Monday 12 November 2012


सब घट मेरा साईयां, खाली घट ना कोय !

बलिहारी उस घट की, जा घट परगट होय !

(God is present in every human beings  but blessed is the human being

where it reveals itself )

(I)    The  moment a girl completes 18 years, she can –

(a)    sell tobacco made products  (सिगरेट की दुकानों पर

लिखा होता है कि 18 वर्ष से कम तम्बाकू बेचना अपराध है )

(b)     marry   of her own choice

(c)   drink

(d)  drive

(e)    vote


(II)   The moment  a person becomes enlightened

(I mean he  sees his palpable God or the Light of the formless God,

which Lord Buddha and others have seen),   his all kinds of FEAR  

  disappears  such as –

(a)     fear of death – his own or death of near and dear  one  (डूबने का डर अगर,

मुझको हो तो कैसे हो ? मैं   तेरा, कश्ती तेरी, साहिल तेरा और दरिया भी तेरा )

 (when a flower dies, we do not cry. We know it is impermanent)

चाहे निकल जाये हमारी body  से प्राण रे

(b)    fear of insult/criticism by others (लोग क्या कहेंगे )

(c)    fear of losing physical/materialistic assets (रोटी, कपड़ा और मकान आदि )

(d)   fear of security/career of children/brothers/sisters etc.

फानूस बन कर जिसकी हिफाजत खुदा करे !
वो शमा क्या बुझे जिसे रोशन खुदा करे !



(III)  All the qualities mentioned in Part I, II and III of my blogs can also 

be present in   a highly spiritual Person moving toward enlightenment

 (may be for some other reasons like being honest due to earning

 reputation/fear of police arrest etc.) . But the quality ‘ABSENCE OF FEAR’ 

is the only quality which separates an Enlightened Person from a highly

spiritual person.  

जैसे आपके घर के बाहर एक कूड़ा करकट का ढेर लगा हो कोई आन्धी आये और

सारा कूड़ा करकट ले जाये ! जैसे जीवन में कोई क्रांति आ जाये !

Similarly, fear disappears after enlightenment.  



(IV)   When the fear disappears,

(a)    his life becomes more transparent. With fear,   his personal desires/greed

also disappears.  He has   nothing to lose.  He knows that if some thing is

shameful to reveal, it is more shameful to hide.

(b)     he is not perturbed what is happening in life.  He becomes a witness only. 

When we see a movie, we know that these are not real things,

so we are not perturbed.  Life becomes a movie for him

(c)   Or say life becomes a dream for him. If, in a dream, my friend  borrows

a 100 rupee note from me, after wake up, I will not ask him to return.

At the core of his heart, he is not bothered as to who is harming him financially,

emotionally, physically etc.. Though for day-to-day practical behavior

with the worldly people, he may behave like a worldly person.

But a noticeable  difference can be felt in his behavior.

(d)  he does not feel any special  attraction for his family members.

He retains only compassion for them.  

                    सीने पर रख हिज्र का पत्थर चुपचाप !
                  
                     घर में रह और छोड़ दे घर चुपचाप !!

                 (हिज्र -  separation)

(e)     his universe  becomes  full of joys – both outer and inner. The common

quality in all the mystics was that they were full of love.

ताकत की जरूरत तब होती है जब किसी का बुरा करना होता है वर्ना सब

काम प्रेम से हो जाते हैं ! परमात्मा में डूबे हुये इंसान को संसार कैसे समझ सकता है

उसकी अलग दुनिया होती है !

सारे नशे उतर जाते जब होती  प्रभात् 

नाम खुमारी नानका  चढ़ी रहे दिन रात्

Only human beings love. Animals do not love. भैंसों में  Romeo Juliet, हीर- रांझा

 तथा लैला मजनूं के कहानियां नही होती !  और आजकल तो human beings में भी

प्यार एक या दो साल से ज्यादा नही चलता ! ज्यादा आंसू नहीं बहाये जाते ! 

कुर्बानी की बात पर तो हंसी आती है ! हर कोइ किसी का Ex  है !  Break-up  या Dump  

करना आम बात है !

केवल अपने मान सम्मान को विचारने वाला प्रेम नहीं कर सकता !

