project report

PROJECT REPORT

REPORT

On

INDUSTRIAL TRAINING AT

BHARAT ELECTRONICS LIMITED,

GHAZIABAD

SUBMITTED BY:

VRISHTY GARG

ROLL NO.-27116

ELECTRONICS AND COMM. ENGG.

UIET,CSJMU,KANPUR.

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BHARAT ELECTRONICS LIMITED

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Trainee No. 246/10

CONTENTS

1. PREFACE

2. ACKNOWLEDGEMENT

3. CERTIFICATE

4. ABOUT BEL

5. QUALITY POLICY

6. QUALITY OBJECTIVES

7. ENVIRONMENTAL POLICY

8. INDIAN MARKET

9. JOINT VENTURES

10. VISSION,MISSION & OBJECTIVES

11. MANUFACTURING UNITS OF BEL

12. R & D

13. DESIGN & MANUFACTURING SERVICES

14. NINE UNITS OF BEL AT A GLANCE of 91

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15. FORMATION OF THE UNIT (BEL GHAZIABAD)

16. THE PRODUCT RANGE

17. ORGANISATION

18. VARIOUS DEPARTMENTS OF BEL GHAZIABAD

19. ROTATIONAL TRAINING

20. DEPARTMENTAL WORK

INTRODUCTION

HISTORY OF PCB

PCB MANUFACTURING PROCESS

COMPONENTS OF ATE

TYPES OF ATE SYSTEMS

ANALYST

BOUNDARY SCAN TESTING

LANGUAGES

CONTEXT DEPENDENT PROBING

SIMULATORS

S790

21. CONCLUSION

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PREFACE

With the ongoing revolution in electronics and communication where innovations are taking

place at the blink of an eye, it is impossible to keep the pace with the emerging trends.

Excellence is an attitude that the whole of the human race is born with. It is the

environment that makes sure that whether the result of this attitude is visible or otherwise. A

well planned, properly executed and evaluated project training helps a lot in inculcating a

professional attitude. It provides a linkage between the student and industry to develop an

awareness of industrial approach to problem solving, based on a broad understanding of

process and mode of operation of organization.

During this period, the students get the real, first experience for working in the actual

environment. Most of the theoretical knowledge that has been gained during the course of

their studies is put to test here. Apart from this, the students get an opportunity to learn the

latest technology, which immensely helps them in building their career.

Project training has become and important part in students’ curriculum as it not only

makes them aware of the working conditions of any industry, it also helps them in bridging

the gap that exists between an institution and an industry. The project training is of high

importance in helping him psychologically for the transformation.

I had the opportunity to have a real experience on many ventures, which increased

my sphere of knowledge to a great extent. I got a chance to learn many new technologies and

was also interfaced to many new instruments.

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BEL Ghaziabad, a premier electronics company also gives opportunity to students of

many disciplines in helping him/her prepare for the big jump. They conduct training for

organization, which excel in their own fields of operation.

ACKNOWLEDGEMENT

I would like to take this opportunity to thank our Director, Prof. Renu Jain under whose able

guidance our batch was guided to undergo an Industrial training of six weeks for academic

purposes.

This training at the BEL, Ghaziabad gave me immense opportunities to widen my horizon of

knowledge and to further increase the depth of concepts involved in the field of

Communication equipments used in defense sector. I would like to express my extreme

gratitude towards Human Resource Department who allowed me to join BEL as a trainee. I

would also like to mention the generosity in delivering every possible help by the Testing

Department employees.

I also take this opportunity to express my sincere thanks and deep gratitude to all the

members of the ATE Deptt. of BHARAT ELECTRONICS LIMITED, GHAZIABAD. All of

them were extremely cooperative and helping. They have been very supportive of my work

with their encouragement and criticism. I am deeply indebted to:

1. Mrs. Anuradha Mahur (Manager, ATE Deptt.)

2. Ms. Tanuja (D.E., ATE Deptt.)

for allowing me to join their department and guiding me throughout the project.

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Yours sincerely,

Vrishty Garg

CERTIFICATE

This is to certify that the project report entitled AUTOMATED TEST EQUIPMENT

(TESTING OF PCB) submitted by VRISHTY GARG from UIET,CSJMU,KANPUR for the

degree of B.Tech. is bonafide work done by her in BHARAT ELECTRONICS LIMITED,

GHAZIABAD from 7 JUNE , 2010 to 17 JULY,2010. She has worked under my guidance

and supervision in this organization.

I hereby certify her project report and approve it.

PROJECT GUIDES

Ms. Tanuja Mrs. Anuradha Mahur

D.E. (Radar-ATE) DGM (Radar-ATE)

BEL, GHAZIABAD BEL, GHAZIABAD

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INTRODUCTIONINTRODUCTION TO BELTO BEL

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ABOUT BEL

Bharat Electronics Limited (BEL) was established in 1954 as a Public Sector Enterprise

under the administrative control of Ministry of Defense as the fountainhead to manufacture

and supply electronics components and equipment. In the past 50 years this unit has

augmented into an organization having nine units and employing about 12000 employees. A

good range of products is being manufactured in these units in vital areas like Defense,

communications, system engineering etc. Initially Defense consumed products, but now they

are available in commercial market and for export also. BEL, with a noteworthy history of

pioneering achievements, has met the requirement of state-of-art professional electronic

equipment for Defense, broadcasting, civil Defense and telecommunications as well as the

component requirement of entertainment and medical X-ray industry. Over the years, BEL

has grown to a multi-product, multi-unit, and technology driven company with record of

accomplishment of a profit earning PSU.

The company has a unique position in India of having dealt with all the generations of

electronic component and equipment. Having started with a HF receiver in collaboration with

T-CSF of France, the company's equipment designs have had a long voyage through the

hybrid, solid-state discrete component to the state of art integrated circuit technology.

In the component arena also, the company established its own electron valve manufacturing

facility. It moved on to semiconductors with the manufacture of germanium and silicon

devices and then to the manufacture of Integrated circuits. To keep in pace with the

component and equipment technology, its manufacturing and product assurance facilities

have also undergone sea change. The design groups have CADDs facility, the manufacturing

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has CNC machines and a Mass Manufacture Facility, and Quality Control (QC) checks are

performed with multi-dimensional profile measurement machines, Automatic testing

machines, environmental labs to check extreme weather and other operational conditions. All

these facilities have been established to meet the stringent requirements of MIL grade

systems.

Today’s BEL’s infrastructure is spread over nine locations with 29 production divisions

having ISO-9001/9002 accreditation. Product mix of the company are spread over the entire

electro-magnetic spectrum ranging from tiny audio frequency semiconductor to huge radar

systems and X-ray tubes on the upper age of the spectrum. It’s manufacturing units have

special focus towards the product ranges like Defense Communication, Radar’s, Optical and

Optoelectronics, Telecommunications, Sound and Vision Broadcasting, Electronic

components etc.

BEL has nurtured and built a strong in-house R&D base by absorbing technologies from

more than 50 leading companies worldwide and DRDO Labs for a wide range of products. A

team of more than 800 engineers is working in R&D. Each unit has its R&D Division to

bring out new products to the production lines. Central Research Laboratory (CRL) at

Bangalore and Ghaziabad works as independent agency to undertake contemporary design

work on state-of-art and futuristic technologies. About 70% of BEL's products are of in-

house design.

BEL was among the first Indian companies to manufacture computer parts and peripherals

under arrangement with International Computers India Limited (ICIL) in 1970s. BEL

assembled a limited number of 1901 systems under the arrangement with ICIL. However,

following Government's decision to restrict the computer manufacture to ECIL, BEL could

not progress in its computer manufacturing plans. As many of its equipment were

microprocessor based, the company continued to develop computers based application, both

hardware and software. Most of its software requirements are in real time. EMCCA, software

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intensive naval ships control and command system is probably one of the first projects of its

nature in India and Asia.

BEL has won a number of national and international awards for Import Substitution,

Productivity, Quality, and Safety Standardization etc. BEL was ranked no. 1 in the field of

electronics and 46th overall among the top 1000 private and public sector undertakings in

India by the Business Standard in it’s special supplement “The BS 1000 (1997-98)”. BEL

was listed 3rd among the mini Ratanas (category II) by the government of India, 49 th among

Asia’s top 100 Electronic companies by the Electronic Business Asia and within the top100

worldwide Defense Companies by the Defense News, USA.

MILESTONES

YEAR MILESTONES

2007 BEL conferred the Navratna status

2007 BEL gets AS 9100B certification

2003 BEL celebrates its Golden Jubilee Year

2002 BEL acquires category-I Mini Ratna status

2002 Foundation Stone laid for BEL’s new corporate office building in

Bangalore

2001 BEL bags National R&D Award in Electronics Industry Sector

2000 Bangalore unit of BEL implements Rain Water Harvesting on an industrial

basis

1999 Bharat Electronics Quality institute was established

1998 Hyderabad unit gets ISO 9002

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Kotdwara unit gets ISO 9001

1996 Joint venture with Multitone and GEMS

1994 ISO-9001 Accredation

1993 ISO-9002 Accredit ion

1992 Central research laboratory, Ghaziabad was established

1991 SATCOM

1990 EMI/EMC Test Facilities & Computer Software

1989 Telecom-Switching &Transmission System and Mass Mfg. Facility

1988 Central Research LABORATORY, Bangalore was established

1987 Naval Equipment Division

1986 Kotdwara, Taloja & Hyderabad units. Klystrons & Travelling wave tubes.

1985 Madras and Panchkula units, Broadcast & TV, Digital Communication

Equipment Divisions, Vacuum Interrupters

1983 (ASCO) Machilipatnam integrated with BEL

1982 Space Electronics Divisions

1979 Pune unit was established

1974 Ghaziabad unit was established

1972 B/W TV Picture Tubes

1971 Integrated Circuits and Hybrid Microcircuits

1970 X-ray Tubes & Management

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1968 HF& Broadcast Equipment, Silicon Semiconductors

1967 Transmitting Tubes

1966 Radars

1962 Germanium Semiconductors

1961 Receiving Valves

1956 Equipment Production started at Bangalore (present LPE Division)

1954 Incorporation of BEL

QUALITY POLICY

Bharat Electronics consistently delivers enhanced value to its customers, through continual

improvement of its products and processes.

QUALITY OBJECTIVES

Quality objectives of Bharat Electronics are as follows: -

Effective and efficient design and development process, considering the present and

Future needs of customers.

Enhanced customer satisfaction by in-time delivery of defect free products And

Effective Life cycle support.

Continual up gradation and utilization of infrastructure and human sources.

Mutual beneficial alliances with suppliers.

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Continual improvement of processes through innovation, technology and knowledge

management.

ENVIRONMENTAL POLICY

Bharat Electronics is involved in the design, development, production and supply of

professional electronic equipments and services with a Corporate Mission “to be the market

leader in Defense Electronics and other chosen fields and products.” It recognizes the impact

of our day-to-day operations on the environment. In order to minimize the harmful effects on

the environment by such operations, it commits itself to: -

Continual improvement of our environmental performance and prevention of

pollution, reduction of waste and consumption of resources (materials, water, fuel &

energy) in all our operations, by implementing and maintaining an Environmental

Management System.

