CONTENTS

1. INTRODUCTION: 6

2. OBJECTIVE 7

3. ABSTRACT

3. DESCRIPTION OF THE LASER SYSTEM 7

3. 1 PRINCIPAL COMPONENTS OF LASER SYSTEM 7

3. 2 TYPES OF LASER 8

3.2.1 GASDYNAMIC LASER 8

4. SOFTWARE AND HARDWARE COMPONENTS 9

4.1 LASER DIODE 9

4.2 POSITION SENSING DEVICE 10

4.3 STEPPER MOTOR 11

4.4 DIGITAL ENCODER 15

4.5 SOLID STATE RELAY 18

4.6 PCI 1710 DATA ACQUISITION CARD 18

4.7 DMC MOTION CONTROLLER 20

4.8 GALIL TOOLS 20

4.9 LABVIEW 21

5. EXPERIMENTAL SETUP 22

6. RESULTS AND DISCUSSION 23

7. REFERENCES 24

ACKNOWLEDGEMENT

It gives me immense pleasure in presenting my training report. I would like to take

this opportunity to express my deepest gratitude to the people, who has contributed

their valuable time for helping me to successfully complete this training.

I would take this opportunity to express my gratitude to Mr. R. K. Jain Scientist "G"

for providing me opportunity to work in ODG division. I am thankful to Mr. A.K.

Srivastava Scientist “F” LASTEC, DRDO, Delhi for his guidance, helpful

discussions, support and encouragement throughout this project study. I also

express my thanks to my supervisor in the LASTEC, DRDO Delhi Dr. K. C. Sati

Scientist "E" for his invaluable suggestions and innovative ideas to complete this

work. Their hard working nature and passion towards research have always been

source of inspiration for me.

I would like to thank Defence Research and Development Organization, Delhi for

conducting such kind of training, my college staff and all the people who were

directly and indirectly involved in the activity.

I am thankful to every member of the ODG LASTEC for making this summer training

period an inspirational experience.

1 .INTRODUCTION

D.R.D.O (Defence Research and Development Organization)

Defence Research & Development Organisation (DRDO) works under Department of

Defence Research and Development of Ministry of Defence. DRDO dedicatedly

working towards enhancing self-reliance in Defence Systems and undertakes design

& development leading to production of world class weapon systems and equipment

in accordance with the expressed needs and the qualitative requirements laid down

by the three services. DRDO is working in various areas of military technology which

include aeronautics, armaments, combat vehicles, electronics, instrumentation

engineering systems, missiles, materials, naval systems.

L A S T E C (Laser Science and Technology Centre)

Fig 1.1 LASTEC Labs

The Laser Science and Technology Centre had its beginning in 1950 as the Defence

Science Laboratory (DSL)) established as a nucleus laboratory of DRDO (then

known as Defence Science Organisation). In the beginning, DSL operated from the

National Physical Laboratory building.Later, on April 9th 1960, it was shifted to

Metcalfe House and Menon inaugurated by then Raksha Mantri Dr Krishna in the

presence of Pt. Jawahar Lal Nehru. DSL had seeded for as many as 15 present

DRDO labs with core groups working in much diverse area. In 1982, the Laboratory

moved to a new technical building in Metcalfe House complex and was rechristened

as Defence Science Centre. The centre consolidated its R&D activities towards more

specific and application oriented areas, such as liquid fuel technology, spectroscopy,

crystallography, system engineering, biotechnology etc. DSC also was given a new

charter of duties with its major thrust on LASERS. In 1986, the centre was made

responsible for the development of high power lasers for Defence applications as

one of its major missions. The lab has got its present identity as “Laser Science &

Technology Centre” on 1 Aug 1999 since it is working in laser and related areas.

OBJECTIVE

A complete laser system employs many assemblies like gain medium, pumping

cavity, cooling mechanism, resonator and power extracting windows. In high power

laser resonator the operation of many systems requires remote control of various

units.

In the present system, the entire laser operation employs diode alignment laser, PSD

for monitoring of alignment of output power and powering of various electronic units.

Laser diode and PSD units are employed to perform these operations. Both of these

assemblies require shutter in front of these devices, the operation of shutter is

required to be controlled remotely during actual laser operation. Moreover powering

of these devices that is laser diode and PSD system is also required to be controlled

from a fixed distance. Hence an application program is developed for all these

operations using Lab View and Gall software.