प्रेम का आधार तो त्याग और बलिदान होता है  A E.P.,  full of selfless

divine   love,    might  refuse to pluck a fruit from a tree and would

rather   wait till it ripens and falls off.

Saturday 10 November 2012

Principle of differential flow-meter

hello friends

here i have uploaded video which describes basic principle behind the orifice, nozzle, venturi type flow meters. Actually designs of flow meters can be changed with other manufacturers. The manufacturer of the flow meter described in above video is Endress + Hauser.

The videos of other types of flow meters will be uploaded soon...

I hope you all will enjoy and understand the principle behind it. If you have any query than you can ask to me bt HA QUESTIONS TOUGH NAI HONA CHAHIYE...LOLZZZ

Have a great day...





Saturday 20 October 2012

Life @ Larsen & Toubro Construction

Hello Dosto,Mitro Bhaio nd Behno...:)

                     Today finally got some time to share my experience @ L&T Construction as a "fresher"...


                     Generally the Campuses start from our 7th sem onwards only...So its very important to clear ur ATKT's b4 them + U will need some "BUTTERING SKILLS" for clearing PI's also for any company..

                     1 such company was L&T that came to our campus in 7th semester.. Firstly i cleared the written exam(By luck ;)) then went for an interview @ Baroda . There after clearing the PI i got an letter of appointment @ Powai campus.

                     Before 20 days of joining powai campus they told me to report @ chennai campus which came as a shock for me as i had already prepared for powai campus!! We called up L&T & they always said only one line "DON'T WORRY L&T WILL TAKE CARE OF U".. so jst believing this one line & L&T i went to Chennai By flight nd reached the hotel they booked for all of us..

After reaching hotel we realised that L&T has kept its word of "TAKING CARE". such rooms were booked for us..


                     They were fully AC rooms wid early breakfasts complimentary + free transport to office <=> hotel in buses or cars was also provided for some period of time.. We all had a great Tym during our stay in hotels..
                     NOW!! All orientation nd all completed we were alloted our department nd divisions & units nd their respective locations.. some of them were shifted to site of some other locations while i had to stay in Chennai only...
                     I m in Enginnering Design & Research Centre(EDRC), Chennai HQ..exactly speaking I m in Power transmission & distribution unit & my work is in Testing & Commissioning team for all instrumentation side work on any site. It includes testing of field instruments + PLC+DCS+SCADA+HMI etc... So work wise m satisfied.. 

NOTE:-U R NOT GIVEN ANY CHOICE/PREFERENCE OF DEPT OR LOCATION SO ITS UR LUCK AS ITS A VERY HUGE COMPANY SO B READY TO WORK IN ANY DEPT OR ANY LOCATION & L&T CONSTRUCTION TAKES ALL UR ORIGINAL DOCS FOR BOND PERIOD.

                     The office starts @ 9am nd its good to have some frndly seniors as they all joined same as u GET's so u can njoy coffee nd tea @ any point of tymin office.. as a GET u r provided full freedom for tympass..:)  no responsibilities nothing much it all depends on ur interests ..we have lunch together nd @ 5:30 everyday some new snacks r provided on ur table so u can have lot of different snacks everyday before leaving office.. the tyming for leaving office r not sure.. u can decide it upon ur boss mood (as i do).:P

                     I given stay @ a house where all other GET's share... I know u will be excited to know how this new place it is.. is it d same as earlier??  NOOOOOO!!!!! all dreams came crashing when i came to room the first day... as all r young none cares of any cleanliness or anything.. The drainage was not working properly!! The fan was not operating @ appropriate speed!! & the most horrible scene when i saw my BED!! THERE WAS NO MATTRESS NOR PILLOW nothing!!! 



                     Some how i m still managing to sleep without matress as the market is away & no tym.. getting some dinner packets daily..Njoying the rainy season here.. The office atmosphere is good the bosses r good.. they r supportive nd helping...slowly & gradually getting set in this TAMIL environment of "lunghi" nd "mogre ka gajra's" ;) :) :D....

BUT!! BUT!! BUT!! how can u forget that a testing & commissioning engineer has nothing to do in office!!!! he has to go to site to inspect!!! so they sent me for some testing experience @ IIT,MADRAS for an instrument that came from spain.. it lasted for 2 days.. nd believe me wearing formals @ site jst makes u more frustrated.!!!
                     Any how did all testings nd cam to office made sm reports etc.. nd now again a new place to go for testing.. this tym going to TATA STEEL,JAMSHEDPUR for sm months till it gets over...

