HART Communication

INTRODUCTION
For many years, the field communication standard for process automation equipment has been a milliamp (mA) analog current signal. The milliamp current signal varies within a range of 4-2OmA in proportion to the process variable being represented. Li typical applications a signal of 4mA will correspond to the lower limit (0%) of the calibrated range and 2OmA will correspond to the upper limit (100%) of the calibrated range. Virtually all installed systems use this international standard for communicating process variable information between process automation equipment.

HART Field Communications Protocol extends this 4- 2OmA standard to enhance communication with smart field instruments. The HART protocol was designed specifically for use with intelligent measurement and control instruments which traditionally communicate using 4-2OmA analog signals. HART preserves the 4- signal and enables two way digital communications to occur without disturbing the integrity of the 4-2OmA signal. Unlike other digital communication technologies, the HART protocol maintains compatibility with existing 4-2OmA systems, and in doing so, provides users with a uniquely backward compatible solution. HART Communication Protocol is well-established as the existing industry standard for digitally enhanced 4- 2OmA field communication.

- AN OVERVIEW

HART is an acronym for "Highway Addressable Remote Transducer". The HART protocol makes use of the Bell 202 Frequency Shift Keying (FSK) standard to superimpose digital communication signals at a low level on top of the 4-2OmA. This enables two-way field communication to take place and makes it possible for additional information beyond just the normal process variable to be communicated to/from a smart field instrument. The HART protocol communicates at 1200 bps without interrupting the 4-2OmA signal and allows a host application (master) to get two or more digital updates per second from a field device. As the digital FSK signal is phase continuous, there is no interference with the 4- 2OrnA signal.

HART is a master/slave protocol which means that a field (slave) device only speaks when spoken to by a master. The HART protocol can be used in various modes for communicating information to/from smart field in3truments and central control or monitor systems. HART provides for up to two masters (primary and secondary). This allows secondary masters such as handheld communicators to be used without interfering with communications to/from the primary master, i.e. control/monitoring system. The most commonly employed HART communication mode is master/slave communication of digital information simultaneous with transmission of the 4-2OmA signal. The HART protocol permits all digital communication with field devices in either point-to-point or multidrop network configuration. There is an optional "burst" communication mode where single slave device can continuously broadcast a standard HART reply message.

HART COMMUNICATION LAYERS

The HART protocol utilizes the OSI reference model. As is the case for most of the communication systems on the field level, the HART protocol implements only the Layers 1, 2 and 7 of the OSI model. The layers 3 to 6 remain empty since their services are either not required or provided by the application layer 7

Aluminum Electrolytic Capacitors (electronics seminar topics)

Aluminium electrolytic capacitors are widely used in power supply circuitry of electronic equipment as there after several advantages over other types of capacitances. The selection of a capacitor for an application without knowing the basics may result in unreliable performance of the equipment due to expanitor problems. It may lead to customer dissatisfaction and damage market to potential or the image of a reputed company. The aluminium eletrolytic capacitors are suitable to be used when a great capacitance value is required in a very small size. The volume of an electrolytic capacitor is more than 10 times less than a film one considering the same rated voltage and capacitance. The cost per F is also less when compared with all other capacitors.

CONSTRUCTION

An aluminium electrolytic capacitor is composed of high-purity, thin aluminium foil (0.05 to I mm thick) having a dieletric anidation on its surface to prevent current flow in one direction. This outs as anode. Another these two aluminium coils is an electrolytic impregnated paper, which cuts as the dieletric. Since the capacitors is inversely propotional to the dieletric thiclenen. And the dieletric thicknen is propotional to the forming voltage, the relationship between capacitance and cerming voltage is.

CAPACITANCE=VOLTAGE

Aluminium tabs attached to the anode and cathode coils act as the positive and negative leads of the capacitor respectively. The entire element is sealed into an aluminium can by using rubber, bakelite or phenolic plastic. The construction of an aluminum electrolytic capacitor is the following:

The anode (A):

The anode is formed by an aluminium foil of extreme purity. The effective surface area of the coil is greatly enlarged (by a factor upto 200) by electrochemical etching in order to achive the maximum possible capacitance values.