Minimize any significant environmental impact of all our activities, products and

processes throughout their life cycle, by applying the most economically viable

application of the best available technology for prevention of pollution.

Set, maintain and review environmental objectives and targets as well as develop

environmental performance evaluation procedures and associated indicators.

Complete with all the relevant legislations, regulations and industry codes associated

with our environmental impacts and where no legislation exists, endeavor to set

appropriate standards.

Promote environmental awareness among all employees and ensure their participation

in implementing this environmental policy at their place of work. Suppliers will also

be made aware of the need to preserve environment and prevent pollution, in line

with the company’s environmental policy.

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Effective and efficient design and development process, considering the present and

future needs of the customers.

Enhanced customer satisfaction by on time delivery of defect free products and

effective lifecycle support.

Continuous up gradation and utilization of infrastructure and human resources.

Mutually beneficial alliances with supplies.

Continual improvement of processes through innovation, technology and knowledge

management.

INDIAN MARKET

Bharat Electronics Limited is a major supplier of products and turnkey systems to the Indian

Defense Services. Over the years, BEL has diversified into manufacturing many civilian

products as well. Large turnkey telecommunication solutions are also being offered to

civilian market. A brief list of the Customers in the defense and civilian market segments and

the products and services offered to them is given below:

Products and Services Customers

Defense Communication

Radars & Sonars

Indian Defense Services , Para -military forces

Indian Defense Services, Civil Aviation, Meteorological

Department, Space Department

Telecommunication Department of Telecommunication, Para- military forces,

Power Sector, Oil Industry, Railways

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Broadcasting Equipments and

Studio Systems

All India Radio, Doordarshan, (National Radio & TV

Broadcasters)

Electronic Voting Machine Election Commission Of India

Solar Products & Systems Individuals, Private and Government Organizations

Turnkey Systems, E-

Governance Networks

Police, State Governments, Public Sector Undertakings

Components All India Radio and Doordarshan the National Radio &

TV Broadcasters, Instrumentation Industry, Switching

Industry, Entertainment Industry, Telephone Industry

JOINT VENTURES

GE-BE PRIVATE LIMITED

GEBE Pvt. Limited was set up in 1997 as a joint venture between Bharat Electronics Limited

and General Electric Medical System. The facility based at Whitefield, Bangalore, India,

manufactures X-ray tubes for RAD & F and CT systems, as well as components such as High

Voltage Tanks and Detector modules for CT system. The products are exported worldwide

and meet the safety and regulatory standards specified by FDA, CE, MHW, AERB and the

facility has been accredited with ISO-9001; ISO-13485 and ISO-14001 certifications.

GEBEL also markets the conventional X-ray tubes made at Pune Unit of BEL.

The turnover of GEBEL during 2004-2005 was over Rs.450 Crores including an export of

over Rs.430 Crores.

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X-RAY TUBES

HIGH VOLTAGE TANKS

CT DETECTOR MODULES

The company has been recognized for its outstanding export performance since 1998 by the

Export Promotion Councils. The facility conforms to the high standards of Environment,

Health & Safety and is recognized as a GE Global Star site. Apart from manufacturing, a

dedicated engineering team is working on the development of new technologies & products

to meet various customer needs.

BEL-MULTITONE:

BEL and Multitone, UK offers state-of-the-art Mobile Communication Products for the

workplace. Multitone invented paging in 1956 when it developed the world’s first system to

serve the “life or death” environment of St. Thomas Hospital, London. With the strength of

Bharat Electronics in the Radio Communications field and the technology of multitone in the

field of Radio Paging, the joint venture company is in a position to offer tailor made

solutions to the Mobile Communication needs at workplaces in various market segments.

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The joint venture offers one of the most comprehensive on-site product ranges- from small,

easy to use pagers to practical, durable private mobile radios and the latest technology, digital

cordless communication systems. Brief details of the products are:

Access 700 one-way speech paging system which supports 100 pagers.

Access 1000/3000 Radio Paging system which supports 1500/5000 users.

Computer Radio Integration units.

Digital Cordless Communication Systems.

VISION, MISSION,VALUES AND OBJECTIVES

VISION

- To be a world-class enterprise in professional electronics.

MISSION

- To be a customer focused, globally competitive company in defense electronics and in

other chosen areas of professional electronics, through quality, technology and innovation.

VALUES

- Putting customers first.

- Working with transparency, honesty & integrity.

- Trusting and respecting individuals.

- Fostering team work.

- Striving to achieve high employee satisfaction.

- Encouraging flexibility & innovation.

- Endeavouring to fulfill social responsibilities.

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- Proud of being a part of the organization.

OBJECTIVES

- To be a customer focussed company providing state-of-the-art products & solutions at

competitive prices, meeting the demands of quality, delivery & service.

- To generate internal resources for profitable growth.

- To attain technological leadership in defense electronics through in-house R&D,

partnership with defense/research laboratories & academic institutions.

- To give thrust to exports.

- To create a facilitating environment for people to realize their full potential through

continuous learning & team work.

- To give value for money to customers & create wealth for shareholders.

- To constantly benchmark company's performance with best-in-class internationally.

- To raise marketing abilities to global standards.

- To strive for self-reliance through indigenization

MANUFACTURING UNITS OF BEL

BEL originated in 1954 with a factory of Jallahali, since then Bharat Electronics has grown

into nine units all over India and two overseas offices located at New York and Singapore.

BEL provides most of its services to defense sector. 85% work is done for defense services

and the rest 15% work is done for public services. A brief description of the units and their

products is given below:-

1. Bangalore

This is also called BG complex. Jallahali unit, which is the mother unit, is now a part of the

BG complex. This is the biggest unit with the strength of approximately 9000-10000

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employees working here. It was the first Radar manufacturing company. Among the

products produced here the important ones are:

Communication Equipments.

OB VAN for Doordarshan and other channels for live coverage and telecast etc.

RADAR-mobile, one dimensional, 3 dimensional and multi dimensional RADAR.

Different range of semi conductor devices like ICs, Resistors, Black & White and

Color TV picture tube glasses.

2. Ghaziabad

This unit was set up in 1974, and approximately 2500 employees are working here. This is

the second largest unit of BEL. It basically manufactures:

RADAR

Communication equipments like antennae etc.

SATCOM (defense)

Microwave components

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3. Pune

To diversify further one more branch was added in the year 1979 in Pune. In this branch

around 700-800 employees are working. The product profile includes:

X ray tubes

Batteries

Electro-optics

4. Machilipatnam

There was one Andhra Scientific company, which was a sick unit. This was taken over by

BEL and is called ASCO unit in 1983. The products include:

Optical and Opto-electronic equipments like binoculars, microscopes etc.

Medical electronics

5. Taloja

This is an industrial place near Bombay. This unit manufactures:

Glass shells for black and white TV picture tubes

Shelter for electronic equipments

Train actuated warning system

Electronic equipment assembly

6. Panchkula

The government in 1985 proposed Panchkula and Kotdwara simultaneously. It was proposed

to set up one unit each in Haryana and Uttar Pradesh. But the place in UP for setting up BEL

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unit could not be decided while that at Haryana was decided and hence this unit started

earlier. This unit manufactures:

Communication equipments like VHF, UHF transceivers etc.

7. Kotdwara

This is a unit in Garhwal District of Uttaranchal. This unit manufactures radio relay,

Multiplex equipments and exchanges etc.

8. Chennai

The eight unit of BEL was established in Chennai. This unit manufactures tank electronics

related equipments and Optical fire control system.

9. Hyderabad

This is another unit of BEL, which manufactures electronics warfare equipments.

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Besides these manufacturing units, there are marketing centers at Delhi, Mumbai,

Vishakhapatnam, and license cell at Agra, Overseas offices at New York and Singapore.

RESEARCH & DEVELOPMENT

Research and Development is a key focus activity at BEL. Research & Development started

in 1963 at BEL and has been contributing steadily to the growth of BEL's business and self-

reliance in the field of defence electronics and other chosen areas of professional electronics.

BEL's R&D Policy is to enhance the company's pre-eminence in defence electronics and

other chosen fields and products through Research & Development. Major R&D objectives

of BEL is development of new products built with cutting-edge technology modules to meet

customer requirements ensuring that the developed products are state-of-the-art, competitive

and of the highest quality .

Resources and Investments

All the 9 manufacturing Units of BEL have their own Development & Engineering (D&E)

divisions. The role of these D&E divisions is to develop new products and obtain customer

acceptance, generate new business, provide product lifecycle support and upgrades, develop

processes and components as necessary.

Specialised core technology modules required by the D&E Engineers for product

development are developed at several core Central D&E groups at Bangalore. BEL also has

two Central Research Laboratories (CRLs) located at Bangalore and Ghaziabad, whose

primary role is to work on critical areas of technology, develop enabling technology modules

for use by D&E divisions and provide training to D&E engineers on emerging technologies.

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Presently there are about 1450 engineers and 300 support staff in the R&D Divisions of BEL,

concentrating on various projects. D&E divisions of BEL pursue various categories of

projects: in-house development projects, joint development or ToT projects with DRDO /

other national design agencies and ToT or joint development projects with foreign vendors.

Usually, 45 to 60% of the turnover is from BEL designed products, 10 to 25% of turnover is

from products designed by DRDO and other National Design Agencies and the remaining

from foreign collaborations.

The annual R&D expenditure is around 4 to 5% of BEL's sales turnover. BEL regularly

recruits young engineers based on the identification of required competencies for the R&D

divisions. There are schemes for on-the-job training after placement and facilities for

continuous learning for these engineers. There are recognition and reward schemes for

excellence among R&D engineers.

BEL R&D units are recognised by the Department of Scientific & Industrial Research

(DSIR) under the Ministry of Science and Technology, Government of India. BEL's

Software Technology Centre at Bangalore has the recognition of Capability Maturity Model

(CMM) Level 5 Rating from Software Engineering Institute (SEI).

Areas of R&D Activity

R&D engineers are engaged in the development of new products, cutting edge technology

modules, subsystem, processes & components in the following major areas:-

- Radars

- Sonars & Naval Systems

- Communications

- Command Control Systems

- Electronic Warfare Systems & Avionics

- Tank and Opto-electronics

- Broadcast, Satcom & Telecom

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- Other products & systems

- Components

Core Central Groups under Central D&E support the product development groups with state-

of-the-art technology modules in areas like Power Amplifier, Power Supply, RF &

Synthesiser, Crypto, DSP & Datacom, Software and Radar Signal Processing.

DESIGN & MANUFACTURING SERVICES

Bharat Electronics Limited today has an integrated approach and systems capability, which is

a direct result of its commitment to providing tailor-made solutions to the customers through

its philosophy of quality management.

The company has set up impressive infrastructure and manufacturing

facilities spread over nine ISO 9001 / 9002 certified modern production units around the

country. The infrastructure is regularly upgraded with the latest and state-of-the-art facilities.