2. Abstract

The realignment of a mirror in resonator requires a closed loop feedback control

system. The system utilise PSD, Laser Diode, stepper motor, digital encoder, data

acquisition card and motor controller card, motor driver for controlling the sequence

of operation. In aligned position of mirror, beam from diode laser fall on to centre of

the mirror which reflects the beam back to the centre of the PSD. The central

position of spot is taken as reference position. When the mirror is misaligned, the

position of light beam on PSD shifts from its reference position. The output signal

from PSD is then compared with the reference position. These data are processed in

data acquisition card in to find the misalignment of mirror. The necessary command

is then generated through controller to move mirror in correct direction through

stepper motor for realignment of mirror. The no of step counted with the help of

digital encoder. The graphic user interface for control of operation is shown below:

Conclusion: The realignment of mirror with accuracy 10 arc sec. achieved

within time frame of 5 sec.

3 . DESCRIPTION OF LASER

A laser is a device that emits light (electromagnetic radiation) through a process

called stimulated emission. The term laser is an acronym for light amplification

by stimulated emission of radiation.Laser light is usually spatially coherent, which

means that the light either is emitted in a narrow, low divergence beam, or can be

converted into one with the help of optical components such as mirror or lenses.

Typically, lasers are thought of as emitting light with a narrow wavelength spectrum

("monochromatic" light). This is not true of all lasers, however: some emit light with a

broad spectrum, while others emit light at multiple distinct wavelengths

simultaneously. The coherence of typical laser emission is distinctive. Most other

light sources emit incoherent light, which has a phase that varies randomly with time

and position.

3.1 PRINCIPAL COMPONENTS OF LASER SYSTEM

1. Gain medium

2. Laser pump source

3. Resonator

Fig 3.1 Schematic diagram of a basic laser

The process of supplying the energy required for the amplification is called pumping.

The minimum pump power needed to begin laser action is called the lasing

threshold. The energy is typically supplied as an electrical current or as light at a

different wavelength. Such light may be provided by a flash lamp or perhaps another

laser. Most practical lasers contain additional elements that affect properties such as

the wavelength of the emitted light and the shape of the beam. Although with a

population inversion we have the ability to amplify a signal via stimulated emission,

the overall single-pass gain is quite small, and most of the excited atoms in the

population emit spontaneously and do not contribute to the overall output. To turn

this system into a laser, we need a positive feedback mechanism that will cause the

majority of the atoms in the population to con- tribute to the coherent output. This is

the resonator, a system of mirrors that reflects undesirable (off-axis) photons out of

the sys- tem and reflects the desirable (on-axis) photons back into the excited

population where they can continue to be amplified Now consider the laser system

shown in figure 36.5. The lasing medium is pumped continuously to create a

population inversion at the lasing wavelength. As the excited atoms start to decay,

they emit photons spontaneously in all directions. Some of the photons travel along

the axis of the lasing medium, but most of the pho- tons are directed out the sides.

The photons traveling along the axis have an opportunity to stimulate atoms they

encounter to emit photons, but the ones radiating out the sides do not. Furthermore,

the photons traveling parallel to the axis will be reflected back into the lasing medium

and given the opportunity to stimulate more excited atoms. As the on-axis photons

are reflected back and forth interacting with more and more atoms, spontaneous

emission decreases, stimulated emission along the axis predominates, and we have

a laser. Finally, to get the light out of the system, one of the mirrors is has a partially

transmitting coating that couples out a small per- centage of the circulating photons.

The amount of coupling depends on the characteristics of the laser system and

varies from a fraction of a percent for helium neon lasers to 50 percent or more for

high-power lasers.

3.2 POPULATION INVERSION MECHANISM

Population inversion, which gives rise to laser action, is brought about in different

media by various mechanisms. In gases, metal vapors, and plasmas, the inversion is

brought out by applying a voltage drop across the elongated gain medium thereby

producing an electric field that accelerates the electrons. These rapidly moving

electrons then collide with gas atoms and excite them to a number of excited energy

levels. Some of these levels decay faster than the others, leaving population

inversions with some higher levels. If the population in the excited levels is high

enough, then the gain may be sufficient to make a laser. Most gas lasers have

relatively low gains and therefore require the use of amplifier lengths of the order of

25 to 100 cm.