The dieletric (O):

The aluminum foil (A) is covered by a very thin oxidised layer of aluminium oride (O=Al O3. This oxide is obtained by means of an eletro chemical process. The typical value of forming voltage is 1.2 nm/v. the oxide with stands a high electric field strength and it has a high dielectric constant. Aluminium oxide is therefore well suited as a capacitor dieletric in a polar capacitor. The A12O3 has a high insulation resistance for voltages lower than the forming voltage. The oxide layer consistitutes a nonlinear voltage dependent resistance: the current increases more steeply as the voltage increases

The electrolytic Paper, cathode (C,K)

The negative electrode is a liquid electrolyte absorbed in a paper. The paper also acts as a spacer between the positive foil carrying the dieletric layer and the opposite Al-foil ( the negative Coil) acting as a contact medium to the eletrolyte. The cathode foil serves as a large contact area for passing current to the operating eletrolyte. Bipolar Al electrolytic capacitors are also available. In this designs both the anode foil and cathode foil are anodized. The cathode foil has the same capacitance rating as the anode foil. This construction allows for operation of direct voltage of either polarity as well as operation of purely alternating voltages. Since it causes internal heating the applied atternating voltage must be kept considerably below the direct voltage rating. Since we have the series connection of two capacitor elements, the total capacitance is equal to only half the individual capacitance value. So compared to polar capacitor, a bipolar capacitor requires upto twice the volume for the same total capacitance.

Chip Morphing(SEMINAR TOPIC FOR EC)

role of energy

Engineering is a study of tradeoffs. In computer engineering the tradeoff has traditionally been between performance, measured in instructions per second, and price. Because of fabrication technology, price is closely related to chip size and transistor count. With the emergence of embedded systems, a new tradeoff has become the focus of design. This new tradeoff is between performance and power or energy consumption. The computational requirements of early embedded systems were generally more modest, and so the performance-power tradeoff tended to be weighted towards power. "High performance" and "energy efficient" were generally opposing concepts.

However, new classes of embedded applications are emerging which not only have significant energy constraints, but also require considerable computational resources. Devices such as space rovers, cell phones, automotive control systems, and portable consumer electronics all require or can benefit from high-performance processors. The future generations of such devices should continue this trend.

Processors for these devices must be able to deliver high performance with low energy dissipation. Additionally, these devices evidence large fluctuations in their performance requirements. Often a device will have very low performance demands for the bulk of its operation, but will experience periodic or asynchronous "spikes" when high-performance is needed to meet a deadline or handle some interrupt event. These devices not only require a fundamental improvement in the performance power tradeoff, but also necessitate a processor which can dynamically adjust its performance and power characteristics to provide the tradeoff which best fits the system requirements at that time.

PROCESSOR PERFORMANCE

These motivations point to three major objectives for a power conscious embedded processor. Such a processor must be capable of high performance, must consume low amounts of power, and must be able to adapt to changing performance and power requirements at runtime.

The objective of this seminar is to define a micro-architecture which can exhibit low power consumption without sacrificing high performance. This will require a fundamental shift to the power-performance curve presented by traditional microprocessors. Additionally, the processor design must be flexible and reconfigurable at run-time so that it may present a series of configurations corresponding to different tradeoffs between performance and power consumption.

MORPH

These objectives and motivations were identified during the MORPH project, a part of the Power Aware Computing / Communication (PACC) initiative. In addition to exploring several mechanisms to fundamentally improve performance, the MORPH project brought forth the idea of "gear shifting" as an analogy for run-time reconfiguration. Realizing that real world applications vary their performance requirements dramatically over time, a major goal of the project was to design microarchitectures which could adjust to provide the minimal required performance at the lowest energy cost. The MORPH project explored a number of microarchitectural techniques to achieve this goal, such as morphable cache hierarchies and exploiting bit-slice inactivity. One technique, multi-cluster architectures, is the direct predecessor of this work. In addition to microarchitectural changes, MORPH also conducted a survey of realistic embedded applications which may be power constrained. Also, design implications of a power aware runtime system were explored.

Solar Power Satellites(mechanical seminar topic)

The new millennium has introduced increased pressure for finding new renewable energy sources. The exponential increase in population has led to the global crisis such as global warming, environmental pollution and change and rapid decrease of fossil reservoirs. Also the demand of electric power increases at a much higher pace than other energy demands as the world is industrialized and computerized. Under these circumstances, research has been carried out to look into the possibility of building a power station in space to transmit electricity to Earth by way of radio waves-the Solar Power Satellites. Solar Power Satellites(SPS) converts solar energy in to micro waves and sends that microwaves in to a beam to a receiving antenna on the Earth for conversion to ordinary electricity.

SPS is a clean, large-scale, stable electric power source. Solar Power Satellites is known by a variety of other names such as Satellite Power System, Space Power Station, Space Power System, Solar Power Station, Space Solar Power Station etc. One of the key technologies needed to enable the future feasibility of SPS is that of Microwave Wireless Power Transmission.WPT is based on the energy transfer capacity of microwave beam i.e, energy can be transmitted by a well focused microwave beam. Advances in Phased array antennas and rectennas have provided the building blocks for a realizable WPT system.

