Architecture of PLC

Hi everybody in last post i told about Basics of PLC. Now i get you into Architecture of PLC. Below you can see the general architecture of PLC.

 First we can see about CPU in PLC.

a. CPU(Central Processing Unit) :-

                               CPU is nothing but a microcontroller. It is very important to a PLC controller. PLC is a industrial microcontroller system. Now we are using 16 bit or 32 bit microcontroller in PLC. CPU performs more number of actions listed below.

1. Communication

2. Interconnectedness among other parts in PLC

3. Program execution.

4. Memory operation

5. Overseeing input & setting up output.

From the beginning CPU performs more number of memory checkups to reduce errors.

Basics on PLC

PLC (Programmable Logic Controller) is defined as digital computer used for automation of electromechanical process like relay operations. Below you can see the relay operations.

Now, imagine that someone wants to control a 220Volts 1 K-Watt load with a command that comes from a 5 Volts battery. A load-Relay should be used for this application. The Coil of the relay is driven with the 5 Volts. The contacts from this relay (NO) will be connected in series with the power supply of the load. Thus, the load will only operate when the relay is actuated. Our friend bellow will turn on an electric oven bare-handed!!!

Programmable Logic Controller means we can control the process in industries by programming through PLC. For ex : In power plant industry, if we need to control the flow of steam to produce electricity or control some other parameters in industries just create the logic of the controlling process then program in PLC. we can easily control the whole process without any disturbances. Later we will discuss about the programming in PLC.

Why we need PLC?

Generally most industries having repeated process or controlling the parameters in certain conditions. For these purpose we can't accurately finish the work by manually. Now a days automation is heart of the industries. Main aim of the automation is to reduce the manual work, increase accuracy, increase productivity, etc. These task can't be achieved by manually. In olden days relay logic system is used for automation.

Relay logic system is like a switch. Normal relay is used for automation. I will explain the process how they are used the relay logic system in automation in industries.

Relay logic system is hard wired connections not programmable. I shown below image is one type automation process. There are two switched stop and start and one output CR1 that output is given to the first relay which is normally opened. Same output is given to second relay which is normally closed. Now do the process. Stop switch is normally closed. If i press start switch CR1 output get energized then both relays first goes to on position and second goes to off position. So G output is energized.

If i pressed stop button same process is done but first relay goes to off position and second relay goes to on position so R output is energized. Below diagram is simple automated logic. These connections are hard wired in Relay Logic System it is not programmable. So if any problem occur we need to rewire it. So it is more complex and time consuming.

We have lot of disadvantages in Relay Logic System. Using this same principle PLC is developed with lot of advantages. Same switch concept is applied in PLC using solid state devices. Above example can applied in PLC also. In PLC using digital computer program the logic through corresponding software we can easily program and execute it. Later we will discuss about programming software, etc.

Disadvantages in Relay Logic System :
 1. All connections are hard wired so complex logic connections create confusion.
 2. High power consumption. 
 3. Large Size.
 4. We need one electrician for troubleshooting purpose.
 5. High Maintenance.

Advantages in PLC :
  1. All the logic is programmable so complex logic also easy to access.
  2. Low power Consumption.
  3. Miniaturization.
  4. Less maintenance.
  5. In single PLC we can made lot of input and output connections.
  6. very fast.
  7. using single PLC we can control whole process.


I hope now you have basic knowledge in PLC. In next post i gave very interesting concept in PLC. Please read that. If you like give your comments.

Work Bench

This post is for my electronic friends. because this is an electronic circuit stimulation software. Its very superb and marvelous software in my point of view. Its very easy to construct circuit and we dont want invest something to do some small circuits. This software is enough for that.
If you need that software download it here.

TeamViewer Software

One day i need to communicate with my friend through internet which is not with my network. I found the software team viewer. its very interesting. Its very simple to use also. Just open the software and generate the code for you host (computer). Get the team viewer generated password which host you want to connect. then paste then code and click connect. But its only one way communication.

Above i taken the screenshot of the software.You can view very clearly. Rightside you can see two box ID and password. thats for you host. and left side one box thats for you need to paste the ID of which host you need to connect.

If you need that software download it.

NDCR

This is for my electronics and physics friends,
I developed a small tool for calculating resistor values either by giving values through color or based on bands.
Iam trying to improve this tool with your valuable feedback.

Download Links :http://hotfile.com/dl/75782203/9051059/ndcr.exe.html




NDCR : New Dimension of Calculating Resistors.

Pre-requirements:

1. Browser (eg:- Internet Explorer or Firefox).
2. JRE. (Java Runtime Environment).

Already many tools are available for calculating resistor values but this tool is my contribution.

