central processing unit

im trying to figure out if the central processing unit does one of four things?

1 looks at the inputs, makes the decision provided by the program and sets the outputs

2 looks at the outputs makes the decision provided by the program and sets the inputs

3 serves only to store the program in memory

4 understands only ladder logic

pls if u know help me

hnc87

hnc87 said:

im trying to figure out if the central processing unit does one of four things?

1 looks at the inputs, makes the decision provided by the program and sets the outputs

2 looks at the outputs makes the decision provided by the program and sets the inputs

3 serves only to store the program in memory

4 understands only ladder logic

pls if u know help me

hnc87

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Is this a multiple choice question on your homework?

yes it is i havent gotten the book yet but my teacher let me borrow his activities manual so i cant look up the answers and i wont beable to buy the book till friday

The answer is 1.

Here on the Forum, we appreciate the effort that it takes to employ proper capitalization, punctuation, grammar, and spelling. Even simple homework questions get a great deal more attention when your effort in research and in presentation are apparent.

Thank You for all your help. I will take in note of what you have said.
hnc87

I sympathize with you - when I was in college I was always dead broke, and I would wait until a week into classes before deciding to buy the books. Quite often I got by just fine with notes taken in class and an occasional study group. Other times it was obvious that without the book I couldn't get through the material either because the professor's lecture stunk or the material was too complex.

This looks like a class where you will need to get the books.

I believe this exact topic was covered yesterday. We will help you if you are willing to help yourself. Do a little research on the internet and I believe you will find your answer quickly. I don't mean to be rude, we just want to see a little effort on your side.

things they don’t teach you in college ...

this brings up a memory from days gone by ... here’s a “trick” to buying college books that might help ...



if you know that you’ll be taking “Basket Weaving 101” next semester, stand in the hallway just outside the Basket Weaving classroom as it’s letting out for the last time ... wave some cash around and say “need-a-book need-a-book need-a-book” ... chances are a student will sell theirs to you -



for MORE than the campus book store will pay them for it - but for MUCH LESS than the bookstore would resell it to you ... (of course you’ll want to find out the going rates - and book versions required, etc. - before you start to wheel-and-deal) ...



everybody wins this way - except the bookstore - and who cares about those bloodsuckers? ...



so you save money and use the book all semester ... life is lovely ... and then ...



the day the NEXT semester starts, you stand in the hallway just outside the Basket Weaving classroom as it’s meeting for the first time ... wave the book around and say “buy-a-book buy-a-book buy-a-book” ... chances are a student will buy yours from you -



for LESS than the campus book store will sell one to them - but for MUCH MORE than the bookstore would pay you for it ...



once again, everybody that we care about wins ...



this trick saved me literally hundreds of dollars - and a lot of time standing in line at the bookstore ...

if you know that you’ll be taking “Basket Weaving 101” next semester, stand in the hallway just outside the Basket Weaving classroom as it’s letting out for the last time ... wave some cash around and say “need-a-book need-a-book need-a-book” ... chances are a student will sell theirs to you -

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Not a bad idea but a little risky... what if the professor decides to change textbooks (or even just update to a newer revision) between semesters? It's happened to me before and you're left with an expensive paperweight. Of course there aren't a lot of alternatives for the student... the used book buyback system run by the campus bookstore is always an absolute racket.

yep, you take your chances - and I got stung once or twice ... but even so, everything considered I still came out way on top in the long run ... like you said:

the used book buyback system run by the campus bookstore is always an absolute racket.

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I knew one guy who actually made some decent extra money doing this ... he'd buy more books in the hallway than he needed - and then sell them in the hallway to incoming students ... sort of like a black-market bookstore ... he was the dude who steered me on to the idea in the first place ... I saw him lugging a stack of psychology books around one day and asked him what was going on ...

Brand new book for the Fall semester, 140 dollars. The bookstore then buys it back, in near perfect condition for 15 bucks, all because "We only offer that calss in the fall, next semester is spring, so we can't sell it!"

Ha, completely bogus. They hold onto it for 3 months and sell it for for 120 dollars "Used".

Scam artists...



On a side note, I still have all my old Circuits and PLC books from college. They come in handy every once in a while. I lent one out to a coworker who needed to learn the basics of AB PLCs (XIC, XIO, OTE, OTU, OTL, etc.)

Brand new book for the Fall semester, 140 dollars. The bookstore then buys it back, in near perfect condition for 15 bucks, all because "We only offer that calss in the fall, next semester is spring, so we can't sell it!"

Ha, completely bogus. They hold onto it for 3 months and sell it for for 120 dollars "Used".

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You could also wait for the end of the next semester then sell it, if they are going to use it in following semester they usually will offer you at least half of what its worth.

Another option is to buy an "international" copy on the internet. These are usually books that are copy righted brought to another country, photocopied, and put back together without the original copy right.

I bought a semi-conductor book like this online, the book at the book store was about $130, including shipping I payed $15. The book was identical, even the same version, the only difference was it was a soft cover and had no copy right information.

obviously you will not be able to sell it back to anyone but another student.

2 Looks at the outputs, makes the decision provided by the program, and sets the inputs

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If will help in your PLC training if you learn this one early. Anytime you see a line that says "...looks at the Outputs and sets the Inputs", please learn that this is a trick answer. Reality is the opposite -- a PLC looks at the Inputs, and sets the Outputs!

this brings up a memory from days gone by ... here’s a “trick” to buying college books that might help ...

Click to expand...

The old college textbook hassle carries me back about 50 years...I had forgotten about that. Old times, old memories, some bad, but mostly good...

I could never seem to win at that game, no matter what I tried. I remember one quarter when I attempted to beat the system. That university was on the 4-quarters-a-year system back then, instead of semesters. As usual, my Co-op job and part-time job on the university ag campus chicken farm only paid enough to scrape by. I decided to buy all my engineering books from friends and acquaintances that had the courses earlier. I think only one of about 6 books that I bought like that turned out to be the correct book. Either it was an "obsolete" edition without the same homework problems, or the instructor did not use the official book because he was writing his own textbook (and using the class as free proofreaders and checkers), or the university had changed publishers between quarters.

The times I "bit the bullet" and bought at one of the campus bookstores, many of those books would be declared obsolete at the end of the course, because a different publisher's book was going to be used by the next professor to teach the course.

I never got to keep the books that I could sell back, because I always needed the money to buy the next batch. Even the last batch that I had when I graduated, I had to sell to get enough money to get out of town on the Greyhound bus. Ah, the old Greyhound...what young freshman in modern times would consider going off to college on the Greyhound (if you could find one), toting 3 suitcases containg all their possessions? And living underneath the football stadium because it was the cheapest housing on campus--$50 per quarter is what I remember?