Increasing global energy demand is likely to continue for many decades. Renewable energy is a compelling approach - both philosophically and in engineering terms. However, many renewable energy sources are limited in their ability to affordably provide the base load power required for global industrial development and prosperity, because of inherent land and water requirements. The burning of fossil fuels resulted in an abrupt decrease in their .it also led to the green house effect and many other environmental problems. Nuclear power seems to be an answer for global warming, but concerns about terrorist attacks on Earth bound nuclear power plants have intensified environmentalist opposition to nuclear power.

Moreover, switching on to the natural fission reactor, the sun, yields energy with no waste products. Earth based solar panels receives only a part of the solar energy. It will be affected by the day & night effect and other factors such as clouds. So it is desirable to place the solar panel in the space itself, where, the solar energy is collected and converted in to electricity which is then converted to a highly directed microwave beam for transmission. This microwave beam, which can be directed to any desired location on Earth surface, can be collected and then converted back to electricity. This concept is more advantageous than conventional methods. Also the microwave energy, chosen for transmission, can pass unimpeded through clouds and precipitations.

SPS
The concept of a large SPS that would be placed in geostationary orbit was invented by Peter Glaser in 1968. The SPS concept was examined extensively during the late 1970s by the U.S Department of Energy (DOE) and the National Aeronautics and Space Administration (NASA). The DOE-NASA put forward the SPS Reference System Concept in 1979. The central feature of this concept was the creation of a large scale power infrastructure in space, consisting of about 60 SPS, delivering a total of about 300GW.But, as a result of the huge price tag, lack of evolutionary concept and the subsiding energy crisis in 1980-1981, all U.S SPS efforts were terminated with a view to re-asses the concept after about ten years. During this time international interest in SPS emerged which led to WPT experiments in Japan.

transmit mixer and concrete pump

In a Ready Mix Concrete (R M C) batching plant, there are two units.
1. Mixing unit
2. Delivery unit

The transit mixer and concrete pumps are the delivery units of a RMC plant. The transit mixer used to deliver the RMC of same workability and quality at work site and the concrete pump is used to deliver the RMC at the desired place as per requirements. Before discussing about Transit mixer and concrete pump, must discuss about the significance of RMC

mechanism

The mechanisms of deterioration of concrete due to various physical, chemical, biological and environmental pollutants are widely researched. In search of possible reasons of non performance of concrete on the face of such voluminous researched. It is necessary to recognize the interactive nature of various factors such as there is interaction between various aggressiveness temperature and humidity as well as the nature of resultant concrete, e.g. PH value, chloride bounding, electrical resistivity etc. The distress to concrete structures is quiet often due to non adherence to the requirements of specifications. The areas a of non compliance not only related to the appropriateness of ingredients of concrete , adequacy of mix properties, but also to workmanship-notably placing, compaction and curing of concrete. Specifications are often difficult to check on site. That results in difficulties is ensuring compliances of specifications and certainty regarding quality achieved. RMC can play a significant role in ensuring quality and durability of concrete that goes in to the structures.

RMC is a revolutionary product, which metamorphosed the entire construction industry. It is a factory made, quality product produced by skilled persons with the help of advanced state-of-the art of technology.

The advanced state-of-the art of technology means play of machineries for the fruitful production of RMC. The RMC plant mixer should always computerized. Here only deals about the transit mixer and concrete pump - the delivery units of RMC-.

Transit mixer that ensure timely delivery of concrete of same workability and quality at the work site.

The concrete pump is used to deliver the concrete at the desired place as per requirements.

The name itself gives a picture of the machine. Basically it is a vehicle with a rotating mixing drum. The drum is rotating during the traveling of the vehicle to the work site. This rotation of the mixer drum ensures the concrete of same workability and quality. Transit mixer used only in RMC plants and which timely deliver the concrete to the work site.

Parts of transit mixer.

1. Auxiliary frame.
2. Discharge support.
3. Detachable feed hopper.
4. Crank chute support.
5. Swiveling discharge chute.
6. Additional extension chute.
7. Bearing pedestals.
8. Drum bearing.
9. Water tank support.
10. Water tank.
11. Mixing drum.
12. Rollers.
13. Water pump.
14. Diesel engine.
15. Suction filter
16. Control cabinet.

MICRO-ELECTROMECHANICAL SYSTEMS

SUMMARY
MEMS are already used as accelerometers in automobile air-bags. They've replaced a less reliable device at lower cost and show promise of being able to inflate a bag not only on the basis of sensed deceleration but also on the basis of the size of the person they are protecting. Basically, a MEMS device contains micro-circuitry on a tiny silicon chip into which some mechanical device such as a mirror or a sensor has been manufactured. Potentially, such chips can be built in large quantities at low cost, making them cost-effective for many uses.