Fig 3.2 Amplification by stimulated emission

Typical pressures for gas lasers range from 0.0001 to 0.001 atm, although there

are some gas lasers that operate at normal atmospheric pressure and above. In

liquids, most of the excited states decay so rapidly due to collisions with surrounding

atoms or molecules that it 1s difficult to accumulate enough population in an upper

laser level and to achieve significant gain. Fluorescent dyes are the best liquid

media for lasers; their excited energy levels are populated either by flash lamps or by

lasers.

In solid state lasers, population inversions are brought out by implanting impurities

(which give the laser action) within a. host material, such as a crystal or a glass and

then exciting them with a suitable light. The impurity concentration is usually in the

range of 0.01-3.0 per cent. In most of the solid state lasers, the impurities are in the

form of ions in which the energy states are shielded from the surrounding atoms so

that the energy levels

are narrow. A flash lamp is used to excite the ions to a large number of upper energy

levels. The excited ions decay quickly to the met stable upper level where they stay

for considerable time (of the order of milliseconds) before terminating of the lower

energy level, leading to the stimulatede mission no flase rradiation. Inversions in

semiconductors are produced when a p-n junction is created by joining two slightly

different semi conducting materials, viz., n- and p-type materials (similar to a

transistor). Then-type materials have an excess of electrons whereas the p-type

materials have an excess of holes (missing electrons). When they are joined, excess

electrons of the n-type materials are pulled over into the p-region causing the

electrons and holes in those regions to recombine and emit radiation. If an external

electric field is applied in an appropriate direction, by applying a voltage across the

junction, more electrons and holes can be pulled together causing them to

recombine and emit more radiation producing inversion

3.3 LASER PROPERTIES

The use of a laser for various applications depends upon the beam properties of

laser such as direction, divergence, and wavelength or frequency

characteristics, which can be adjusted by the laser components. The features

affecting the beam properties of laser include: size of the gain medium, location,

separation and reflectivity of the mirrors of the optical cavity, and presence of losses

in the beam path within the cavity. Some of these features determine the unique

properties of the laser beam, referred to as laser modes. The laser modes are

wavelike properties relating to the oscillating character of the beam as the beam

passes back and forth through the amplifier and grows at the expense of existing

losses. The development of laser modes involves an attempt by competing light

beams of similar wavelengths to fit an exact number of their waves into the optical

cavity. For example, a laser mode of green light having a wavelength of exactly 5 x

10-5 cm will fit exactly 1,000,000 full cycles of oscillations between laser cavity

mirrors separated by a distance of exactly 50 cm. Most lasers have several modes

operating simultaneously in the form of both longitudinal and transverse modes

which give rise to a complex frequency and spatial structure within the beam which

otherwise appears as simple pencil-like beam of light.

3.4 TYPES OF LASER

Solid-State Laser

Gas Laser

Liquid laser (Dye Laser)

Semiconductor laser

The scope of this project involves operation of Gasdynamic laser which is briefly

described below.

3.4.1 GASDYNAMIC LASER

Fig.3.1 Gas Laser

Gas dynamic laser falls in the category of gas laser. Gas Dynamic Laser (GDL) is laser based on differences in relaxation velocities of molecular vibrational states. The laser medium gas has such properties that an energetically lower vibrational state relaxes faster than a higher vibrational state, thus a population inversion is achieved in a particular time. Helium cadmium (HeCd) lasers are, in many respects, similar to

the HeNe laser with the exception that cadmium metal, the lasing medium, is solid at room temperature. Because of its excellent wavelength match to photopolymer and film sensitivity ranges. As mentioned above, cadmium, a metal, is solid at room temperature. For lasing to occur, the metal must be evaporated from a reservoir and then the vapor must be distributed uniformly down the laser bore. This is accomplished through a process called electrophoresis. Because cadmium will plate out on a cool surface, extreme care must be taken in the design of the laser to contain the cadmium and to protect the optics and windows from contamination, since even a slight film will intro duce sufficient losses to stop lasing. The end of life usually occurs when cadmium is depleted from its reservoir.