So now will visit site.. Experience it & then again share wid u all as soon as possible...:)

MORAL & SUMMARY: 


                     L&T is a very good company to start off with it will be paying u good amount + u can have hands on experience on all the things without worrying of any damage respo..:P it provides all monetary support for ur accommodation & transport etc... BUT as u r not given any preference or chance there r possiblites that u will b given some place where there is no relevant work or experience for u (Such can be handled if u have some Jack on some higher posts then its possible)....

Saturday 6 October 2012

At L&T its all about "Imagineering"


Hello friends…!!
Here I want to share my corporate life’s experience with all of you.
         At earlier I was selected by L&T in campus interview of our college. There was very wonderful experience in my interview also. At the end of the 8th semester company send me joining letter. I was very excited because my joining place was Mumbai.
         On 13th July I had to report at Mumbai office. Before one day prior to joining I was reach there for accommodation purpose. L&T have their own building with all pleasing facilities like gymnasium, common dining room, indoor as well as out door games facilitation, common TV room(where we all are fighting  to switch the channel we fond...but when any cricket match is there then we enjoy together!!!).
At the first day of my job when I came at L&T-Powai (Mumbai)  campus it was great pleasure to my self its about 100 acres campus with all facility like canteen , bank , sports club, library(which is biggest library in corporate world) etc. My first day was passed in documentation process. After that day our training program was started called “PRAYAG”. I think that it was longest training program in any company. Students from different states were there. We were divided in various groups. We had to do various group activities during this period viz. Roll plays, mimicry, technical presentation, poster making etc. There were also experts lecture are held (very boring as usual!!).
         Now about L&T…there are total nine independent companies (IC) under the umbrella of L&T like
   1)  Heavy Engineering Department (HED) - in it various types of job work is done like manufacturing of heavy pressure vessels, boiler, modular plant for oil & gas industries. These manufacturing units are situated at Hazira (600acres) campus, Katupalli-Chennai(1100acres) campus, and also at in gulf countries like Abu Dhabi, Oman, Sharjah etc. L&T defense is also under this department which is pioneer in making of submarine (INS Arihant) missiles (Brahmosh, Pinaka etc.) for Indian Defense and space satellite (PSLV) etc. for ISRO.
   2)  Hydro Carbon- I am also working in this department in mid & down stream. In this department we have to build various refinery(Reliance Jamnagar, IOCL Panipat, ONGC  mangla-Rajasthan), fertilizer plant(GNFC Bharuch, NFL Panipat) all are build by L&T. Mumbai High is floating platform to explore oil from see is built by L&T.
   3)   Electrical & Automation – various types of switch gear, protection circuit is build in this department.
   4)   Metallurgy and Material handling IC – control valve, mining equipment like excavator (L&T Komatsu)   Large trucks (Scania) are manufactured under this dept.
   5)   L&T construction -most profitable business of L&T which is working on different project like Mumbai Mono rail, Delhi Metro, Highway and road project etc.
   6)   L&T  InfoTech – IT division of L&T
   7)   L&T MHI (Mitsubishi Heavy Engineering )
   8)   Tractor Engineering Ltd.
   9)   Rubber Processing Machinery

         Now a days I am working in the Hydrocarbon mid & down stream department and working on a refinery project of SARB at Abu Dhabi with collaboration to GS, Korea (Hydrocarbon unit of LG electronics).

  Regards,
 Anilkumar G. Shah
    

                                                                                                                                                       


R&D Block / Ground Floor / Gate No. 01 Powai, Mumbai - 400 072    
 Email:Anilkumar_Shah@Lntenc.com


PLC Programing Refresher

Here is the pdf file for refreshing PLC programing concepts in brief.

Credits : - Shreyansh Jayani

Do subscribe or follow us to get latest updates regarding such topics...
PLC Programming Refresher

Monday 1 October 2012

Differentiate:-Relay, Contactor and Circuit Breaker

                  Relay and contactor have the same function, to close a circuit with a logic signal (applied to the coil). Circuit Breaker has another main function, to protect a circuit for over currents. In most cases, the breakers are operated manually. The relays and contactors are not operated manually. Relays are used in circuits to close a single circuit, contactors to close a three phases circuit (motors).

