard. Displays the contents of the clipboard.

Full Size. Uses the entire screen to display the active window.

3.2.1.5. Help Menu

Show Help. Is a Context-sensitive Help window that displays a function’s

or VI’s parameters, parameter type definitions, and the description for

the object.

About. Information on LabVIEW software version number and serial

number.


3.2.2. Toolbar

3.2.2.1. Description

The LabVIEW toolbar contains four command buttons as in figure 1.

Fig. 1. LabVIEW Toolbar

Run button. Runs the VI.

Continuous run button. Runs the VI over and over.

Stop button. Aborts VI execution.

Pause/Continue button. Pauses VI execution/Continue VI execution.

3.2.2.2. Running VI

You can run a VI by selecting Operate: Run or clicking on the run

button.

While the VI is executing, the run button changes appearance. If the VI

is running at its top level, the run button looks like the illustration

shown to the left.

If the VI is executing as a sub VI, the run button changes to look like

the illustration shown to the left.

4. LDC_OMM_TDS_MAIN.vi

The application gets spectral data by tuning the temperature via LDC at

constant current mode.

The system designed upon VISA (see Appendix 2 for further information) is a

standard I/O Application Programming Interface (API) for instrumentation


programming. Our GPIB system uses a single GPIB interface to communicate

with several GPIB instruments. Each instrument is configured to use a

different primary address. The GPIB controller (Our Personal Computer)

acquires and displays a fixed number of readings from each instrument. The

Programming is based on Single-Threaded Solution. In the single-threaded

solution, our application does the following:

1) Set the control parameters for LDC TEC and LAS operations.

2) Set the TDS reading to “Mean” measurement and acqusition channel

(software default for measurement channel is Channel1)

3) Initialize the OMM.

4) Go to starting Temperature value

5) Scan temperature up till the stop temperature point is reached.

6) While more readings to acquire

a. Tell LDC to send data

b. Acquire data from LDC

c. Tell TDS to send data

d. Acquire data from TDS

e. Tell OMM to send data

f. Acquire data from OMM

g. Display acquired data

7) Save data to the specified folder

4.1. User Interface

The interface is mainly composed of LDC parameter controls and status

displays for various settings of LDC, OMM and TDS. The graphs display the

acquired data.


Status Display and Stop Button

During the operation, you will see the actions of the Application Software and

be notified in case of error.

Stop Button stops the Scan Procedure and allow saving data before

completely finishing execution.


LDC Settings

Set Point (mA) : LDC can operate at

constant power or constant current

mode. In our application, Constant

mode is selected as the software

default. Set Point (mA) will set the LDC

to Constant Current Low bandwidth

mode.

tempset_start is the starting scan

temperature value

tempset_stop is the stopping scan

temperature value

Temperature Limit set the maximum

temperature The LDC will allow before

generating an action. During controller

operation, is this limit is reached, The

Laser and TEC output will be shut off to

protect the laser.

TEC Current Limit Function limits the controller’s output current so that

the instrument does not provide more current than your TE module can

safely handle.

Temperature Conversion Constants:

These sensor calibration constants are necessary for accurate conversion to

actual temperature. Please refer to whitepaper of your thermistor used in

LDC for necesaary information.

GAIN is the TE control loop gain. The GAIN function sets the analog feedback

gain, which in part, determines how fast the actual temperature reaches and

settles to the setpoint temperature.

In LDC&OMM&TDS software, during the scan, the TE current

limit is continuously increased at number of data point taken

determined by TElim Update at TE lim step rates. This


method allows increase in the number of readings from the system. For

different laser diodes, User can run the application for several update

parameter schemes in order to get the best setting.

Update Parameters toggle switch updates

the LDC control parameters above

Las Output LED button will be on when the current source output

of the laser diode is enabled.

TEC Output LED butoon will be illuminated when the TE control

loop is enabled.

This Function allows immediate temperature

setpoint update.