Manufacturing infrastructure is amply supported by the applicable Quality Assurance

infrastructure and skilled technicians. Standards Division of BEL optimizes the processes on

a continuous basis. Process and QA standards generated by BEL are used as reference by a

number of companies in India.

With the strengths in infrastructure and skilled/experienced manpower, BEL offers

Contract Manufacturing Services for both domestic and international customers in the

following areas:

PCB Assembly(SMT, Through Hole, BGA) and Testing

BEL has set up an exclusive Mass Manufacturing Facility and achieved proficiency in

assembly of a wide variety of circuit board designs including Surface Mount Technology

(SMT), Mixed Technology and Plated / Pin Through Hole Technology (PTH),. BEL also

offers most modern facilities for testing of the products manufactured.

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BEL has the experience and expertise in the manufacture of high Precision Machined and

Fabricated Parts in its state-of-the-art facilities equipped with latest CNC and special purpose

machines. Products manufactured include chassis, enclosures, panels, brackets, rack mounts,

card cage flanges and covers, large and medium modular frames and precision machined

parts for the electronic, computer, and electrical products being used in commercial, defense,

aerospace and telecommunication industries.

Opto Electronic Components and Assemblies

Bharat Electronics offers cost effective services for design and manufacture of optical and

opto-electronic products and components operating in the UV, Visible and IR spectrum.

Optical components include lenses, prisms, mirrors, windows, wedges etc. and Optical

assemblies include Objective assembly, Eye piece assembly, Collimator assembly & Imaging

assembly.

Microwave Integrated Circuit Assemblies

BEL manufactures a variety of Microwave Components and sub-systems using microchip

technology which are required for wide range of applications in communication, radar

systems including airborne and space related sub-systems. The facility is also qualified for

the manufacture of C-Band Receiver for satellite systems.

Multilayer PCB Design and Manufacturing

BEL has established an excellent infrastructure to manufacture variety of Printed Circuit

Boards ranging from single sided to 18 layers. The facilities are equipped to manufacture

high technology quick turn prototypes, "Quick-to-Market products" and undertake volume

production of buried and blind vias, build-up multi layers (microvias) and ultra fine

lines/spaces.

Cable Assemblies And Wiring Harnesses

BEL specializes in the manufacture of cable assemblies and builds custom wiring harness

required for its electronic equipment for commercial and military applications.

Design And Manufacturing Of Professional Grade Transformers, Coils And Sub-

Assemblies

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BEL manufactures a wide range of transformers (power, audio frequency, modulation, pulse,

filament etc.,) coils (audio frequency, radio frequency, air arc, IF, pot case, moulded, etc.,)

Chokes (smoothing, modulation, radio frequency, etc.,) and Sub-assemblies (HV Units, EHV

units, etc.). Most of these products meet the stringent defense specifications for use in

defense equipment.

Antenna Manufacturing

Bharat Electronics Limited is engaged in development and production of various types of

antennas for use in Radars, Communications, TV-Broadcasting, Satellite Communication etc.

The antenna production division also includes a FRP shop capable of producing antennas

with hand-lay-up technology. The R&D and production efforts are supported by well-

equipped microwave testing laboratory and a microwave outdoor antenna test range. There is

also a facility to produce thin film MIC components which are extensively used in phased

array antennas.

Many foreign companies like AT&T-USA, GE-Medical-USA, Vishay-Austria,

ECHOSTAR-USA, ENCON International-USA, CREO Products Inc-Canada., Multitone-

UK, Elisra, Elta, Ortek, Scitex, ELOP-Israel, Technology Rendezvous Inc., USA,

ERICSSON,SWEDEN and many more are using our facility for meeting their outsourcing

requirements.

BEL has also established Joint Venture Companies with Delft, Holland for

Image Intensifier Tube and General Electric Medical Systems, USA for X-Ray Tubes.

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NINE UNITS OF BEL AT A GLANCE

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FORMATION OF THE UNIT-BEL,GHAZIABAD

In the mid 60's, while reviewing the Defense requirement of the country, the government

focused its attention to strengthen the air Defense system, in particular the ground electronics

system support, for the air Defense network. This led to the formulation of a very major plan

for an integrated Air Defense Ground Environment System known as the Plan ADGES with

Prime Minister as the presiding officer of the apex review committee. At about the same

time, Public attention was focused on the report of the Bhabha Committee on the

development and production of electronic equipment. The ministry of Defense immediately

realized the need to establish production capacity for meeting the electronic equipment

requirements for its Plan ADGES.

BEL was then entrusted with the task of meeting the development and production

requirement for the Plan ADGES and in view of the importance of the project it was decided

to create additional capacity at a second unit of the company.

In December 1970 the Govt. sanctioned an additional unit for BEL. In 1971, the industrial

license for manufacture of radar and microwave equipment was obtained; 1972 saw the

commencement of construction activities and production was launched in 1974.

Over the years, the Unit has successfully manufactured a wide variety of equipment needed

for Defense and civil use. It has also installed and commissioned a large number of systems

on turnkey basis. The Unit enjoys a unique status as manufacturer of IFF systems needed to

match a variety of Primary Radars.

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THE PRODUCT RANGE

Radar Systems:

3-Dimensional High Power Static and Mobile Radar for the Air Force.

Low Flying Detection Radar for both the Army and the Air force.

Tactical Control Radar Systems for the Army

Battlefield Surveillance Radar for the Army

IFF Mk-X Radar systems for the Defense and Export

ASR/MSSR systems for Civil Aviation.

Radar & allied systems Data Processing Systems.

Communications:

Digital Static Tropo scatter Communication Systems for the Air Force.

Digital Mobile Tropo scatter Communication System for the Air Force and Army.

VHF, UHF & Microwave Communication Equipment.

Bulk Encryption Equipment.

Turnkey Communication Systems Projects for defense & civil users.

Static and Mobile Satellite Communication Systems for Defense

Telemetry/Tele-control Systems.

Antennae:

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Antennae for Radar, Terrestrial & Satellite Communication Systems.

Antennae for TV Satellite Receive and Broadcast applications.

Antennae for Line-of-sight Microwave Communication Systems.

Microwave Component:

Active Microwave components like LNAs, Synthesizer, Receivers etc.

Passive Microwave components like Double Balanced Mixers, etc

Most of these products and systems are the result of a harmonious combination of technology

absorbed under ToT from abroad, Defense R&D Laboratories and BEL's own design and

development efforts.

ORGANISATION

The operations at BEL Ghaziabad are headed by General Manager with Additional / Deputy

General Manager heading various divisions as follows:

Design & Engineering Divisions :

Development and Engineering-R

Development and Engineering-C

Development and Engineering-Antenna.

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VARIOUS DEPARTMENTS OF BEL GHAZIABAD

● Human Resource Development

● Design and Engineering

● Work Maintenance

● Test Equipment and Automation

● PCB Fabrication

● Quality Control

● Works Assembly

● Design & Development

● Microwave Lab

● Environment and Testing Laboratory

● Personnel and Administration

● Production control

● Management Services

● Information Systems

● Antenna Fabrication

● Machine Shop

● Fabrication Shop

● Finance and Accounts

● Material Management

● Plant and Service

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● Marketing and Customer Co-ordination

● Quality Assurance and Torque

● Central Services

● Central Research Laboratory

ROTATIONAL TRAINING

The first week in the company was the period of orientation. In this period we were told

about functioning of various departments.

Following is the briefing, my experience and observation about various departments of the

company:

PERSONNEL AND ADMINISTRATION

The manager (P&A) has jurisdiction over the following departments:

Establishment

Industrial relations

Welfare section

Medical

Recruitment

Adjudication

H.R.D. department

Security section

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Co-ordination

Hindi cell

ESTABLISHMENT

It deals with the following works:

Promotion of all the employees.

Transfer of employees.

Yearly increment of employees.

Deputation etc.

INDUSTRIAL RELATIONS

The aim of this department is to maintain good relation between the employees and the

management. It is concerned with the maintenance of harmony and discipline within the

factor and removes conflict between the employees and management,

WELFARE

This section deals with:

Canteen facility

Medical facility

Crèche facility

Maternity benefits

Labour welfare funds

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Workers education scheme

Family welfare scheme

Cultural activities

National savings scheme

Community development program

MEDICAL

There is a small hospital that looks after the employees, their family health and provides

medicine.

RECRUITMENT

The employees’ acquisition form is sent by various deptts. to this section. For executives,

there is an entrance examination followed by an interview taken by the cooperate office. For

non executives, the employment exchange forward the name and afterwards, the recruits are

send to HRD for training of one to sixth months.

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HUMAN RESOURCES DEVELOPMENT SECTION

The HRD section controls the under listed functions:

1. Training

Two training programs are:

SDP (Skill development program)

EDP (Employees development program)

2. Development.

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SDPSDP EDPEDP DevelopmentDevelopment

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MICROWAVE INTEGRATED CIRCUITS

Frequencies greater than 1 GHz are termed as Microwaves. Microwave Integrated Circuit

used extensively in production of subsystems for Radar and Communication equipment

constitutes a very important part of technology for these systems are generally imported.

Owing to the crucial and building block nature of the technology involved, BEL is currently

setting up a modern MIC manufacturing facility at a planned expenditure of Rs. 2 crore.

When in full operation this facility will be the main center for the MIC requirements of all

the units of the company.

The manufacturing facility of hybrid microwave components available at BEL Ghaziabad

includes facility for preparation of substrates, assembly of miniaturized components on

substrates, bonding and testing. Testing of these microwave components viz.Directional

couplers, Waveguides, low noise amplifiers, phase shifters, synthesis etc. involve scalar as

well as vector measurements. For this state of the network, analyses are used.

Various losses such as return loss, bending loss, insertion loss are measured and testing is

done in a way to minimize these losses.

MICROWAVE LAB

This section undertakes:

Manufacturing of films and microwave components to meet internal requirements.

Testing of low power antenna for which test-site is about 100 Km from the factory at

Sohna.

The main component testing in this department is:

Oscillators

Amplifiers

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Mixers

Radiation elements (e.g. Feeders)

Microwave components (e.g. Isolators, circulators, waveguides etc.)

Filters (e.g. LPF, BPF, Uniplexers, and Multiplexers etc.)

Functioning of component is listed below:

Frequency response

Noise figure

VSWR

Directivity and coupling

Power measurements

Various instruments in the lab are:

Adaptor

Attenuator

Coupler

Mixer

Detector

ENVIRONMENTAL LAB

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Various tests conducted in the environmental lab in BEL in order to ensure reliability.

Reliability is defined as the probability of a device performing its purpose adequately for the

period intended under the given operating conditions.

In a given system reliability is given as

R = R1 * R2 * R3 ……

The standards available here are:

JSS 55555 - Joint Services Specifications (Military Standard of India)

Mil Standards - U.S. Military standards

QM333 - Civil Aviation and Police

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PCB FABRICATION

PCB is abbreviated form of printed circuit board. As the name suggests, in a PCB the

electrical circuit is printed on a glass epoxy board. This reduces the complex writing network

whose trouble shooting in case of shorting or misconnection is not easy. PCB fabrication is

mostly done for house requirements. It also takes some external jobs.