Pure Gas dynamic lasers usually use a combustion chamber, supersonic expansion nozzle resonator and CO2 as a active laser medium in mixture with nitrogen or helium. Gas dynamic laser could be however pumped not only by combustion, but by any adiabatic expansion of gas. Any hot and compressed gas with appropriate vibrational structure could be utilized.

4. SOFTWARES AND HARDWARE COMPONENTS USED

1. Laser diode

2. Position sensing detector

3. Stepper motor

4. Digital Encoder

5. Solid state relay

6. PCI 1710

7. Galil DMC 18X2 Motion Controller

8. Galil Tools

9. LabVIEW (version 7.1)

4.1 LASER DIODE

A laser diode, like many other semiconductor devices, is formed by doping a very

thin layer on the surface of a crystal wafer. The crystal is doped to produce an n-type

region and a p-type region, one above the other, resulting in a p-n junction, or diode.

The means of generating optical gain in a diode laser, the recom- bination of injected

holes and electrons (and consequent emission of photons) in a forward-biased

semiconductor pn junction, represents the direct conversion of electricity to light. This

is a very efficient process, and practical diode laser devices reach a 50-percent

electrical-to-optical power conversion rate, at least an order of magnitude larger than

most other lasers. Over the past 20years, the trend has been one of a gradual

replacement of other laser types by diode laser based–solutions, as the

considerable challenges to engineering with diode lasers have been met. At the

same time the compactness and the low power consumption of diode lasers have

enabled important new applications such as storing information in compact discs and

DVDs, and the practical high-speed, broadband transmission of information over

optical fibers, a central component of the Internet.

4.2 PSD (POSITION SENSITIVE DETECTOR)

Various methods are available for detecting the position of incident light. These

include methods using small discrete detector arrays or multi-element sensors such

as CCD sensors. In contrast to these sensors, PSDs (position sensitive detectors)

are comprised of a monolithic detector with no discrete elements and provide

continuous position data by making use of the surface resistance of the photodiode.

PSDs offer advantages such as high position, resolution, high speed response and

reliability. .A PSD basically consists of a uniform resistive layer formed on one or

both surfaces of a high-resistivity semiconductor substrate, and a pair of electrodes

formed on both ends of the resistive layer for extracting position signals. The active

area, which is also a resistive layer, has a PN junction that generates photocurrent

by means of photovoltaic effect.

Fig.4.1 PSD Structural view

4.3 STEPPER MOTOR

Stepper motors provide a means for precise positioning and speed control without

the use of feedback sensors. The basic operation of a stepper motor allows the shaft

to move a precise number of degrees each time a pulse of electricity is sent to the

motor. Since the shaft of the motor moves only the number of degrees that it was

designed for when each pulse is delivered, you can control the pulses that are sent

and control the positioning and speed. The rotor of the motor produces torque from

the interaction between the magnetic field in the stator and rotor. The strength of the

magnetic fields is proportional to the amount of current sent to the stator and the

number of turns in the windings. The stepper motor uses the theory of operation for

magnets to make the motor shaft turn a precise distance when a pulse of electricity

is provided. You learned previously that like poles of a magnet repel and unlike poles

attract. Figure 1 shows a typical cross-sectional view of the rotor and stator of a

stepper motor. From this diagram you can see that the stator (stationary winding)

has eight poles, and the rotor has six poles (three complete magnets). The rotor will

require 24 pulses of electricity to move the 24 steps to make one complete

revolution. Another way to say this is that the rotor will move precisely 15° for each

pulse of electricity that the motor receives. The number of degrees the rotor will turn

when a pulse of electricity is delivered to the motor can be calculated by dividing the

number of degrees in one revolution of the shaft (360°) by the number of poles

(north and south) in the rotor. In this stepper motor 360° is divided by 24 to get

15°.When no power is applied to the motor, the residual magnetism in the rotor

magnets will cause the rotor to detent or align one set of its magnetic poles with the

magnetic poles of one of the stator magnets. This means that the rotor will have 24

possible detent positions. When the rotor is in a detent position, it will have enough

magnetic force to keep the shaft from moving to the next position. This is what

makes the rotor feel like it is clicking from one position to the next as you rotate the

rotor by hand with no power applied.