                  Relays and contactors are control elements, i.e. you control the current (On/Off) in the attached device with a control signal. Normally, relays are for low power applications (voltage x current) while contactors are for higher voltages and currents. You might see components called "Contactor Relays" which in fact are contactors for control applications. 

                  Circuit Breakers are protection elements. They protect the downstream connected devices from overload current, short circuit current, leakage current.. There are also several types of Circuit Breakers: Miniature CB (which you have at your appartment in the power distribution board. There are also Molded Case CB's and Air Circuit Breakers.. and so on to Medium and High voltage breakers.


Most circuit breakers are thermal devices that when excess current run through them they heat up and trip (open up).They can also be used as a switch to open a circuit.A contactor is a electric relay that is essentially a solenoid and a pair of electrical contacts. The solenoid is activated and it closes the contacts 
Relay is the device acttached to any circuit which makes it work automatically.it has less operating voltage but in contactor it works on the principle of cantact making that either single phase voltage or 110v ac supply , the plunger makes the other three phase contact and thus operates on some high operating voltage
Contactor is a switching device. Unless & until you give command it wont operate. Contactor is not a sensing device. on the other hand Relay is the device which sense the abnormality & give command accordingly. Relay differentiate normal & abnormal condition which contactor can not.In short if only contactor is connected in circuit.. in case of abnormal like OV or OC it will burn.. but if it is connected in coordination with relay.. relay will sense the fault & give signal or command to contactor to trip  
Relays and Contactors are electromagnetic switches. The only difference is that relays are usually used for low voltage applications while contactors are used for higher voltage application. Contactors usually have Overload protection.

Some examples :-

Relays are use as electromagnetic switches to control certain parts of a circuit (low voltage application). A better example would be such as if you want your circuit to sound a horn when a certain abnormality is happening at a certain period of time, then depending how you set up your circuit, a specific relay will either open or close and you horn will start making the sound. -Contactors can be used for example, to start motors or a number of motors that require a higher voltage in order for the motor or motors start working. In the example that I just gave, contactors work as starters. 

The first question should be the LOAD conditions to determine which component to use - relay, contactor or breaker - and the function of the product. 

-Relays are somewhat limited to the load characteristics. 
-Contactors in simple terms are just BIG relays able to handle larger loads. 
-Breakers are a safety device, when load conditions exceed contact capability and the breaker "opens". 



                                                                    RELAY
                  

                      4 Channel Relay Card 








                                Contactors




 
                                              Siemens Contactors



                           
                          Circuit Breakers



Thursday 27 September 2012

Wireless Charging Technology: What & How?


                 Wireless Charging (also known as " Inductive charging ") uses an electromagnetic field to transfer energy between two objects. This is usually done with a charging station. Energy is sent through inductive coupling to an electrical device, which then can use that energy to charge batteries or run the device.
Induction chargers typically use an induction coil to create an alternating electromagnetic field from within a charging base station, and a second induction coil in the portable device takes power from the electromagnetic field and converts it back into electrical current to charge the battery. The two induction coils in proximity combine to form an electrical transformer.Greater distances can be achieved when the inductive charging system uses resonant inductive coupling.
With the announcement of integrated wireless charging in theLumia 920, Nokia hopes it will be a significant part of the proposition to turn heads from Android and iPhone. But unlike previous examples like the Palm Pre's Touchstone charger, Nokia has joined HTC, Sony, Samsung and others by adopting "Qi", a proprietary interface standard created by the Wireless Power Consortium.
Qi, pronounced "chee", comes from the Chinese symbol meaning energy flow and is designed to provide energy to devices through magnetic induction. This is a similar solution to the system that charges electric toothbrushes. (It's also a valuable and legal two-letter word in Scrabble.)
In simple terms, the base station includes an induction coil that creates an alternating electromagnetic field. Meanwhile, a similar coil within the device is able to pick up this field, convert the energy into current and use it to charge the battery.