Types of PCB’s

Single Sided: Having circuit pattern only on one side of the board.

Double Sided: Having circuit pattern on both sides of the board.

Multilayered: Having many layers of circuit.

BEL – Ghaziabad produces only single-sided and double-sided PCB’s.

FABRICATION OF SINGLE SIDED PCB’s:

1. A copper clad sheet is taken. It is cleaned and scrubbed.

2. The sheet is laminated with a photosensitive solution.

3. Positive photo paint of the required circuit is placed over the laminated sheet and it is

subjected to the UV light. As a result the transparent plate gets polymerized and the

opaque part remains unpolymerized.

4. The plate is now dipped in solution in which the non-polymerized part gets dissolved.

5. Tin plating is done on the tracks obtained.

6. Lamination of the plate is removed (stripping).

7. The unwanted copper from the plate is also removed by dipping it in the solution that

dissolves copper but not tin (etching).

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8. Now drilling is done on the paths where the components are to be mounted. This

process fabricates PCB.

PCB MANUFACTURING PROCESS:

1. Copper clad

2. Drill location holes

3. Drill holes for T.H.P. (Through Hole Plating)

4. Clean scrub and laminate

5. Photo print

6. Develop

7. Copper electroplate

8. Tin electroplate

9. Strip film

10. Etch and clean

11. Strip tin

12. L.P.I.S.M. (Liquid Photo Imageable Solder Mask)

13. Photo print

14. Develop

15. Thermal baking

16. Hot air level

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17. Legend marking/Reverse marking

18. Route and clean

But these PCB’s have the following disadvantages:

Due to very narrow spacing between adjacent tracks, there may be a chance of

short circuit if the soldering is done by hands between the components on

opposite side.

Moisture or dust between the gaps may disrupt smooth soldering.

These disadvantages are overcome by soldered mask PCB’s in the later one an additional

film is put on the earlier fabricated PCB, leaving points where components are to be

soldered.

TEST EQUIPMENT & AUTOMATION

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TEST EQUIPMENT SUPPORT (TES)

Main functions are:

Develops technical support to other departments.

Repair of equipment in case of failure.

Maintenance of equipments.

Periodic calibration of equipments.

Provide technical support to other departments. This includes:

Handling requests from the other department for equipments.

Storage of rejected equipments.

Approval of equipments to be purchased.

This section deals with testing and the calibration of electronic equipments only the

standards of this department are calibrated by National Physics Laboratory (NPL).

AUTOMATION TEST EQUIPMENT (ATE)

1. Component testing gives faults of various discrete components of a PCB.

2. Integrated circuits tester tests various IC’s.

3. Functional testing compares output to decide whether the function is being

performed to the desired level of accuracy.

MAGNETICS

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This department manufactures all types of transformers and coils that are used in various

equipments manufactured by BEL. This department basically consists of four sections:

1. Planning section

2. Mechanical section

3. Moulding section

4. Inspection section

The D&E department gives the following descriptions to the magnetics department. They

are as follows:

Number of layers

Number of turns

Type of winding

Gap in core

Insulation between layers

Ac/dc impedance

Dielectric strength

Electrical parameters and

Earthing

The various transformers being made are:

Open type transformer

Oil cooling type transformer of 91

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Moulding type transformer

PCB moulding type transformer

The transformer is mechanically assembled, leads are taken out and checking of specification

is done.

Winding machines are of three types:

Heavier ones- DNR for 0.1 to 0.4 mm diameter

LC controlled machines

Torroidal machines having 32 operations from winding to mechanical assembly.

The various types of windings used are:

Hand winding

Torroidal winding

Sector winding

Pitch winding

Variable pitch winding

Wave winding

Two main types of core used are:

E-type for 3-phase

C-type for single phase

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WORKS ASSEMBLY

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This department plays an important role in the production. Its main function is to assemble

various components, equipment’s and instruments in a particular procedure. It has two

sections, namely:

1. PCB assembly

2. Electronic assembly

In PCB assembly, the different types of PCB are assembled as per BEL standards. PCB is

received from the PCB department on which soldering of component is done either by hand

soldering or wave soldering.

HAND SOLDERING: In case of hand soldering, soldering is done manually.

WAVE SOLDERING: Wave soldering is a procedure in which PCB’s are fed to the

wave soldering machine from the opening on one side and the soldering is done by machine

and after the soldering is done PCB’s are collected from the another opening of the machine

and after that the pcb’s are cleaned in cleaning machine and then the PCB’s are than send to

testing department for testing according to the product Test procedure issued by the D&E

department. After testing PCB’s are lacquered and Send to the planning store for storage.

In electronic assembly, the cable assemblies, cable forms modules, drawers, racks and

shelters are assembled. Every shelter (e.g. - DMT) is made of racks, racks are made up of

drawers, drawers are made up of modules and modules are made up of PCB’s, cable

assembly and cable forms.

Every module or drawer before using in next assembly is send for testing according to their

PTP. Shop planning collects the purchase from the IG store, takes fabricated parts, PCB’s

etc. from planning stores and issued to the assembly department as per the part list of the

assembly to be made.

The documents issued to the assembly are:

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KS : Key Sheet

PL : Parts List

CL : Connection List for cable form

WL : Wiring List for modules

WD : Wiring Diagram

GA : General Assembly diagram

This department has been broadly classified as:

1. WORK ASSEMBLY RADAR e.g. : INDRA-2 , REPORTER ,

2. WORK ASSEMBLY NCS e.g. : EMC CA , MSSR , MFC

EMCCA: EQUIPMENT MODULAR FOR COMMAND CONTROL APPLICATION

MSSR: MONOPULSE SECONDARY SURVEILLANCE RADAR

MFC: MULTI FUNCTIONAL CONSOLE

The stepwise process followed by work assembly department is:

1) Preparation of part list that is to be assembled.

2) Preparation of general assembly.

3) Schematic diagram to depict all connection to be made and brief idea about all

components.

4) Writing list of all components.

METHOD OF PCB PROCESSING

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1. Tinning

2. Preparation

3. Mounting

4. Wave soldering

5. Touch up

6. Quality control

7. Ageing

8. Testing

9. lacquering (AV)

10. Storing

RADAR ASSEMBLY

This deals with the assembly of RADARS, e.g. INDRA-I, INDRA-II, FLY CATCHER,

EMMCA, IRMA, REPORTER etc.

The main projects under construction are:

Digital mobile tropo (DMT)

GHz radio relay

Digital encrypter

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QUALITY CONTROL WORKS

According to some laid down standards, the quality control department ensures the quality of

the product.

The raw materials and components etc. purchased are inspected according to the

specifications by the IG department. Similarly QC works department inspects all the items

manufactured in the factory.

The fabrication inspection checks all the fabricated parts and ensures that these are made as

per the part drawing. Plating, Painting and stenciling etc are done and checked as per the

BEL standards.

The assembly inspection department inspects all the assembled parts such as PCB, cable

assembly, cable form, modules, racks and shelters as per latest documents and BEL

standards.

The mistakes in the PCB can be categorized as:

D&E mistake

Shop mistake

Inspection mistake

A process card is attached to each PCB under inspection. Any error in the PCB is entered

into the process card by certain codes specified for each error or defect.

After mistake is detected, following actions are taken:

Observation is made.

Object code is given.

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Change code is prepared.

Recommended action is taken.

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DEPARTMENTALDEPARTMENTAL

WORKWORK

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PROJECT REPORT ON

AUTOMATED TEST EQUIPMENT (TESTING ON S790)

INTRODUCTION

Automated test equipment (ATE) is computer controlled test and measurement equipment,

arranged in such a way as to be able to test a unit with minimal human interaction. The

advantage of this kind of test is that they are repeatable and cost efficient in high volume.

The chief disadvantages are the upfront costs; programming and setup.

Automated test equipment can test components, printed circuit boards, and interconnections

and verifications. Test types for components include logic, memory, linear or mixed signal,

passive components and active components. Logic test systems are designed for handling the

testing of microprocessors, gate arrays, ASICs and other logic devices. Memory testers are

automated test equipment for the testing of SDRAM, DDR-SDRAM SIMMs and DIMMs.

Linear or mixed signal equipment is used for the testing of components such as analog-to-

digital converters (ADCs), digital-to-analog converters (DACs), comparators, track-and-hold

amplifiers and video products. These components incorporate features such as, audio

interfaces, signal processing functions and high-speed transceivers. Passive component

ATEs test passive components including capacitors, resistors, inductors etc. Typically testing

is done by the application of a test current. Discrete automated test equipment tests active

components including transistors, diodes, MOSFETs, Regulators, Triacs, Zeners, SCRs, and

JFETs.

Printed circuit board testers include manufacturing defect analyzers, in-circuit testers, and

functional analyzers. Manufacturing defect analyzers (MDAs) detect manufacturing defects,

such as shorts and missing components, but they can't test digital ICs as they test with the

UUT (unit under test) powered down (cold). As a result, they assume the ICs are good.

MDAs are also referred to as analog circuit testers. In-circuit analyzers test components that

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are part of a board assembly. The components under test are "in a circuit." The UUT is

powered up (hot). They are also referred to as digital circuit testers. A functional test

simulates an operating environment and tests a board against its functional specification.

They may also be referred to as emulators.

Test types for interconnection and verification include cable and harness testers and bare-

board testers. Cable and harness testers are used to detect opens (missing connections),

shorts (open connections) and miswires (wrong pins) on cable harnesses, distribution panels,

wiring looms, flexible circuits and membrane switch panels with commonly used connector

configurations. Other tests performed by automated test equipment include resistance and

hipot tests. Bare board automated test equipment is used to detect the completeness of a PCB

circuit before assembly and wave solder.

COMPONENTS OF ATE

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The Semiconductor ATE architecture consists of master controller (usually a computer) that

synchronizes one or more source and capture instruments (listed below). Historically,

custom-designed controllers or relays were used by ATE systems. The Unit Under Test

(UUT) is physically connected to the ATE by another robotic machine called a Handler or

Prober and through a customized Interface Test Adapter (ITA) or "fixture" that adapts the

ATE's resources to the UUT.

Most modern semiconductor ATEs include multiple Digital Signal Processing (DSP)

instruments used to measure a wide range of parameters, including: Digital Power Supply

(DPS), Parametric Measurement Units (PMU), Arbitrary Waveform Generators (AWG),

Digitizers, Digital IOs, and utility supplies. Each of these instruments perform different

measurements on the UUT. All of these instruments must be synchronized so the source and

capture waveforms very precisely aligned — a basic requirement in DSP-based ATE. The

DSP-based signal generation would require a number of sample patterns to be calculated and

be sent at very specific times.

There is a variety of different approaches that can be used for automatic test equipment. Each

type has its own advantages and disadvantages, and can be used to great effect in certain

circumstances. When choosing ATE systems it is necessary to understand the different types

of systems and to be able to apply them correctly.

