help me please.

Dear Sir;

Iam studying about PLCs,please can you answer these questions?

1) What are the different mouduls of PLC system?

2) What is the fuction of each module?

3) What are the advatages of using PLC's over conventional methods?

4) Give three typical applications of PLC's.

5)Give four types of PLC's.


Thanks.

These sound like the exact questions off of a homework sheet.

So, time for you to do some research, and this site is an excellant place to do it!

By going to PLCS.net - Interactive Q & A > PLCS.net - Interactive Q & A > LIVE PLC Questions And Answers > section and going back through a lot of listings, or using the search link you can find most anything you need to know.

I also recommend to look in the "learn ploc's" link at the top of the page. In the "learn plcs" under "manufacture's links" is "links" that will take you to lots of manufactures. Automation Direct makes a huge catalog that has all kinds of programming info, which some people have learned programming by reading. Others to check are Entertron and Klockner-Moeller (now just Moeller) "easy" relay, where you can interact programming.

As far as question number three, I will give you a little help there.... You can replace to cabinets full of relays 4' wide by 6' high, with a plc in a 2' by 3' cabinet. Easier troubleshooting and maintenance. Less components. more versatility, easier to modify. etc. And lots more....

Look around some, and let us know if there is anything that you can't really can't figure out.

...casey

Regarding question 3: I think that by now PLCs are the conventional methods.

Steve: I have to agree with you that plc's are the conventional method now.

Hard to say how old that plc textbooks are in school. I looked at a couple from the library interloan system that weren't current by the what we in the industry are used to.

I still see a lot of projects where a micro or smart relay would be the best choice, but they use half a dozen relays do to budget restrictions or other capital equipment restrictions.

And in the case of the standby genertor industry, the basic OLD building block for engine control was 7 relays and a timer when I started in 1972, and that is still what a lot of customers want, because a mechanic can troubleshoot it. I have seen a lot of microprocessor controlled panels pulled of for a relay panel. Progress???

best regards.....casey

Hard to say how old that plc textbooks are in school. I looked at a couple from the library interloan system that weren't current by the what we in the industry are used to.

Click to expand...

A couple years ago we built CNC machine for a major university.
That time I realised how far this place was away from reality and industry needs.
Looks like they still trying to invent PLCs and use "C++" programs to control machines.

Looks like they still trying to invent PLCs and use "C++" programs to control machines.

Contr_Conn,

You make it sound like doing so is arcane or, at least, a step backwards.

If that is what you mean then I will dare to say that you haven't programmed a process using "C" or "C++".

I spent several years programming machines using "C" and more than several years programming PLC's with Ladder and STL. I can't hardly wait for PLC's to catch-up to the times and incorporate "C" or "C++" as a standard language.

Just as having a PLC replace a cabinet full of relays was a huge step forward, so too, having "C" and/or "C++" added to (if not replace) the list of available PLC programming languages would be a huge step forward.

Terry,
Take a look at Control Microsystems "SCADAPACK", they have just
what you are looking for along with ladder logic.

Mickey,

It looks like a new company with a "new" idea!

I can see that they allow C and C++ to run with one of the normal languages.

However, I can't tell if they allow the C/C++ program to run alone!

In any case, it is a move in the right direction. This brings developers and programmers closer to the beast (the processor).

Several PLC's have had the ability to include C/C++ for special purposes for a few years now. But the overall control scheme was still based on one of the normal PLC primary languages.

Terry,
I never programmed machines with "C" but did a lot of work with Pascal and Visual Basic.

I don't think "C" will replace ladder in the near future, but it is possible that someone will force A-B to add "C" language as "an option". Maybe in ver 43
And it will be used by just a 0.1% of customers.....

Terry Woods stated

I spent several years programming machines using "C" and more than several years programming PLC's with Ladder and STL. I can't hardly wait for PLC's to catch-up to the times and incorporate "C" or "C++" as a standard language.

Click to expand...

Omron did this sveral years ago. Describe a function and then write what you want in C. Not many people were interested. Don't think they sold many. Don't know if it is available anymore.

Interesting your comments about waiting for PLCs to catch up. Omron did it years ago and could not sell the things. No one wanted them in Ozz for sure.

Hello,

And it will be used by just a 0.1% of customers.....

Click to expand...

That's probably why (even) Siemens added VB in there new WinCC version (6.0). In the older version you needed to write your scipting in C.

Rudi