Inductive Coupling

Inductive coupling uses magnetic fields that are a natural part of current's movement through­ wire. Any time electrical current moves through a wire, it creates a circular magnetic field around the wire. Bending the wire into a coil amplifies the magnetic field. The more loops the coil makes, the bigger the field will be.
If you place a second coil of wire in the magnetic field you've created, the field can induce a current in the wire. This is essentially how a transformer works, and it's how an electric toothbrush recharges. It takes three basic steps:
  1. Current from the wall outlet flows through a coil inside the charger, creating a magnetic field. In a transformer, this coil is called theprimary winding.
  2. When you place your toothbrush in the charger, the magnetic field induces a current in another coil, or secondary winding, which connects to the battery.
  3. This current recharges the battery.
You can use the same principle to recharge several devices at once. For example, the Splashpower recharging mat and Edison Electric's Powerdesk both use coils to create a magnetic field. Electronic devices use corresponding built-in or plug-in receivers to recharge while resting on the mat. These receivers contain compatible coils and the circuitry necessary to deliver electricity to devices' batteries.

A Splashpower mat uses induction to recharge multiple devices simultaneously


Wireless Electricity Transmission

Magnetic induction is a technology that you will probably remember from your physics classes at high school.
You need two coils, a transmitter coil and a receiver coil. An alternating current in the transmitter coil generates a magnetic field which induces a voltage in the receiver coil. This voltage can be used to power a mobile device or charge a battery.
The animation below shows how to build a wireless charging system using magnetic induction. Press > to start, and >> to move to the next slide. Take your time to watch the animation before you click the next slide.
You will see that products need more than coils and alternatining currents. For energy-efficient power transfer the phone must be able to shut down the transmitter when the battery is full. The phone, therefore, needs to send control signals to the charging station.
I recommend to look at slide 14 in particular. This slide show three different methods for aligning the transmitter- and receiver coils.

  A PPT showing how it actually works (click to play each slide)

Inductive Power Transmission

Dries van Wageningen and Eberhard Waffenschmidt, Philips Research
                    The basic principle of an inductively coupled power transfer system is shown in Figure 1. It consist of a transmitter coil L1 and a receiver coil L2. Both coils form a system of magnetically coupled inductors. An alternating current in the transmitter coil generates a magnetic field which induces a voltage in the receiver coil. This voltage can be used to power a mobile device or charge a battery.
                  The efficiency of the power transfer depends on the coupling (k) between the inductors and their quality (Q). (See also Figure of merit)
The coupling is determined by the distance between the inductors (z) and the relative size (D2 /D). The coupling is further determined by the shape of the coils and the angle between them (not shown).


An estimate of power consumption by wireless chargers.

POWER CONSUMPTION OF WIRED CHARGERS

Let’s first look at the power consumption of a classic mobile phone charger. These chargers are simple so-called “external power adapters”. A good source for data is the ENERGY STAR website. Here you will see that Energy Start compliant AC-DC adapters typically rate:
  • Efficiency @ max load: 72% on average for 5 Watt adaptors
  • Power consumption @ no load: 0.12W on average for 5 Watt adapters with a few exceptionally good adapters going down to 0.01 W
Suppose that you use the adapter for 1 hour per day, and that it remains plugged in for the rest of the day. That is not a good practice, but it is quite common to leave power adapters and cradles continuously connected to the mains.
You see that the total energy consumption is:

  • charging: 1 hour * 2 W / 72% = 2.8 Wh (this assumes that 5 W charger will supply, on average, 2 W during a complete charging cycle)
  • standby (no load): 23 hours * 0.12 W = 2.8 Wh
You see that standby power contributes significantly to the total energy consumption of a mobile phone charger.


WHAT ABOUT WIRELESS CHARGERS?

Our wireless chargers also contain an AC-DC power adapter. Let’s assume that is has the same efficiency (72%). Let’s also assumes that it has the same standby power (0.12 W). [footnote: Wireless chargers can have a much lower standby power, but this keeps the comparison easier.] The transfer efficiency of the wireless power link is typically 70%. And assume that the wireless charger replaces 2 wired chargers. The total energy consumption is:
  • charging: 1 hours * 4 W / 72% / 70% = 7.9 Wh (we are now charging 2 devices simultaneously)
  • standby (no load): 23 hours * 0.12 W = 2.8 Wh


HOW DOES THAT COMPARE WITH THE WIRED CHARGERS?