TYPES OF ATE AUTOMATIC TEST SYSTEMS of 91

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There is a good variety of types of ATE systems that can be used. As they approach

electronics test in slightly different ways they are normally suited to different stages in the

production test cycle. The most widely used forms of ATE, automatic test equipment used

today are listed below:

Automatic optical inspection, AOI: AOI, Automatic Optical Inspection is widely

used in many manufacturing environments. It is essentially a form of inspection, but

achieved automatically. This provides a much greater degree of repeatability and

speed when compared to manual inspection. AOI, automatic optical inspection it is

particularly useful when situated at the end of a line producing soldered boards. Here

it can quickly locate production problems including solder defects as well as whether

the correct components and fitted and also whether their orientation is correct. As

AOI systems are generally located immediately after the PCB solder process, any

solder process problems can be resolved quickly and before too many printed circuit

boards are affected.

AOI automatic optical inspection takes time to set up and for the test equipment to

learn the board. Once set it can process boards very quickly and easily. It is ideal for

high volume production. Although the level of manual intervention is low, it takes

time to set up correctly, and there is a significant investment in the test system itself.

Automated X-Ray inspection, AXI: Automated X-Ray inspection has many

similarities to AOI. However with the advent of BGA packages it was necessary to be

able to use a form of inspection that could view items not visible optically.

Automated X-Ray inspection, AXI systems can look through IC packages and

examine the solder joints underneath the package to evaluate the solder joints.

ICT In circuit test: In-Circuit Test, ICT is a form of ATE that has been in use for

many years and is a particularly effective form of printed circuit board test. This test

technique not only looks at short circuits, open circuits, component values, but it also

checks the operation of ICs. Although In Circuit Test, ICT is a very powerful tool, it

is limited these days by lack of access to boards as a result of the high density of

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tracks and components in most designs. Pins for contact with the nodes have to be

very accurately placed in view of the very fine pitches and may not always make

good contact. In view of this and the increasing number of nodes being found on

many boards today it is being used less than in previous years, although it is still

widely used.

Manufacturing Defect Analyzer, MDA: A Manufacturing Defect Analyzer, MDA

is another form of printed circuit board test and it is effectively a simplified form of

ICT. However this form of printed circuit board test only tests for manufacturing

defects looking at short circuits, open circuits and looks at some component values.

As a result, the cost of these test systems is much lower than that of a full ICT, but the

fault coverage is less.

Functional testing, including rack and stack: Functional test can be considered as

any form of electronics testing that exercises the function of a circuit. There are a

number of different approaches that can be adopted dependent upon the type of

circuit (RF, digital, analogue, etc), the degree of testing required. The main

approaches are outlined below:

1. Functional Automatic Test Equipment, FATE: This term usually refers to

the large functional automatic test equipment in a specially designed console.

These automatic test equipment systems are generally used for testing digital

boards but these days these large testers are not widely used. The increasing

speeds at which many boards run these days cannot be accommodated on

these testers where leads between the board under test and the tester

measurement or stimulus point can result in large capacitances that slow the

rate of operation down. In addition to this fixtures are expensive as is the

program development. Despite these drawbacks these testers may still be used

in areas where production volumes are high and speeds not particularly high.

They are generally used for testing digital boards.

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2. Rack and stack test equipment using GPIB: One way in which boards, or

units themselves can be tested is using a stack of remotely controlled test

equipment. The most widely method of controlling the test equipment is still

to use the General Purpose Interface Bus (GPIB). There may also be a test

interface adapter required to control and interface to the item under test.

Whilst the GPIB is relatively slow and has been in existence for over 30 years

it is still widely used as it provides a very flexible method of test. Laboratory

test equipment can often be used as most items of lab test equipment have a

GPIB port. The main drawback of GPIB is its speed and the cost of writing

the programmes although packages like LabView can be used to aid program

generation and execution in the test environment. Fixtures or test interfaces

can also be expensive.

3. Chassis or rack based test equipment: One of the major drawbacks of the

GPIB rack and stack automatic test equipment approach is that it occupies a

large amount of space, and the operating speed is limited by the speed of the

GPIB. To overcome these problems a variety of standards for systems

contained within a chassis have been developed.

The idea of containing test instruments within a chassis was first developed

under the VXI (VME eXtensions for Instrumentation) guise. The system uses

test instruments on a card that can be slotted into a standard chassis. This

saves both space and cost when compared to the stand-alone instruments as

well as proving an increase in communications speed when compared to other

technologies such as GPIB. Later introductions of PXI and then PXI Express

provided for lower cost instrumentation while still retaining the advantages of

the chassis approach.

Although there are a variety of ATE, automatic test equipment approaches that can be used,

these are some of the more popular systems in use. They can all use test management

software such as LabView to assist in the running of the individual tests. This enables

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facilities such as the ordering of tests, results collection and printout as well as results

logging, etc.

JTAG Boundary scan testing: Boundary scan is a form of testing that has come to

the fore in recent years. Also known as JTAG, Joint Test Action Group, or by its

standard IEEE 1149.1, boundary scan offers significant advantages over more

traditional forms of testing and as such has become one of the major tools in

automatic testing.

As a result of its ability to test boards and even ICs with very limited physical test

access, Boundary Scan / JTAG has become very widely used.

With the requirement for testing circuit efficiently increasing while test access is

decreasing, efficient methods of testing are needed. Boundary scan uses special

boundary scan ICs that have a shift register in the output. By connecting boundary

scan compatible ICs serially on a board (or just using the boundary scan chain in an

IC for individual IC testing) and enabling the boundary scan chain, it is possible to

send in a serial data word, and then monitor the exiting data word. Analysing the exit

data train enables the test information to be accessed. In this way it is possible to gain

a high level of test access without compromising the circuit.

Combinational test: No single method of testing is able to provide a complete

solution these days. To help overcome this various ATE automatic test equipment

systems incorporate a variety of test approaches. These combinational testers are

generally used for printed circuit board testing. By doing this, a single electronics test

is able to gain a much greater level of access for the printed circuit board test, and the

test coverage is much higher. Additionally a combinational tester is able to undertake

a variety of different types of test without the need to mover the board from one tester

to another. In this way a single suite of tests may include In-circuit testing as well as

some functional tests and then some JTAG boundary scan testing.

By utilizing all the different test techniques appropriately, it is possible to ATE automatic test

equipment to be used to its fullest advantage. This will enable tests to be executed swiftly,

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while still providing a high level of coverage. Inspection techniques including AOI and X-ray

inspection can be used along with In-circuit test, and JTAG boundary scan testing.

Functional testing can also be used. While it is possible to use different types of test, it is

necessary to ensure that products are not over tested as this wastes time. For example if AOI

or X-Ray inspection is used, it may not be appropriate to use In-circuit testing. The place of

JTAG boundary scan testing should also be considered. In this way the most effective test

strategy can be defined.

TEST EQUIPMENT SWITCHING

The addition of a high-speed switching system to a test system’s configuration allows for

faster, more cost-effective testing of multiple devices, and is designed to reduce both test

errors and costs. Designing a test system’s switching configuration requires an understanding

of the signals to be switched and the tests to be performed, as well as the switching hardware

form factors available.

AUTOMATED OPTICAL INSPECTION

Automatic or automated optical inspection, AOI, is a key technique used in the manufacture

and test of electronics printed circuit boards, PCBs. Automatic optical inspection, AOI

enables fast and accurate inspection of electronics assemblies and in particular PCBs to

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ensure that the quality of product leaving the production line is high and the items are built

correctly and without manufacturing faults.

Need for AOI, automatic optical inspection

Despite the major improvements that have been made, modern circuits are far more

complicated than boards were even a few years ago. The introduction of surface mount

technology and the subsequent further reductions in size mean that boards are particularly

compact. Even relatively average boards have thousands of soldered joints, and these are

where the majority of problems are found.

This increase in the complexity of boards also means that manual inspection is not a viable

option these days. Even when it was an accepted approach, it was realized that it was not

particularly effective as inspectors soon tired and poor and incorrect construction was easily

missed. With the marketplace now requiring high volume, high quality products to be

brought to market very quickly very reliable and fast methods are needed to ensure that

product quality remains high. AOI, automatic optical inspection is an essential tool in an

integrated electronics test strategy that ensure costs are kept as low as possible by detecting

faults early in the production line.

One of the solutions to this is to use automated or automatic optical inspection systems.

Automated optical inspection systems can be placed into the production line just after the

solder process. In this way they can be used to catch problems early in the production

process. This has a number of advantages. With faults costing more to fix the further along

the production process they are found, this is obviously the optimum place to find faults.

Additionally process problems in the solder and assembly area can be seen early in the

production process and information used to feedback quickly to earlier stages. In this way a

rapid response can ensure that problems are recognised quickly and rectified before too many

boards are built with the same problem.

AOI, automatic optical inspection basics

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AOI, automatic optical inspection systems use visual methods to monitor printed circuit

boards for defects. They are able to detect a variety of surface feature defects such as

nodules, scratches and stains as well as the more familiar dimensional defects such as open

circuits, shorts and thinning of the solder. They can also detect incorrect components,

missing components and incorrectly placed components. As such they are able to perform all

the visual checks performed previously by manual operators, and far more swiftly and

accurately.

They achieve this by visually scanning the surface of the board. The board is light by several

light sources and one or more high definition cameras are used. In this way the AOI machine

is able to build up a picture of the board

The automated optical inspection, AOI system uses the captured image which is processed

and then compared with the knowledge the machine has of what the board should look like.

Using this comparison the AOI system is able to detect and highlight any defects or suspect

areas.

AOI uses a number of techniques to provide the analysis of whether a board is satisfactory or

has any defects:

Template matching: Using this form of process the AOI, automated optical

inspection system compares the image obtained with the image from a "golden

board".

Pattern matching: Using this techniques the AOI system stores information of both

good and bad PCB assemblies, matching the obtained image to these.

Statistical pattern matching: This approach is very similar tot hat above, except

that it uses a statistically based method of addressing problems. By storing the results

of several boards and several types of failure, it is able to accommodate minor

acceptable deviations without flagging errors.

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In order to build up the database of what the board should be, both known status boards and

PCB design information is used as described later.

As technology has improved it has been able for AOI systems to very accurately predict

defects and have a small number of no defect found scenarios. As such AOI systems form a

very useful element in a sophisticated manufacturing environment.

AOI image capture and analysis

One of the key elements of an AOI, automated optical inspection system is the image capture

system. This captures an image of the printed circuit board, PCB assembly which is then

analysed by the processing software within the AOI system. There are many variants of

image capture system dependent upon the exact application and the complexity / cost of the

AOI system.

Imaging systems may comprise a single camera or there may be more than one to provide

better imaging and the possibility of a 3D capability. The cameras should also be able to

move under software control. This will enable them to move to the optimum position for a

given PCB assembly.

In addition to this the type of camera has an impact on performance. Speed against accuracy

is a balance that has to be struck and will impact on the camera type used:

Streaming video: One type of camera used for automated optical inspection, AOI,

takes streaming video from which complete frames are taken. The captured frame

then enables a still image to be generated on which the signal processing is

performed. This approach is not as accurate as other still image systems but has the

advantage of very high speed.