Introduction
Among the presently available uses of MEMS or those under study are:

Global position system sensors that can be included with courier parcels for constant tracking and that can also sense parcel treatment en route .
Sensors built into the fabric of an airplane wing so that it can sense and react to air flow by changing the wing surface resistance; effectively creating a myriad of tiny wing flaps .
Optical switching devices that can switch light signals over different paths at 20-nanosecond switching speeds
Sensor-driven heating and cooling systems that dramatically improve energy savings .
Building supports with imbedded sensors that can alter the flexibility properties of a material based on atmospheric stress sensing .

SMART BOMBS(MECHANICAL SEMINAR TOPIC)

Introduction

Smart bombs are weapons capable of destroying enemy targets with out the need for a launch aircraft to penetrate the envelops of the air defense systems. These essentially comprise a terminal guidance unit that guides them in the last phase to achieve pinpoint accuracy. Increased accuracy means that a single, moderate-size bomb can give a better result than multiple strikes with larger, non-guided bombs.

Smart bombs are desirable both from ethical and tactical standpoints. On ethical grounds, the military desires that each warhead deployed should strike only its indented target so that innocent civilians are not harmed by misfire. From tactical standpoint, it wants weapons with pinpoint accuracy to inflict maximum damage on valid military targets and minimize the number of strikes necessary to achieve mission objectives. Gravity bombs with laser or GPS/INS guidance are smart bombs that have changed the face of modern warfare

Laser-Guided Bombs
Laser-guided bombs have an internal semi-active guidance system that detects laser energy and guides the weapon to the target illuminated by an external laser designator.Laser designators radiate a narrow beam of pulsed energy in the near infrared wavelength spectrum. These are semi active illuminators used to tag the desired spot. These can be aimed such that laser energy precisely designates the chosen spot on the target. Laser designator can be located in the delivery aircraft, another aircraft or on a ground source.

Typical LGB seekers comprise an array of photo diodes to decode the laser pulsed repetition frequency (PRF) and derive target position signals. Laser designators and seekers use a pulse coding system to ensure that a specific seeker and designator combination work in harmony. By setting the same code in both the designator and the seeker will track only the target designated by the chosen designator.

Laser designators provide precision target marking for air support. LGBs with TV or infrared seeker in their nose show the target to the attacking pilot on a screen in the cockpit. The pilot fixes cross hairs on the target and marks it for the weapon to aim at. The target scatters the received laser energy in all the directions. LGB seeker having a limited field of view receives a small part of the scattered energy and decodes it. If the received PRF code matches the preprogrammed code, the pilot fires the bomb. It then horns onto the reflected laser energy to attack the target

Some LGBs require laser target illumination before launch or release and/ or during the terminal portion of flight. The LGB flight path can be divided into three phases: ballistic, transition, and terminal guidance.

During the ballistic phase, the weapon continues on the unguided trajectory established by the flight path of the delivery aircraft at the moment of release. In this phase, the delivery altitude takes on additional importance, since maneuverability of the unguided bomb is related to the weapon velocity during terminal guidance. Therefore, airspeed lost during the ballistic phase equated to a proportional loss of maneuverability. So the closer to the target the release of the bomb, the more the accuracy of the bomb

The transition phase is where initial acquisition of the designating laser takes place. During this phase, the weapon attempts to align its velocity vector with the line of sight vector to the target. Once a lock has been achieved, the guidance system uses the canards to try and keep the bomb within the cone of the reflected laser energy.

The terminal phase is when the reflected laser centers on the seeker causing the bomb to dive to the target. LGBs are excellent performers in dive deliveries initiated from medium altitude. A steep, fast dive attack increases LGB maneuvering potential and flight ability. Medium-altitude attacks generally reduce target acquisition problems and more readily allow for target designation by either ground or airborne designation platforms. Medium-altitude LGB dive delivery tactics are normally used in areas of low to medium threat.

LGBs miss the target if the laser is turned on too early: During certain delivery profiles where the LGB sees laser energy as soon as it is released, it can turn from its delivery profile too soon and miss by failing short of the target. To prevent this, the laser designator must be turned on at the time that will preclude the bomb from turning down toward the target prematurely. Normally, the pilot knows the proper moment for laser 'on'. The specific LGB and the delivery tactics of the attacking aircraft dictate the minimum designation time required to guide the weapon to the intended target.

The four basic requirements for effective use of laser designators with LGBs are:
1. The PRF code of the laser designator and the LGB must be compatible
2. A direction of attack must be determined because the LGB must be able to sense sufficient laser energy reflecting from the target being designated.
3. The laser designator must designate the target at the correct time.
4. The delivery system must release the weapon within the specific weapon's delivery envelope.