Need to know about design of plc for sequential process control

[shirin]

I am in my final year of engineering and we are doing project on design of plc for sequential process control so i am not able to understand the project what we are told is plc is used to control different machines sequentially there are different blocks susch as microcontroller 89C52,power supply,uln2003an,relays and lcd so i need have the detailed explanation of all the above blocks......so please mail me the matter within 2 days.

[Fred Floggle]

Final year of "engineering" ? what you call engineering and I call engineering are obviously different.
You request is totally without structure or meaning , and why the hell should I do anything within two days ? Try learning some manners and be grateful for what you receive whenever you receive it.

[Fritz_frederix]

Fred,

You're absolutely right, we're on the helping site. All what we are trying to do helping people in a friendly manner NOT in a forced manner.

Shirin,

You need not only to learn alot about engineering but even a lot more on the social part

Rudi

[Fred Floggle]

Hi Rudi ,
I was perhaps a bit hard , but there are two reasons , the first being that his attitude is a bit poopy , the second is that I plugged my little 150W water jug in this morning intending to make a nice cup of tea , went to the machine I am commissioning to be met by a barrage of silly bloody questions , picked up the laptop to do a couple of program changes , returned to the office three hours later to find the kettle thermoplastically welded to the top of a desk , and yes I know I should have bought one that cost more than $1 .
There seems to be a certain connexion between some flags and arogance , but perhaps this is again unfair.

[Fritz_frederix]

Fred,

Only thing I can say is look at the bright side, this evening the weekend starts.

Cheers

[anbu]

forget it men ...
still he is immatured..he's doin final year B.tech afterall..

[Fred Floggle]

There is a phrase that maybe you have heard - old enough to bleed , old enough to be butchered .

There are a couple of alternative meanings to this - but I am sure you know what I mean . I will give him the same compassion as his kinsfolk give me every day :-**** all . There is a time for some people to learn basic manners , and cometh the man , cometh the time
There is a certain breed of person who think they have a God ( or perhaps Gods) given right to demand and be served - they are mistaken .
This site is for people who wish to learn and have genuine enquiries - I don't care if someone asks me the most simple question if they have explored themselves - it will be my pleasure to oblige , but I abhor this rudeness
By the way , you surely don't regard BTEC as engineering do you ?

[Lancie1]

shirin,

Okay, your 2 days are not up...yet!

Here is explanation of those "blocks" that you asked for.

1. Microcontroller 89C52. This is the microprocessor "brain" that controls all other devices.

2. Power Supply. This provides power transformation form the incoming supply voltage down to the voltage needed by the PLC and perhaps other devices.

3.uln2003an. Who knows what this could be? Perhaps it is a type of Input/Output module for the above microcontroller?

4. Relays. These are used as interface devices between the PLC and field devices that either are not compatible with the PLC output voltage, or use too much power to be controlled directly by the PLC

5. LCD. This is an operator display screen that is used as an interface device between the human operator and the PLC. It can be used to enter Start/Stop commands, enter numerical values,display text, and some have built-in LED lamps that can be programmed to go on/off as the PLC turns bits on or off.

[CaseyK]

Today I interviewed for a Electrical Engineer position. After some chit chat, I was taken down to the shop "for a little test".

Test 1). Power supply, light, relay, NO pushbutton, NC pushbutton. Wire up simple circuit, like a motor control or MCR, so light will operate.

Test 2A). Same equipment as above, but substitute PLC for relay, ON to I00, Off to I01.

Test 2B). Draw ladder logic for above.

Last time, 2 of 17 passed Test 1 as 2A. Most fairly recent grads, applying for tech position. Even engineers were having trouble with it.

"Ladder Logic" (2B) got everyone.

What are they teaching these kids? OK, I remember, I have a bachelor of EUCHRE Degree.

BTW - I DID pass all three parts!

regards.....casey

[Eric Nelson]

Hey Casey, did you include "PLCS.net" in your list of 'references' on the application?...

beerchug

-Eric

[Fred Floggle]

Final year of "engineering" and he doesn't know what these things are for ?
Do you think it is fair to unleash him on the public ? My daughter is five and I believe she has more engineering brain than this.
This is simple stuff , surely you don't need to be taught it.
From experience , he will get taken on by a big european company , they will find out he is useless , and because they can't sack him , they will make him team leader and I will end up working under him. Please save me !
Before you say this doesn't happen , it does , a VERY large international tobacco company had a couple of clowns like this , and for whatever reason they progressed up the ladder of complacency , to the point where they became real dangerous . The company realised and sent them to the jungle where they figured they couldn't do to much damage (they couldn't sack them for obvious reasons)
They could do damage in the jungle , there was a rumble in the jungle , and many local people are still picking bits of boiler shell out of their roofs .
I beg again -Please Save Me !

[jstolaruk]

Ever hear the saying "The incompetent are promoted out of harm's way"?

[LadderLogic]

Wow, dude...

I've noticed what appears to be "an attitude", but I always thought that to be a product of less than perfect language skills. At least I would like to accept it as that.

On the other hand, there is a lot of people on this forum, for whom English is not the first language and who are far from being perfect using it (myself included). Nevertheless, no trace of the attitude there. Even if one considers the scope of locations and different cultures involved.

Mind-boggling.

[CaseyK]

ERIC:

NO APPLICATION! I have noticed over the years that on "permanent" and contract jobs, quite often there is no application, or not until after you are hired. I have gone into a few places to talk to management about doing some extremely short term programming or drafting, and spent an hour or two filling out an app that really says nothing, at least nothing relevant to the present time. Really now, does it matter what kindergarden I went to? What was my course of study in grade school?

I have found when you are told to come in early for an application, the places are extremely rigid, and undesirable.

I went to the locomotive plant on a resume only, not even a phone interview. Went for 2-1/2 months of projects, left after two years for "double" the salary on a short project. Just missed a huge layoff doing that.

I was once told by another contractor "You are no better then you last project". So true! You can have twenty years of AB experience, spent two weeks programming a GE, and be told by a HR person, well, you don't have recent AB experience.

Last year I spent over 1,500 hours on plc programming and design on my major project, alone. Since 1988, I can't imagine the total hours, but there have been about 25 plc brands, and probably 10 or more HMI/MMI brands. Was told ten days ago by a prospective employer that I don't have very much PLC experience.
They also said they were a 5 million dollar company (actually 1.5) and the salary range was 50-70K, actually 30-40).

plcs.net MEMBERS are listed in the refferences.

plcs.net should also listed under education!

regards.....casey

[Fred Floggle]

Casey , please see your list of suggestions "progamming"
To "gam" is crude newcastle slang for a blow job , agreed , some of our buds might try to shag the odd plc , but it is more in the metaphorical rather than the biblical sense