Still image camera system: This is generally placed relatively close to the target

PCB and as a result it requires a good lighting system. It may also be necessary to be

able to move the camera under software control.

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When analyzing an image of a board, the AOI system looks for a variety of specific features:

component placement, component size, board fiducials, label patterns (e.g. bar codes),

background color and reflectivity, etc. As an important element of its task the AOI system

also inspects the soldered joints to ensure they indicate that the joints are satisfactory.

When analyzing the boards the AOI system must take into account many variations between

good boards. Not only do components vary considerably in size between batches, but also the

color and reflectivity. Often there are also differences in the silk screening where ink

thickness and color typeface may change slightly.

AOI light source

Lighting is a key element in the AOI system. By choosing the correct lighting source it is

possible to highlight different types of defect more easily. With the advances that have been

made in lighting technology in recent years, this has enabled lighting to be used to enhance

the images available and in turn this enables defects to be highlighted more easily with a

resultant reduction in processing required and an increase in speed and accuracy.

Most AOI systems have a defined lighting set. This will depend upon the operation required

and the product types to be tested. These have usually been optimized for the anticipated

conditions. However sometimes some customization may be required, and an understanding

of lighting is always of use.

A variety of types of lighting are available:

Fluorescent lighting: Fluorescent lighting is widely used for AOI, automated

optical inspection applications as it provides an effective form of lighting for viewing

defects on PCBs. The main problem with fluorescent lighting for AOI applications is

that the lamps degrade with time. This means that the automated optical inspection

system will be subject to a constantly changing levels and quality of light

LED lighting: The development of LED lighting has meant that AOI, automated

optical inspection systems are able to adopt a far more stable form of lighting.

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Although LED lighting does suffer from a reduction in light output from the LEDs

over time, this can be compensated for by increasing the current. Using LED lighting,

the level of lighting can also be controlled. LEDs are therefore a far more satisfactory

form of lighting than fluorescent or incandescent lights that were used years ago

Infra-red or ultra-violet: On some occasions infra-red or ultra-violet lighting may

be required to enhance certain defects, or to enable automated optical inspection to be

carried out to reveal certain types of defect.

Apart from the form of lighting, the positioning of the lighting for an automatic optical

inspection system, AOI, is equally important. The light sources require positioning to not

only to ensure that all areas are well light, which is particularly important when certain

components may cast shadows, but also to highlight defects. Careful adjustment may be

needed for different assemblies.

AOI, automated optical inspection system programming

In order to be able to test a PCB assembly using AOI, automatic optical inspection, the

details for an acceptable board must be stored within the system. This programming activity

must be carried out correctly if the AOI system is to be able to correctly detect any defects on

the PCB assemblies passing through.

There are several methods that can be used to program an AOI system:

Use of "Golden Board": One method is to provide a known good board as a target

for the AOI, automated optical inspection system to use. This is passed through the

system so that it can learn the relevant attributes. It will look at the components, the

solder profiles of each joint, and many other aspects. In order to provide the system

with enough variance data several boards are often required.

Algorithm based programming: PCB data is provided to the system and it then

generates its own profile for the board. This scheme will also require real boards, but

fewer are generally required.

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There are advantages and disadvantages to both systems. It is a balance between set-up time,

maintenance, accuracy and the requirements for the particular AOI, automated optical

inspection system. Typically the requirements will be largely dependent upon the machine in

use.

It is essential that any printed circuit board manufacturing area is able to check the quality of

the boards coming off the end of the line. Only in this way are they able to monitor quality

and when problems are detected to rectify the process so that further boards are not affected

by the same problems. In this way automatic optical inspection and where necessary X-ray

inspection are two essential tools for the manufacturing industry.

X-RAY INSPECTION

Automatic optical inspection works very well in electronics manufacturing for printed circuit

boards where joints are visible. However many PCBs today are using technologies such as

ball grid array, BGA integrated circuits and chip scale packages, CSPs where the solder

connections are not visible. This has arisen as a result of the need for greater numbers of

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interconnections to integrated circuit packages and as a general result of increasing

complexity. In these and many other instances it is necessary to carry out checks using

automated X-Ray inspection, AXI, equipment that can not only check the solder joints under

components, but also reveal many defects in solder joints that may not be visible with

ordinary optical inspection equipment.

In recent years, the need for automated X-Ray inspection equipment has grown considerably

and as a result, a much wider range of equipment is available. Additionally the techniques

used in automated X-Ray inspection equipment has improved and this has enabled far greater

levels of detection to be achieved for printed circuit board, PCB manufacture.

As one significant improvement in AXI, automated X-ray inspection, not only are 2D or two

dimensional techniques available, but machines utilizing 3D technology are available and

give significant improvements in performance.

AXI technology features

AXI, automated X-ray inspection systems are able to monitor a variety of aspects of a printed

circuit board assembly production. They would normally be placed after the solder process to

monitor defects in PCBs after leaving the soldering process. They have the distinct advantage

over optical systems that they are able to "see" solder joints that are under packages such as

BGAs, CSPs and flip chips where the solder joints are hidden.

AXI, automated X-ray inspection systems are not only able to "see" through the chips, but

they are also able to provide an internal view of the solder joints. In this way they are able to

detect voiding within a solder joint that may otherwise look perfectly acceptable.

This means that AXI, automated X-ray inspection systems are able to provide additional

information over that which could be provided by purely optical systems to ensure that solder

joints are being made to the required standard.

AXI, automated optical inspection can inspect the features of solder joints providing

information on the way the soldering process is operating. Parameters such as solder

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thickness, joint sizes and profiles can be undertaken on specific joints on boards. These can

then be used to provide data on the solder process and how well it is operating. AXI systems

are also able to see the heel of the joint which AOI systems are unable to see as they are

masked by the leads from the ICs as shown.

Solder joint geometry for a typical Quad Flat Pack IC

When an automated X-ray inspection system, or an optical system is used within an

electronics PCB manufacturing process, the defects and other information detected by the

inspection system can be quickly analyzed and the process altered to reduce the defects and

improve the quality of the process. In this way not only are actual faults detected, but the

process can be altered to reduce the fault levels on the boards coming through. Accordingly

they ensure that the highest standards are maintained and they are particularly useful when

new boards are being set up and the process needs to be optimized.

It should be realized that AXI is only one of the number of tools that can be used within an

electronics PCB manufacturing organization. Two other tools, namely AOI, automatic

optical inspection, and ICT, in-circuit test can provide similar information in many areas. The

table below provides a comparison of the different types on information that each form of

automatic test equipment, ATE can provide.

Automated X-ray inspection, AXI has an important place in many electronics PCB

manufacturing organizations. AXI is able to provide a fast and in-depth and accurate

inspection of PCBs passing through the production facility and in this way provide real-time

feedback that enables the production system to be optimized to enable high quality reliable

circuits to be produced. Although more expensive than some other forms of inspection, AXI

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has many advantages and these need to be carefully balanced against the costs to ensure

whatever choice is made, it is correct for the particular production environment.

IN-CIRCUIT TESTING, ICT

In-Circuit Test, ICT is a powerful tool for printed circuit board test. Using a bed of nails in-

circuit test equipment it is possible gain access to the circuit nodes on a board and measure

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the performance of the components regardless of the other components connected to them.

Parameters such as resistance, capacitance and so forth are all measured along with the

operation of analogue components such as operational amplifiers. Some functionality of

digital circuits can also be measured, although their complexity usually makes a full check

uneconomic. In this way, using ICT, In-Circuit Test, it is possible to undertake a very

comprehensive form of printed circuit board test, ensuring that the circuit has been

manufactured correctly and has a very high chance of performing to its specification.

Basic concept of ICT, in-circuit test

In circuit test equipment provides a useful and efficient form of printed circuit board test by

measuring each component in turn to check that it is in place and of the correct value. As

most faults on a board arise out of the manufacturing process and usually consist of short

circuits, open circuits or wrong components, this form of testing catches most of the

problems on a board. Even when ICs fail, one of the major reasons is static damage, and this

normally manifests itself in the areas of the IC close to the connections to the outside world,

and these failures can be detected relatively easily using in-circuit test techniques. Naturally

an in-circuit test does not give a test of the functionality of a board, but if it has been

designed correctly, and then assembled correctly, it should work.

In-circuit test equipment consists of two main parts. The first is the tester itself. This consists

of a matrix of drivers and sensors that are used to set up and perform the measurements.

There may be 1000 or more of these driver sensor points. These are normally taken to a large

connector conveniently located on the system.

This connector interfaces with the second part of the tester - the fixture. In view of the variety

of boards this will be designed specifically for a particular board, and acts as an interface

between the board and the in circuit tester. It takes the connections for the driver sensor

points and routes them directly to the relevant points on the board using a "bed of nails".

Bed of nails tester

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A bed of nails tester is a traditional electronic test fixture which has numerous pins inserted

into holes in an Epoxy phenolic glass cloth laminated sheet (G-10) which are aligned using

tooling pins to make contact with test points on a printed circuit board and are also connected

to a measuring unit by wires. Named by analogy with a real-world bed of nails, these devices

contain an array of small, spring-loaded pogo pins; each pogo pin makes contact with one

node in the circuitry of the UUT (Unit Under Test). By pressing the UUT down against the

bed of nails, reliable contact can be quickly, simultaneously made with hundreds or even

thousands of individual test points within the circuitry of the UUT. The hold-down force may

be provided manually or by means of a vacuum pulling the UUT downwards onto the nails.

Devices that have been tested on a bed of nails tester may show evidence of this after the

fact: small dimples (from the sharp tips of the pogo pins) can often be seen on many of the

soldered connections of the PCB.

Typically, four to six weeks are needed for the manufacture and programming of such a

fixture. Fixture can either be vacuum or press-down. Vacuum fixtures give better signal

reading versus the press-down type. On the other hand, vacuum fixtures are expensive

because of their high manufacturing complexity. The bed of nails or fixture as generally

termed is used together with a in-circuit tester such as MTS 300 from Digital test (Germany),

i3070, 3070 from Agilent (USA), Teradyne Spectrum Series and continuation of the former

Genrad Test station series under the Teradyne flag (USA), SPEA (Italy) 3030 series, IFR

4200 series, was Marconi Test prior to acquisition by IFR (USA), TRI (Taiwan), Okano

(Japan), SEICA, HIOKI(Japan) and Checksum (USA).

Driver-sensors for ICT

Driver-sensors are the active circuits that are used for making the measurements. Normally

drivers and sensors are always present in pairs in an in-circuit test system. As the name

suggests the drivers supply a voltage or current to enable a node in the circuit to be driven to

a particular state. They normally have a reasonably high capability to enable the node to be

driven to the required state despite the condition of the surrounding circuitry. Typically they

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PROJECT REPORT

may need to force the output of a digital IC to a given state despite the natural output state of

the device. To achieve this, the output impedance of the driver must be very low.

Sensors are used to make the measurements. Like most other measuring devices these need

to have a high impedance so that they do not disturb the circuit being measured.