If you don't have JRE installed in your machine, please download it.

LIGHT

 LIGHT

Some body think light is a simple concept. what  special in this?

But all can't know this.

In this article i will explain very simply like to teach to child's.

Lets come to the concept. Photon is the quantum particle of light. Quantum particle means very smallest particle.

Naturally Photon in wave nature. 

Where is the Light come from?

How it can travel at high speed?

I will explain it detailly. Light is emitted from the electron. How?

In normal condition it will not emit anything. if we applied some energy means it will emit.

we all know in an atom electron revolve the nucleus. If we apply energy to the valence electron(electron's in last orbit) it jump from lower energy state to higher energy state.

Whats is lower energy state and higher energy state?

Normally every orbit has its own energy. In the last orbit also has some energy but low as compare to first orbit. So we need to apply only less amount of energy to jump electron to higher energy state and as quickly it returns to original position. When it return to original position it emits the supplied energy.

 Now i hope you clear about how energy is transferring from electron.
Electron emits that energy in terms of photon. i already told combination of photon is a light.

then You have another question.

All the atoms has electrons then why light doesn't emit from that atoms like copper, zinc, etc.?
Why it emits only from some kind atoms like sodium, tungsten, etc.?

 That's the good question.

What i told is right. All the atoms are emitting  photons. But we can't see.Why?

Light depends on Energy of emitted photon. For each and every atom has different no.of electrons and different energies. So depends on that i will emits the photons.

I think  you confused.

If we applied the force on the atom the electron goes to higher energy states. then it emits photon.
for example

daily in our life We are using tungsten lamp. In that when we switch ON suddenly it doesnt emit photon. Initially it get heated. Initially thats mean applied energy(electric power) is low so it getting heat if we applying energy continuously it getting more heated and goes to reddish color. if the applied energy goes over the limits means after wards only electrons starts to emit photon(like visible light).

Before electron emit photon in visible range. it emits photon but with lower energy so cant see that it is in like infrared light spectrum. 


All the atoms are emitting photons but depend on the energy light is produced in different range.


if we applied more amount of energy means electrons jumps to very higher energy states and it gets more vibrating so the frequency of emitted photon also high. According to the electromagnetic spectrum we can find which type of light range in emitted from the electron.


Now i hope all are clear about the concept of LIGHT.

Einstein Energy Equation

EINSTEIN ENERGY EQUATION

we all know, Einstein energy equation is very popular and apply for all extreme.

Some of them knows about that equation but what's the real concept behind.

now i will explain briefly about energy equation E=MC^2.

we all know,
E = ENERGY
M = MASS
C = SPEED OF LIGHT.

what's the main concept of this equation is to find the energy of an object or mass?

definition of this equation is :

"multiply the mass of the object by twice the time of speed of light."

speed of light is approximately 3*10^8.

why Einstein take these quantities to find the energy of an equation?

this is the main part of this article. watch carefully


what i researched about this concept is :


if we want to the find energy of an mass means first we need to know energy of an single electron. then only we can find energy for whole mass.

why we need to find energy for single electrons means, atom is the very very small particle in the mass. so if we find the energy of a small mass means we can multiply to mass of an object.

now you have one question,
why einstein take the speed of light in the energy equation?
its the good question. here only the einstein proves his stuff.

why he take speed of light means?

we all know in our knowledge light only can travel maximum speed in the universe.
if a particle can travel at high speed means it has large amount of energy.

i think you confused in this matter.
lets i explain with an example.

you can take our body as an example. if we have lot of energy means we can do lot of works and less amount energy means we can't do much works. our body also depends on energy. if you confused means take a ball it can travel at the speed depends on force we applied and energy in the ball. if we applied more force, energy of an ball is low means it will damage else it travel at high speed.

Now we all clear on if a object travel at a speed depends on the energy of the object.

By this concept only einstein found energy of a single electron. how?

we all know light is emitted from the electron, i already said if a object has more energy means it can do more works. if light can travel at very high speed means electron has large amount of energy. energy of an electron is directly proportional to the speed of the light.

we know speed of light so easily we can find out the energy of a single electron. then multiply the speed of light to the mass of the object. why we want to multiply means we only found the energy of single atom so we need to find energy of whole mass.

Then you can have another question why einstein multiply twice the speed of light?

this question is raise for me also, then only studied if we focused to a single electron, it will emit twice photon.

that means exciting wavelength is shorter than the emission wavelength.


so now i believe you all clear about the concept of energy equation.

thank you for all visiting this article.