These displays are the data acquired

from the system after scanning.

folder specifies the path, in which the readings will be saved.


Oscilloscope is data coming from TDS. Unit,

Source and Type are the parameters set for TDS.

Temperature(C) is the current temperature limit

display. TEC Current (A) display is updated during

the scan. GAIN and the C1,C2,C3 indicators show

the current values set.

Power and wavelength measurements are

acquired from OMM.

Temperature Graph displays the temperature values during scanning. X-axis

is the number of data taken. This graph is hany when the user arranges the

scan settings such as TE lim start, TE lim Update mentioned above.


Scope graph displays the data acquired from the TDS

This graph displays the TDS reading as a function of Temperature. It will

show up at the end of scan process.

APPENDIX 1

GPIB (General Purpose Interface Bus)

Often referred to as the IEEE-488.2 bus, GPIB bus or HP-IB bus, the GPIB

(General Purpose Interface Bus) is a standard for instrumentation

communication and control for instruments from manufactures the world

over. In 1965, Hewlett-Packard designed the Hewlett-Packard Interface Bus

(HP-IB) to connect their line of programmable instruments to their

computers. Because of its high transfer rates (nominally 1 Mbytes/s), this

interface bus quickly gained popularity. It was later accepted as IEEE

Standard 488-1975, and has evolved to ANSI/IEEE Standard 488.1-1987.

Today, the name General Purpose Interface Bus (GPIB) is more widely used

than HP-IB. ANSI/IEEE 488.2-1987 strengthened the original standard by

defining precisely how controllers and instruments communicate. Standard

Commands for Programmable Instruments (SCPI) took the command

structures defined in IEEE 488.2 and created a single, comprehensive

programming command set that is used with any SCPI instrument.

The GPIB provides handshaking and interface communications over an 8 bit

data bus employing 5 control and 3 handshake signals.


Equipped with a PCI-GPIB, a personal computer can:

Control GPIB instruments.

Gather data from GPIB test equipment.

Become a data acquisition station in a GPIB system.

APPENDIX 2

VISA

VISA is a standard I/O Application Programming Interface (API) for

instrumentation programming. VISA by itself does not provide

instrumentation programming capability. VISA is a high-level API that calls

into lower level drivers. The hierarchy of NI-VISA is shown in the figure below.

VISA can control VXI, GPIB, or serial instruments, making the appropriate

driver calls depending on the type of instrument being used. When

debugging VISA problems it is important to keep in mind that this hierarchy

exists.


GPIB interfacing

VISA Is the Standard

VISA is the standard API for instrument drivers throughout the

instrumentation industry. In addition, you can use one API to control a suite

of instruments of different types, including VXI, GPIB and serial.

Interface Independence

VISA uses the same operations to communicate with instruments regardless

of the interface type. For example, the VISA command to write an ASCII

string to a message-based instrument is the same whether the instrument is

serial, GPIB, or VXI. Thus VISA provides interface independence. This makes

it easier to switch bus interfaces, which means that users who must program

instruments for different interfaces only need to learn one API.

Platform Independence

VISA is designed so that programs written using VISA function calls are easily

portable from one platform to another. To ensure platform independence,

VISA strictly defines its own data types. Therefore issues like the size, in

bytes, of an integer variable from one platform to another should not affect a

VISA program. The VISA function calls and their associated parameters are

uniform across all platforms. Software can be ported to other platforms and

then recompiled. A LabVIEW program can be ported to any platform

supporting LabVIEW.

Easily Adapted to the Future

Another advantage of VISA is that it is an object-oriented API that will easily

adapt to new instrumentation interfaces as they are developed in the future,

making application migration to the new interfaces easy.


For Further Information, Please Contact:

Şenol İşçi :

E-mail: [email protected]

Microphotonics Research Laboratory

Koç University Physics Department

Rumeli Feneri Yolu, Science Building, Room 147 Sariyer, Istanbul 34450

Turkey


mailto:[email protected]

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Ldc Omm Tds Manual

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