Fig 4.2. Diagram that shows the position of the six-pole rotor and eight-pole stator of

a typical stepper motor. When power is applied, it is directed to only one of the stator

Focused laser spot falling on 1st

quadrant 0f duo-lateral PSD

Focused laser spot falling on1st

quadrant 0f pincushion PSD

pairs of windings, which will cause that winding pair to become a magnet. One of the

coils for the pair will become the North Pole, and the other will become the South

Pole. When this occurs, the stator coil that is the North Pole will attract the closest

rotor tooth that has the opposite polarity, and the stator coil that is the South Pole will

attract the closest rotor tooth that has the opposite polarity. When current is flowing

through these poles, the rotor will now have a much stronger

attraction to the stator winding, and the increased torque is called holding torque.

By changing the current flow to the next stator winding, the magnetic field will be

changed 45°. The rotor will only move 15° before its magnetic fields will again align

with the change in the stator field. The magnetic field in the stator is continually

changed as the rotor moves through the 24 steps to move a total of 360°. Figure 2

shows the position of the rotor changing as the current supplied to the stator

changes.

``

AB

C

DA'

B'

C'

D'

AB

C

DA'

B'

C'

D'

`

AB

C

DA'

B'

C'

D'

`

AB

C

DA'

B'

C'

D'

15°

`

AB

C

DA'

B'

C'

D'

30°

45°

60°

Current is applied to the A and A’ windings so the A winding is north

Current is applied to the B and B’ windings so the B winding is north

Current is applied to the C and C’ windings so the C winding is north

Current is applied to the D and D’ windings so the D winding is north

Current is applied to the A and A’ windings so the A’ winding is north

Rotor

A A’B B’C C’D D’

V

Fig 4.2. shows the position of the six-pole rotor and eight-pole stator of a typical

stepper motor.

In fig 4.2. Movement of the stepper motor rotor as current is pulsed to the stator. (a)

Current is applied to the A and A’ windings, so the A winding is north, (b) Current is

applied to B and B’ windings, so the B winding is north, (c) Current is applied to the

C and C’ windings, so the C winding is north, (d) Current is applied to the D and D’

windings so the D winding is north. (e) Current is applied to the A and A’ windings,

so the A’ winding is north.

In Fig.4.2(a) you can see that when current is applied to the A and A’ stator

windings, they will become a magnet with the top part of the winding being the North

Pole, and the bottom part of the winding being the South Pole.

You should notice that this will cause the rotor to move a small amount so that one of

its south poles is aligned with the north stator pole (at A), and the opposite end of the

rotor pole, which is the north pole, will align with the south pole of the stator (at A’). A

line is placed on the south-pole piece so that you can follow its movement as current

is moved from one stator winding to the next. In Fig. 4.2(b) current has been turned

off to the A and A” windings, and current is now applied to the stator windings shown

at the B and B’ sides of the motor. When this occurs, the stator winding at the B’

position will have the polarity for the south pole of the stator magnet, and the winding

at the B position will have the north-pole polarity. In this condition, the next rotor pole

that will be able to align with the stator magnets is the next pole in the clockwise

position to the previous pole. This means that the rotor will only need to rotate 15° in

the clockwise position for this set of poles to align itself so that it attracts the stator

poles.

In Fig. 4.2(c) you can see that the C and C’ stator windings are again energized, but

this time the C winding is the north pole of the magnetic field and the C’ winding is

the south pole. This change in magnetic field will cause the rotor to again move 15°

in the clockwise position until its poles will align with the C and C’ stator poles.You

should notice that the original rotor pole that was labeled 1 now moved three steps in

the clockwise position.

In Fig.4.2(d) you can see that the D and D’ stator windings are energized, the

winding at D position is the north pole. This change in polarity will cause the rotor to

move another 15° in the clockwise direction. You should notice that the rotor has

moved four steps of 15° each, which means the rotor has moved a total of 60° from

its original position. This can be verified by the position of the rotor pole that has the

line on it, which is now pointing at the stator winding that is located in the 2 o'clock

position.

In Fig.4.2(e) you can see that the A and A’ stator windings are energized, the

winding at A position is the south pole. This change in polarity will cause the rotor to

move another 15° in the clockwise direction. You should notice that the rotor has

moved four steps of 15° each, which means the rotor has moved a total of 75° from

its original position. Thus the sequence of energizing ABCDA will move the rotor in

the clockwise direction.