Total power consumption of two wired chargers: 2 * ( 2.8 + 2.8 ) = 11.2 Wh
Total power consumption of one wireless charger with two receivers: 7.9 + 2.8 = 10.7 Wh
You see that the total energy consumption is comparable. Although wireless transfer is obviously not as efficient as transport over a copper wire, wireless power transmitters saves standby power energy when the wireless transmitter replaces multiple external power adapters.


MORE DETAILED & TECHNICAL INFO COMING SOON.... B CONNECTED ....

           "WIRELESSLY"

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Monday 24 September 2012

Recruitment Through GATE 2013

Hello Friends,
 As you all might have heard about ongoing buzz regarding our PSU's (i.e. Public Sector Companies) are  undertaking there recruitment through GATE 2013 exams.

All interested candidates are requested to visit following link for more details regarding post, salary, company name etc.

http://www.allgovtjobs.in/2012/09/jobs-through-gate-2013-latest-psu-recruitment-2013.html

Ensure that you fill up registration forms for applying on time and keep us updated on this blog as well.


Tuesday 18 September 2012

Difference between PLC,DCS & SCADA

                   In the past the strength and weakness of both the automation technologies were well understood. So it was easy for engineers to select the one that suits their application, but now due to the advent of microprocessors both the technologies are merging.The requirements which are thought to be exclusive to one technology can be found in the other one too.But still there are some things which are to be checked out before selecting the one that suits your application the best.

Now a days you cannot really tell the difference between a PLC or a DCS. Since the PLC was integrated with Analog I/O it crosses the boundary of being just digital and crosses to the realm of DCS in handling Analogs, Bus Systems, Distributed I/O and etc. Also, since the DCS now handles logics of Digital I/O it also crossed the boundary to the realm of PLC.

As you know PLC as to its name Programmable Logic Controller. Its main purpose is to replace the relay logic controls which is "On" or "Off". And DCS "Distributed Control Systems" its emphasis is Fast analog handling because of communications through Bus systems, networking and etc.

Summarizing all these, PLC = DCS......BUT still there are basic differences as below

PLC is a programmable Logic controller which is used mainly for interlocking different equipments.PLC using for perticular mechine or production unit.PLC is economicaly low cost.PLC'S can handle analog and digital I/O as earliear it could handle only digital.PLC'S are automatic controllers which is a substitute to hard wired controllers.they are extensively used for automation.PLC is for stand alone sytem.PLC is used Commonly with On\Off (Digital) Control and may be expanded with Analog I\O Modules for Analog Control and used for a control task.
                                      Programmable Logic Controller



DCS: DISTRIBUTED CONTROL SYSTEMS: THIS SYSTEM DOES WHAT A
PLC WOULD DO, BUT THE DIFFERENCE IS THAT A DCS IS USED IN
MUCH LARGER AND COMPLEX APPLICATION E.G: POWER GENERATION,
SOME COLD ROLLING MILLS etc.


DCS is the System in which controller are distributed geographically and integrated all the control hardwares .which is connected from the various field devices .DCS having its own network, Controller and HMI etc….Honeywell, Yokogawa, Invensys, ABB, Emerson are the leading .DCS Vendors.DCS is the System in which controller are distributed geographically and integrated all the control hardwares which is connected from the various field devices.DCS having its own network, Controller and HMI etc…Honeywell, Yokogawa, Invensys, ABB, Emerson are the leading DCS Vendors 

                                           Distributed  Controller System
                       If taken from a narrow point of view, maybe PLC and DCS are functionally the same. However, a lot of plant technicians and engineers are not aware of the other side of the debate, namely the engineering effort and the commercial ramifications. Of course, for huge plants with I/O's ranging from 10,000 to 30,000 I/O points, and beyond, it is silly to even think about PLC. From my experience, a DCS is not the same with PLC in the realm of huge systems such as oil and gas plants, as the following list will show:

1. A PLC is cost-effective up to a certain I/O count, and so is the DCS. But the difference is in their starting points: the PLC is cost-effective from 0 to a few thousand I/O points; the DCS becomes cost-effective starting from a few thousand points and beyond. 

2. A PLC becomes a subsystem of the DCS in rare occasions when the situation calls for it, i.e., purchase of huge package systems with engineering schedules incompatible with the DCS schedule (I/O lists cannot be submitted on time before the DCS hardware freeze date). Note that this package system is a process system using continuous control, not discrete. Based on this, a PLC can never be larger than a DCS in terms of I/O count.