Guarding

The key to the success of in-circuit testing is a technique known as guarding. It is very easy

to measure the value of a component when it is not in a circuit. For example a resistor value

can be measured by simply placing an ohmmeter across it. However when the component is

in a circuit, the situation is somewhat different. Here it is most likely that there are other

paths around the component that will alter the value that is measured.

To overcome this problem and gain a far more accurate indication of the value of the

component a technique known as guarding is used. Here the nodes around the component

under test are earthed and in this way any leakage paths are removed and more accurate

measurements made.

ICT programme generation

One of the advantages of the in-circuit tester is that programme generation can be made

much simpler than that of a functional tester. It is possible for much of the programme to be

generated automatically from knowledge of the circuit. This can be provided very easily from

the printed circuit files. The information about the nodes along with the circuit value

information can be combined to give a programme that can then be altered manually to

provide

Multiplexing

Today's printed circuit boards can be very complicated. On larger boards the node count can

easily rise over a thousand and may reach several thousand on some. To have dedicated pins

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on the tester for each node can be very costly as each one requires its own driver sensor. To

reduce this manufacturers introduce a system known as multiplexing. Here a particular node

may be placed through a switching matrix so that it can address more than one node. The

number of nodes that are addressed by each tester primary node is known as the multiplex

ratio.

Whilst it may appear to be an excellent idea to reduce costs, it reduces the flexibility of the

tester. Only one of the multiplexed nodes can be accessed at any time. This can cause

restrictions in the programming and also in the fixture itself. Considerable thought has to be

given to the fixture construction to ensure that two pins on the same multiplex are not

required at the same time. It may also cause problems if the pins are allocated automatically

by software that generates the test programme and fixture wiring diagram.

When buying a machine it is worth checking whether multiplexing is used and what the ratio

is. With this information a judgment can be made of the cost saving against the reduction in

flexibility.

Fault coverage

With access to all the nodes on the board, manufacturers generally quote that it is possible to

find around 98% of faults using in circuit test. This is very much an ideal figure because

there are always practical reasons why this may not be achieved. One of the major reasons

that it is not always possible to gain complete coverage of the board is Low value capacitors

are a particular problem as the spurious capacitance of the test system itself means that low

values of capacitance cannot be measured accurately if at all. A similar problem exists for

inductors but at least it is possible if a component is in place by the fact that it exhibits a low

resistance.

Further problems are caused when it is not possible to gain access to all the nodes on the

board. This may result from the fact that the tester has insufficient capacity, or it may result

from the fact that a point to which the tester needs access is shielded by a large component,

or anyone of a number of reasons. When this occurs it is often possible to gain a level of

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confidence that the circuit has been correctly assembled by what may be termed "implied

testing" where a larger section of circuit containing several components is tested as an entity.

However the confidence will be less and location of faults may be more difficult.

Pros and Cons of ICT

One advantage of an ICT as a first line form of printed circuit board test is that most board

faults arise from problems in manufacture. These might arise from the incorrect component

inserted, a wrong value resistor, a diode in the wrong way. These are very easily and quickly

located using ICT.

An In-Circuit tester is also very easy to program and no long diagnostic routines are required

to locate any problems. While the fixtures can be reasonably expensive the production of

these as well can be automated to a large degree. However against this any changes to the

board layout as a result of up-issuing the board can result in changes to the fixture that may

be difficult to implement.

Another advantage of ICT as a form of printed circuit board test is that the test results are

easily interpreted. This enables them to be used by a variety of people. As a result their

running costs are less than some other systems that might need highly skilled diagnostic

technicians and as a result this makes them attractive for use on the shop floor to locate most

of the problems.

There are some other limitations. The first is that they obviously cannot provide a full

functional check of the specification of the board. During the ICT printed circuit board test,

the board is not being exercised in its operational mode, its operational parameters cannot be

checked.

Another problem that is becoming more difficult to overcome is that access to the nodes is

becoming more difficult. Many years ago it was possible to place special pads onto the

boards to enable the fixture pins to connect to the board easily. Now boards are so compact

that there is no possibility of being able to apply special pads to each node. Also the size of

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component connections is becoming much smaller and this means that probing these points is

far more difficult. However it is still possible to achieve a good coverage on many boards.

One problem that concerned people, especially some years ago was that of back driving.

When performing a test some nodes have to be held at a certain level. This meant forcing the

output of possibly a digital integrated circuit to an alternative state purely by applying a

voltage to over-ride the output level. This naturally put a strain on the output circuitry of the

chip. It is generally assumed that this can be done for a very short period of time - sufficient

to undertake the test - without any long-term damage to the chip. However with the

geometries in ICs shrinking, this is likely to become more problematical.

Roving probe

To reduce the fixture costs, provide additional flexibility and enable board changes to be

accommodated by updates to a software programme, a type of in circuit tester known as a

roving probe or roving prober may be used. Instead of having a bed of nails fixture a simple

fixture to hold the board is used and probes that move under software control are used to

probe the relevant points on the board. These systems normally have a number of probes,

some that can access both sides of the board.

These systems provide a slower form of printed circuit board test than the systems that use a

bed of nails fixture because there is a delay between measurements as the probe moves to the

next position and this will naturally reduce the throughput. However the system is cheaper

for the maintenance and introduction of new boards because of the reduced fixturing costs

and reduced cost of changes.

In circuit test has many advantages and is an ideal form of printed circuit board test in many

respects. However as a result of the rapidly shrinking component sizes and the resultant

difficulties in gaining access to all the nodes on boards testing using ICT has been steadily

becoming more difficult. Accordingly many people have been predicting the imminent

demise of ICT as a form of printed circuit board test. It remains to be seen how long this will

take.

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S790

The S790 is a combinational test system which is very modular and capable of handling a

number of test requirements. This means that the digital and analog pin cards, power

supplies, analog instruments, fixtures, test programs, etc. are all capable of being configured

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S790 VXI SYSTEM

The architecture of this system is based around a VXI rack and the National Instruments

CPU30 slot zero controller. A CATE workstation connects to the tester via an Ethernet link.

By using the CPU30 card VXI instrumentation can be easily introduced and controlled by the

system. The instrumentation can also be synchronized and pipelined to facilitate faster

programming.

IEEE instrumentation can also be controlled and interfaced to the system using the CPU30

card. The heart of the 790-VXI or 760 VXI capability is the National Instruments VXIcpu-30

card. This card is the embedded processor which runs the VXworks operating system.

The terminology is overviewed below:

• VME - this is a 'standard' for backplane communications for small computer boards. It is a

multi master bus on which any device with bus master capability can arbitrate for control of

the data transfers. There is no central bus controller unlike the IEEE system.

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• VXI - this is the VME bus eXtension for Instrumentation. It is a standard based on the

VME bus maintaining the modular approach but extending it for instrumentation.

• VXworks - the operating system for the VXIcpu-30 card.

• MXI - Multi system Extension Interface. This is an ultra high speed communication link

between devices and operates at speeds up to 20 MBytes per second. It is based on the VME

and NUBus and is a general purpose interface bus.

• VXI instruments - single card instruments fitting into a VXI crate. They do not have a

front panel but can be used alongside, or instead of, IEEE instruments. The VXI specification

defines protocols for data transfer, clear, trigger, local lockout, SRQ and serial poll facilities.

The VXI logical address is equivalent to the GPIB address.

VXI TECHNOLOGY

VXI Technology is used to control the programmable instruments fitted to the s790 VXI test

system. VXIbus is an abbreviation of “VME extension for Instruments bus” which is based

upon industry-standard VMEbus computer architecture extends modular systems approach to

instruments. The goal of the VXIbus is to define technically a modular instrument standard

open to all manufacturers and be compatible with present industry standards.

The VXIbus specification details technical requirements for compatibility of:

• main-frames

• backplanes

• power supplies

• instrument modules

for interconnecting and operating different manufacturer's products within the same card

chassis if they comply with the VXIbus specification.

VXI can be thought of as bringing the “UNIX and ETHERNET type standard” to testing in

the future.

Advantages of VXIbus:

VXIbus specification allows modular ATE to be developed, detailing both mechanical and

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Longer system support -- through wider choice of product and inter-operability of

manufacturer's devices. Standard VMEbus cards will operate within the VXIbus system.

Accommodates different system hierarchy -- the user is not locked to one type of processor,

operating system software or interface to host computer. As long as a system can 'drive' the

protocol a user should be able to swap the VXIbus hardware from system to system.

Shared system resources -- VXIbus uses a common backplane chassis between instruments,

which also provides power supplies and cooling. Since the instrument manufacturer does not

need to include these on the board(s), less components are required which should result in

lowering of costs.

Higher level of performance -- VXI instruments have significant improvements over more

traditional instrument control by being able to pass commands and data between controller /

instruments at higher speeds, also higher degree of accuracy / synchronisation when one

module needs to start / stop operations on another.

FUNCTIONAL TESTING

Functional Digital Testing

Functional Test Programs are used to test whole circuit boards, modules or clusters which

may be made up of digital or analog circuitry. Functional programs can be either Go/Nogo or

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Diagnostic and are often classified as Digital, Analog or Hybrid although of course in the

CATE environment the different types of tests may be mixed to suite your requirements.

Generation process for Digital Test Programs

The information is divided into the following sections:

Predictive Digital Go/Nogo Test Programs

Learned Digital Go/Nogo Test Programs

Digital Diagnostic Test Programs

Predictive Digital Go/Nogo Test Programs

Predictive programs are made up of tests that use Digital Test Channels(DTC) to drive and

sense logic levels at the inputs and outputs of the Unit Under Test. The input and the output

logic states for each test pattern (vector) are defined by the programmer. If you have no

Board Description, the test patterns must be entered as source code in Mediator files. If you

have a test database that contains a compiled Board Description and Wire List, the test

vectors can be placed in Digital Workbenches which will display the logic patterns

graphically.

Learned Digital Go/Nogo Test Programs

Learned Digital programs are made up of tests that use Digital Test Channels(DTC) to drive

and sense logic levels at the inputs and outputs of the Unit Under Test. The input states are

defined by the programmer. The output states are learned from a good unit by running the

test system in a “Learn Test Outputs” mode. If you have no Board Description, the test

patterns must be entered as source code in Mediator files. If you have a test database that

contains a compiled Board Description and Wire List, the test vectors can be placed in

Digital Workbenches which will display the logic patterns graphically.

Digital Diagnostic Test Programs

Digital diagnostic programs are made up of tests that use Digital Test Channels(DTC) to

drive and sense logic levels at the inputs and outputs of the Unit Under Test. The input states

are defined by the programmer. The output states are normally simulated but may be learned

from a good unit by running the test system in a “Learn Test Outputs” mode. The fault

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diagnosis process uses the system Fast Probe to check the logic activity of networks by back-

tracking along a fault path. To do this the Analyst software uses Good Activity trace data.

The trace data contains information about the logic levels on each network and for each test

vector in the program. Trace data may be simulated or learned from a good unit.

Functional Analog Testing

Functional Test Programs are used to test whole circuit boards, modules or clusters which

may be made up of digital or analog circuitry. Functional programs can be either Go/Nogo or

Diagnostic and are often classified as Digital, Analog or Hybrid.