4.4 DIGITAL ENCODER

A digital optical encoder is a device that converts motion into a sequence of digital

pulses. By counting a single bit or by decoding a set of bits, the pulses can be

converted to relative or absolute position measurements. Encoders have both linear

and rotary configurations, but the most common type is rotary. Rotary encoders are

manufactured in two basic forms:

Fig 4.3 Rotatory Digital Encoder

the absolute encoder where a unique digital word corresponds to each rotational

position of the shaft, and the incremental encoder, which produces digital pulses as

the shaft rotates, allowing measurement of relative position of shaft. Most rotary

encoders are composed of a glass or plastic code disk with a photographically

deposited radial pattern organized in tracks. As radial lines in each track interrupt the

beam between a photoemitter-detector pair, digital pulses are produced.

Absolute encoder

The optical disk of the absolute encoder is designed to produce a digital word that

distinguishes N distinct positions of the shaft. For example, if there are 8 tracks, the

encoder is capable of producing 256 distinct positions or an angular resolution of

1.406 (360/256) degrees. The most common types of numerical encoding used in

the absolute encoder are gray and binary codes. To illustrate the acion of an

absolute encoder, the gray code and natural binary code dsisk track patterns for a

simple 4-track (4-bit) encoder are illustrated in Fig 4.4 and 4.5.The linear patterns

and associated timing diagrams are what the photodetectors sense as the code disk

circular tracks rotate with the shaft. The output bit code for both coding schemes are

listed in tables below.

Fig4.4 4bit gray code absolute encoder disk track patterns

Fig4.4 4bit binary code absolute encoder disk track patterns

Decimal code Rotation range (deg.) Binary code Gray code

0 0-22.5 0000 0000

1 22.5-45 0001 0001

2 45-67.5 0010 0011

3 67.5-90 0011 0010

4 90-112.5 0100 0110

5 112.5-135 0101 0111

6 135-157.5 0110 0101

7 15.75-180 0111 0100

8 180-202.5 1000 1100

9 202.5-225 1001 1101

10 225-247.5 1010 1111

11 247.5-270 1011 1110

12 270-292.5 1100 1010

13 292.5-315 1101 1011

14 315-337.5 1110 1001

15 337.5-360 1111 1000

Table 4.1-Bit gray and natural binary codes

The gray code is designed so that only one track (one bit) will change state for each

count transition, unlike the binary code where multiple tracks (bits) change at certain

count transitions. This effect can be seen clearly in Table 4.1. For the gray code, the

uncertainty during a transition is only one count, unlike with the binary code, where

the uncertainty could be multiple counts.

Since the gray code provides data with the least uncertainty but the natural binary

code is the preferred choice for direct interface to computers and other digital

devices, a circuit to convert from gray to binary code is desirable. Figure 4 shows a

simple circuit that utilizes exclusive OR gates (XOR) to perform this function.For a

gray code to binary code conversion of any number of bits N, the most signficant bits

(MSB) of the binary and gray code are always identical, and for each other bit, the

binary bit is the exlcusive OR (XOR) combination of adjacent gray code bits.

4.5 SOLID STATE RELAY (SSR)

A solid state relay (SSR) is an electronic switch, which, unlike an electromechanical

relay, contains no moving parts. The types of SSR are photo-coupled SSR,

transformer-coupled SSR, and hybrid SSR. A photo-coupled SSR is controlled by a

low voltage signal which is isolated optically from the load. The control signal in a

photo-coupled SSR typically energizes an LED which activates a photo-sensitive

diode. The diode turns on a back-to-back thyristor, silicon controlled rectifier, or

MOSFET transistor to switch the load.

Fig 4.5 Solid State Relay (SSR)

Benefits of Solid State Relays

SSRs are a faster alternative to electromechanical relays because their

switching time is dependent on the time required to power the LED on and off

- approximately 1 ms and 0.5 ms respectively. Because there are no

mechanical parts, their life expectancy is higher than an electromechanical

relay.  