3. In large plants the DCS is king because most owners want a single source of hardware support and service, and this mentality naturally denies the PLC a foothold. Package vendors are no longer required to provide PLC for their system. Everything is connected to the DCS.


SCADA: AS ALREADY EXPLAINED, IT NOTHING BUT A SOFTWARE USED 
TO GATHER DATA FROM THE FIELDS INSTRUMENTS WITH THE HELP OF
YOUR DCS OR PLC DEPENDING ON THE APPLICATION VIA THE SERVER
AND MAKING IT AVAILABLE IN AN ANIMATED FORM. THIS IS
USUALLY FOUND IN YOUR CONTROL ROOMS AND DEVELOPMENT ROOM


                                                                            SCADA
SCADA is the Software tool in which you can able to view/Monitor/Control your Process Variable data and Graphical representation of your plant etc...It's an operator front end display Example of few SCADA S/W is Wonderware, IFix, RS View, WinCC etc
SCADA is Supervisory Control and Data Aquisition which is used to control and Monitor small number of Equipments in a field.SCADA systems are typically used to perform data collection and control at the supervisory level. Some systems are called SCADA despite only performing data acquisition and not control.The supervisory control system is a system that is placed on top of a real-time control system to control a process that is external to the 

SCADA system (i.e. a computer, by itself, is not a SCADA system even though it controls its own power consumption and cooling). This implies that the system is not critical to control the process in real time, as there is a separate or integrated real-time automated control system that can respond quickly enough to compensate for process changes within the time constants of the process 

SCADA is the Software tool in which you can able to
view/Monitor/Control your Process Variable data and
Graphical representation of your plant etc...
It's an operator front end display
Example of few SCADA S/W is Wonderware, IFix, RS View,
WinCC etc 


IN SHORT!

PLC:

  • in manufacturing processes(for production of things)
  • for simple batch control 
  • intensive logic controls
  • can handle a no. of I/O s at a time
  • downtime => lost production
  • usually,no need of redundancy 
  • fast logic scan(=reading I/Ps executing instructions and providing O/Ps)
  • compact
  • easily customised 
  • for smaller applications

DCS:
  • in process control (for production of stuff) 
  • for complex batch control
  • advanced analog loop controls
  • downtime=>lost production+damage to process equipment+ may lead to dangerous conditions
  • so Redundancy must
  • large in size
  • cant be easily customised
  • for larger applications and plant-wide
In detail

What are you manufacturing??

PLC:for simple batch control i.e.,manufacturing a batch of goods(things)
Eg.,in bottling plants
DCS:for complex batch process i.e.,producing a product by transmission from raw materials(producing stuff)
Eg.,in oil refining plants,in steel making 
Specific to type of control
PLC: very logic control intensive.Can handle a no. of digital and analog I/O's at a time.
DCS: Regulatory/Analog loop control.It also provides ratio/cascade/model-predictive /feed forward control

Effect of downtime
What is downtime?

It is the time that the process takes to come to normal operation after a catastrophic failure.
PLC: Downtime results in only lost production and does not typically damage the process conditions or equipment.
For eg.,if there is some problem in the manufacturing process of a bottling plant, even if the process is stopped for a while, resuming the process back to its normal operation is simple and not time tacking. providing redundancy will be costlier than handling the downtime expenses so generally redundancy is not provided by this.
DCS: Downtime results not only in lost production but also leads to dangerous conditions or damages the process line and resuming the process is expensive and difficult too.
For eg.,In steel making process if the process stops abruptly and the pipelines with process fluid contents may freeze and damage the pipelines this would lead to more expenses.

Degree of customisation
PLC:It delivers a tool-kit of functions and building blocks that can be easily customized.So it can be used for varied applications by programming it according to the application.
DCS: Its highest priority is high reliability so standard functions are baked in to provide a complete solution to a particular application. So it can't accept many custom modifications.

Up-front cost
PLC: in $$
DCS: in $$$$ ;However its superior to PLC in operation and proprietary in general.
Size
PLC: compact
DCS: large
Replacement
PLC: replaced the conventional relays
DCS: replaced the pneumatic & single loop controllers


DCS is Distributed Control Systems which is used to control very big plants by using simple GUI screens.PLCs are interfaced with DCS for interlocking.