Generation process for Analog Test Programs

The information is divided into the following sections:

Analog Go/Nogo Test Programs

Hybrid Diagnostic Programs

Manual Analog Diagnostic Programs

Analog Go/Nogo Test Programs

Analog test programs are made up of tests that contain instructions to connect instruments

and make measurements. The signal routing, instrument set-up, measurement and limits of

the test are defined by the programmer. Mediator variables are used to hold the results of a

measurement. The program code is usually placed in Instrument Workbenches. The Power

supply set-ups may be placed in a separate Mediator file in the test plan or in a generic event

of the workbench.

Hybrid Diagnostic Programs

Hybrid diagnostic programs can be a mixture of digital and analog tests. They make use of

the automatic probing facilities of the CATE software and because of this, we must have a

compiled Board Description in the test database in which we are going to create the Test

Plan.

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Manual Analog Diagnostic Programs

Manual analog diagnostic programs are made up of only analog tests. Because they do not

make use of the automatic probing facilities of the CATE software there is no requirement to

have a compiled Board Description in the test database. The fault detection process and

diagnostic information is written by the programmer.

ANALYST

To successfully diagnose faults on complex, often high speed, electronics, DiagnoSYS testers

have a number of software and hardware tools available which permit diagnosis usually to a

single failing device or manufacturing fault. These tools are controlled by a Diagnostic

System called ANALYST.

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Purpose of a Diagnostic System

Once a test program has identified that a UUT is faulty, it is normally necessary to identify

the source of the fault so that repairs may be carried out. On simple UUT's it may be possible

to identify the failure from the fault symptoms, or from diagnostic messages included by the

programmer. Many UUT's however, are too complex for this simple approach. ANALYST

interprets the information gained from running a test program against a faulty UUT and

compares it against previous failure, and stored good activity, information. From this

information ANALYST is able to identify the failure area with a high degree of accuracy.

ANALYST is designed to adapt to the nature of the UUT, and to the facilities available on

the tester. When the UUT fails, the test program produces a fault signature. Fault signatures

are inspected by ANALYST and compared against any Fault Dictionaries available (usually

obtained from digital simulation). If a matching fault signature is found, ANALYST can

produce a diagnosis from this information.

A fault dictionary cannot always provide sufficient information to diagnose to one specific

fault. In this case, or if no fault dictionary is available, ANALYST uses a guided probe to

backtrack a failure location.

ANALYST uses a series of information to aid its diagnostics:

Test Program: provides the stimulus and the output changes to a UUT via test channels.

The test channels monitor these changes (or in the case of a faulty condition, the lack of

changes) to determine the functionality of the UUT - i.e. PASS or FAIL.

UUT: Unit Under Test provides information to be compared with the information already

held on the test database from both the edge connector and the internal networks.

System Probe: is used to gather the information from the networks of the UUT for

comparison with the known good activity stored on the database and determines if it is

faulty or not.

Diagnostic Algorithm: guides the system probe to the networks which are on the fault

path (i.e. where the fault propagates to the edge connector to cause the UUT to fail and

stop the program).

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Network Activity: is a record of the activity for each network on the UUT. It is stored on

the database and compared with the data measured by the System Probe on a faulty UUT

network. Analyst compares the two sets of data and makes decisions on probing routes or

diagnostic messages.

Diagnostic Messages: are displayed by the system on the screen and/or ticket printer

during the diagnostic process.

Operator Messages: are displayed during the diagnostic process to guide the operator to

the fault on the UUT.

FAST-PROBE: is a hand held probe positioned by the operator according to probing

instructions supplied by ANALYST. FAST-PROBE can be used to collect high speed

digital

activity, signature analysis data and analogue activity information from the UUT, which

ANALYST compares with stored good information to track failures.

NAIL-PROBE: is similar to FAST-PROBE in operation, except that it uses existing

fixture nails to probe the UUT. ANALYST can gather information from NAIL-PROBE

automatically, thereby reducing or avoiding the need for operator probing and thus

speeding up the diagnosis time. Since it lacks the mobility of FAST-PROBE,

NAILPROBE cannot be used in the additional modes of FASTPROBE nor can it

diagnose open track faults.

USER PROBE: A special user probe can be supplied on suitably configured testers,

which may be used in conjunction with ANALYST.

CDP: Fault diagnostics can be much simplified, particularly on bus structured boards, if

ANALYST knows which devices are driving at a given point, and the direction in which

they are driving. ANALYST can use CDP information to concentrate on devices which

are active at the time of a failure, leading to a reduction in operator probing and faster

diagnostics.

FAULT DICTIONARIES: are used by ANALYST to produce the most comprehensive

fault diagnosis possible, and to minimize the amount of probing required to backtrack a

fault. The backtracking algorithm knows the logical dependency of the devices on the

UUT, from the compiled netlist information in the database. Using this information the

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algorithm performs a search of the UUT, following the earliest first fail. The algorithm

starts from a failing input pin of a device, probes the pin and selects a possible driver for

the pin. The inputs of this driver are then located and probed.

LOCATOR: is a software package which may be called by ANALYST to provide

topological information to an operator. A layout of part of the board is shown with a clear

identification of the setting up/probing points referred to in the display window.

Inconsistent Activity and Misprobe Check

• Operator Mis-probes

• UUT Trace Inconsistencies

• UUT Track Open Checks

ANALYST has a collection of tools which collectively detect operator misprobes, giving a

further reduction in the number of probe operations needed. The misprobe check does not

merely discover operator misprobes, it also detects inconsistent UUT activity and track-open

faults. “On the fly” misprobe checks perform multiple probes on the same networks in order

to check that the track is continuous and that the operator is probing correctly. The misprobe

check is therefore a collection of tools which ensure that the operator miss-probes, track-

opens and inconsistent UUT activity are still discovered and dealt with, while still only

performing one probe operation per network.

BOUNDARY SCAN TESTING

Boundary scan tests may be generated manually but are usually created using the Scan

Program Generator (SPG). The basic tests check the integrity of the chain on a UUT. Other

tests can be generated that check for short circuits and open circuits on the PCB. Scan test

facilities are integral to the s790 and s790VXI test systems but can be run on upgraded s700

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test systems that have been fitted with VXI Scan Cards. Boundary Scan aims to overcome

access problems to components and to confirm:

• - correct operation of devices

• - correct interconnection between devices

• - correct interaction between devices

Boundary Scan is used because modern

technologies limit physical access through:

• - high pin count packages.

• - requirement for high accuracy pin placement.

• - surface mount technology means poor access.

• - conformal coating difficult to probe.

• - double sided boards can't use BON’s.

Need for visibility and Control to:

• reduce debug and test time.

• reduce test development time.

• reduce cost of test

LANGUAGES

Component Description Language

The Component Description Language provides component description facilities and library

management for test systems using components conforming to the IEEE 1149.1 standard. It

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enables the descriptions of scan components to be placed in a library and allows the

modification of existing components held in the library.

Board Description Language

The Board Description Language is a source language used to describe the individual

components on a board and the interconnections between them. With respect to boundary

scan, it contains details of what components form the scan chain and how the test access port

(TAP) connections are made. The source file must be compiled into object form for use with

the Scan Program Generator.

Fixture Data Language

The fixture data language is a source language used to prepare descriptions of test fixtures.

The source file must be compiled into object form for use with the Scan Program Generator.

Boundary Scan Definition Language

This is a subset of VHDL (Very High Speed Hardware Description Language) and is used to

describe the testability features of devices that comply with the IEEE1149.1 standard.

BSDL to CDL Translator

This allows the translation of Boundary Scan Description Language into DiagnoSYS’s

Component Description Language. The main purpose of the translator is to generate the scan

test section of the component description.

CONTEXT DEPENDENT PROBING

Context Dependent Probing (CDP) is used during Functional Digital Diagnostic Testing.

CDP gives benefits of a reduction in the number of probing operations needed to diagnose a

failure and provides accurate diagnostics in less time, which in turn gives cost benefits of

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higher throughput. The number of probe operations needed to diagnose a fault can be

reduced by a ratio of 5:1 or more.

CDP identifies which component(s) could contribute to a fault thereby determining which

component(s) to probe or ignore.

Context Dependent Probing (CDP) further improves the diagnostic capability of the

ANALYST probing algorithm by reducing the number of probes taken to diagnose a fault.

Improvements of 5:1 and more are feasible with these techniques.

CDP uses a 'diagnostic data build' technique which takes information from the Component

Descriptions for the devices on the board, the Trace Data file and the Board Description to

'build' the diagnostic data for a database. This information is used to identify control pins for

a device to be probed and therefore allow Analyst to probe these pins first. It also gives

information which allows Analyst to decide the order in which devices connected to a

network should be probed if that network should fail. This is done by matching Trace Data

for control pin(s) for devices with truth-table information taken from the Component

Description for each device, enabling an analysis to be made as to whether each device is

driving, sensing or tri-state at the failing measure index. Device inputs can also be set to

'ignore' status, by this analysis, if they do not affect the device outputs at the failing measure

index.

Diagnostic data is held in a Diagnostic Details file which can be user modified via menu

selections in the Probe Display window.

SIMULATORS

A simulator provides a ‘software’ model of a circuit. It allows the programmer to write input

test vectors (patterns) and present them to the simulator which then calculates the internal

and external nodal activity generated. The simulator has full knowledge of the logical activity of 91

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in the circuit which makes it possible to automatically check the ability of the manually

written test vectors to detect and diagnose faults within the circuit.

Fault Lists and Fault Dictionary

The simulator generates a list of all possible faults in the circuit called a Fault List. It then

applies each fault in turn to the software model and then runs the test program to check

whether or not they are detected and then diagnosed. When a fault is detected it is marked as

‘found’ and the resulting vector on the outputs of the circuit is recorded against the fault

cause in a Fault Dictionary.

CADDIF

Simulator Links translate the Simulator created files into an intermediate format called

CADDIF (Computer Aided Design Data Interchange Format) via a Simulator Port.

The CADDIF standard Defines a neutral format for test data allowing it to be independent of

either the tester or simulator computer platform. The CADDIF standard is public domain

information which allows an open architecture concept between simulators and ATE in

general.

CONCLUSION

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ATE automatic test equipment is a vital part of the electronics test scene today. Automatic

test equipment enables printed circuit board test, and equipment test to be undertaken very

swiftly - far faster than if it were done manually. As time of production staff forms a major

element of the overall production cost of an item of electronics equipment, it is necessary to

reduce the production times as possible. This can be achieved with the use of ATE, automatic

test equipment.

Automatic test equipment can be expensive, and therefore it is necessary to ensure that the

correct philosophy and the correct type or types automatic test equipment are used. Only by

applying the use of automatic test equipment correctly can the maximum benefits be gained.

Each type of automatic test philosophy has its strengths, and accordingly it is necessary to

choose the correct type of test approach for the testing that is envisaged.

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project report

Documents

project report report

project report introduction

bel page

project report prefacewith

project report certificatethis

project report contents1

project guides

evaluated project training