4.6 PCI - 1710 DATA ACQUISITION CARD

The PCI-1710 is a multi-function data acquisition card for the PCI bus. Advanced

circuitry allows the user to utilize measurement and control functions such as 12-bit

A/D conversion, D/A conversion, digital input, digital output, and counter/timer. The

card features an automatic channel/gain scanning circuit. The circuit (rather than

your software) controls multiplexer switching during sampling.The on-board SRAM

stores different gain values and configurations for each channel. This design lets you

perform multi-channel high-speed sampling (up to 100 kHz) with different gains for

each channel and with free combination of single-ended and differential inputs.The

PCI-1710 has an on-board FIFO buffer, which can store up to 4 kA/D samples. An

interrupt is generated when the FIFO is half full providing continuous high-speed

data transfer and more predictable performance on Windows systems

Fig4.6 PCI 1710 Card

MAIN FEATURES

16 single-ended or 8 differential or a combination of analog inputs.

12-bit A/D converter, with up to 100 kHz sampling rate

Programmable gain.

Automatic channel/gain scanning.

Onboard FIFO memory (4096 samples).

Two 12-bit analog output channels (PCI-1710/1710HG only)

4.7 DMC MOTION CONTROLLER

The DMC-18x2 Econo Series are PCI bus motion controllers designed for the most

cost-sensitive applications. The DMC-18x2 controllers accommodates 1- through 4-

axis formats and allows control of step or servo motors on any combination of axes.

Any mode of motion can be programmed including linear and circular interpolation,

contouring, electronic gearing and ecam.

To minimize cost, the following features are not available on the DMC-18x2: five

through eight axes of control, optical isolation on inputs, uncommitted analog inputs,

dual encoder inputs, and the auxiliary FIFO and DPRAM communication channel. If

you need these features, select the DMC-18x 6 Accelera PCI controllers.

Like all Galil controllers, programming the DMC-18x2 is simplified with two-letter,

intuitive commands and a full set of software tools such as GalilTools for servo

tuning and analysis

4.8 GALIL TOOLS

GalilTools is Galil's set of software tools for current Galil controllers. It is highly

recommended for all first-time purchases of Galil controllers as it provides easy set-

up, tuning and analysis. GalilTools replaces the WSDK Tuning software with an

improved user-interface, real-time scopes and communications utilities.

The Galil Tools set contains the following tools: Scope, Editor, Terminal, Watch and

Tuner, and a Communication Library for development with Galil Controllers.The

powerful Scope Tool is ideal for system analysis as it captures numerous types of

data for each axis in real-time. Up to eight channels of data can be displayed at

once, and additional real-time data can be viewed by changing the scope settings.

This allows literally hundreds of parameters to be analyzed during a single data

capture sequence. A rising or falling edge trigger feature is also included for precise

synchronization of data.

The Program Editor Tool allows for easy writing of application programs and multiple

editors to be open simultaneously.The Terminal Tool provides a window for sending

and receiving Galil commands and responses.The Watch Tool displays controller

parameters in a tabular format and includes units and scale factors for easy

viewing.The Tuning Tool helps select PID parameters for optimal servo performance.

The Communication Library provides function calls for communicating to Galil

Controllers with C++ (Windows and Linux) and COM enabled languages such as VB

C#, and Labview (Windows only).GalilTools also runs on Windows and Linux

platforms.

4.9 LAB VIEW

LabVIEW stands for Laboratory Virtual Instrumentation Environment Workbench.

LabVIEW is a program development application much like C or BASIC development

systems, however LabVIEW is different from those applications in respect that it

uses graphical programming language instead of text space languages to create

programs and block diagram form. LabVIEW uses terminology, icons and ideas

familiar to scientists and engineers and relies on graphical symbols rather than

textual language to describe programming action. LabVIEW has extensive libraries

of function and sub routines for most programming tasks. LabVIEW contains

application specific libraries for data acquisition, data analysis and instrument

control. LabVIEW includes conventional tools so programmer can set break points ,

animate program execution to see the data flow during execution and single step

through the program to make debugging and program development easier. LabVIEW

programs are called virtual instruments (VI) because their appearance and operation

imitate actual instruments. VI’s have both an interactive user interface and source

code equivalent and accept parameters from high level VIs. VIs contains interactive

user interface called the front panel because it simulates the panel of physical

instruments. It contains knobs, buttons, graphs and other controls and indicators

VI receives instructions from the block diagram provides pictorial solution to the

programming problem. Block diagram contains the source code for the VI.VI uses

hierarchical architecture and modular programming concepts VI with in a VI is known

as subVI.