Parking Barrier

If anyone help me, I have to do a Ladder Program of a Parking Lot with a capacity of 20 cars. When a car drive in to the parking Lot a sensor (input1) lift a barrier and keep it up for 20 seconds and then takes its original position, when a car want to exit the parking, another sensor (input2) lift anopther barrier and keep it up too for 20 seconds. The important thing is when the capacity comes to 20 cars, the system must disabled.
Ok Thanx

Try THis

Sorry its in 3 parts having problems on my side

part 2

part 2

part 3

part 3

Congratulations mnehez, you've just saved jocks the trouble of having to do his own homework wherein he might actually learn something about RLL programming. When jocks gets a job, can he count on you to do his assignments for him?

jocks, how do you prevent the gate from coming down on top of a car that stops halfway into the car park? Fixing the damages caused by your automated system could wipe out your profits. Maybe you should consider hiring an attendant.

corected counter

I made a mistake on the last part "car counter"
this should correct it

Steve Bailey when i used to study VB6 programming the trainning was to use examples to do a project.In fact I had a software engineer teach me the same way. If you think I did his homework , I probably did. In case you didnt notice there are points of my program which refer him to lookin at the accumaltor of the counter and subtracting from it. Would he hace gotten this on his own? In time,yes. As far as yout disrespect... It wasnt appreciated. Have a wonderfful day.. Buy the way dont worry about the car being half way jocks, Hopefully it will be Steves.

Also

I can understand you being mad at me, Which, who cares. But how dare you include jocks in this, all he did was ask a question. I think you owe him an apology.

mnehez,

Suit yourself, do jocks' homework for him. At the end of the day, all he's learned is how to copy someone else's work. Is that a quality you look for when you're interviewing potential employees?

Personally, I prefer to let the students show a few signs of interest by explaining what they've tried that didn't quite work out the way they expected.

Fine

To a point perhaps I was a bit aggresive towards explaining how to do this problem. I on the other hand did not see any where saying this was homework despite the simplicity of the task.

AS far as interviewing employees, the first quality would be how well they work with others.
(Which is a very desirable trate in the real world and expected!)

As far as jocks he did show "intrest" by asking a question. I also get agravated when asked to "show" how somthing works ,only to get a blank stare when I lend them one of my books and tell them to read and answer my questions the next day.

Yes it is important for a student to make mistakes. However there is a frustration threshold that needs to be observed. Thats why i feel you still owe jocks an apology for you remarks,
"Fixing the damages caused by "your" automated system could wipe out "your" profits. Maybe you should consider hiring an attendant.".
jocks is not your student!! Totally uncalled for.

Now don't get mad at mnehez, Steve. He posted bad code. I count at least three mistakes (only one of which he caught, and even then didn't fix properly), so that jocks will get about a 'B' for the assignment. And that doesn't count the assumption that the program is in an AB PLC (the logic won't work in all brands - that's why, mnehez, we try to TEACH the kids to fish, rather than handing them a fish, as you did.)

And that's assuming that his teacher doesn't know about this site (which is pretty unlikely - we've been getting more and more posts from profs these days, not to mention all the unregistered lurkers).

Plagiarism, of course, gets an 'F'.

Good luck, jocks - you'll need it.

mnehez:
You need a couple of more months and posts on this forum before you start demanding apologies. It is your perogative whether you use this forum to support students homework, but I would say that this student had definitely not reached the frustration level. BTW, spell checkers are availaable for free anywhere on the net.

See notice for new posters

Steve:
(Big sigh...)I too agree with the obvious sloth from students who pose questions exactly as stated in their homework pages without any thought on their own. This has been the bane of this open forum and will still be in the future. Your stance has been supported over and over by the pillars of this forum.

Thank you

I am intrested in my other two mistakes. Please post. However That it is two that did not appreciate my posting I will no longer post such things. But that still does not change the fact that an apology to jocks is in order, he after all did nothing wrong.

It's still three mistakes.

And I frankly don't care whether you post homework answers or not. Nor does Steve, if your read his post carefully enough. I've often counceled students to beware of a ready answer, just because it's posted on the internet. And your flawed answer is proof.

I also feel that you are seeing an insult that was not intended. Steve pointed to a potential flaw in the logic, nothing more. It's no more insulting than the laws of physics. Just because I FEEL like a fool when I forget some scenario in my program doesn't mean that the gods are trying to make me look foolish.


The errors:
1) The I/O count is wrong. The assignment calls for 2 DIs and 2 DOs - you gave him a system with 6 DIs and 5 DOs.

2) The entry gate doesn't come down if the Gate Sensor is blocked. If car #21 come up to the gate while car #20 is going though, the gate will stay up for him, and he will be able to enter. 21 cars in the lot is a no-no.

3) Your SUBtraction block is 1 - ACC ==> ACC. Let's say ACC = 5. A car leaves (total = 4). 1 - 5 ==> -4 cars in the lot! 3 cars enter (total = 7). CTU(ACC) = -4 + 3 = -1. A car leaves (total = 6). ACC = 1 -(-1) = 2. And it just keeps getting worse.
The SUB should be ACC - 1 ==> ACC

Sorry to Allen

I feel Jocks was insulted for somthing that I did. Thank you for the "availaable" spell checker advice also.

The fustration level comes from wanting to know somthing and not getting the answers or getting an answer that ,well, like steve posted. He could have easily posted something constructive and possibly showed me up. If allen did check my work and there were mistakes then by all means tell me and jocks,let us learn.

Allen you have a nice sight,I didnt want to start any thing and apologize for going for a tit-to-tat, that was wrong.Your also right the logic would deffinetly not work in a GE funuc. But rather than trying to confuse jocks with a bunch of words he may/may not understand, I gave him a visual that he may percieve as he wished,a starting point.Then I get attacked with what I perceived as nothing but pure insult deriving from what I can only percieve as an disgrutled person. I mean really, do honstly thik that jocks couldnt learn somthing from my post?

Sorry to slander your sight with my arogence and pride. I should know better.

I think it is great that former students help the current students.

However, I don't feel that being too helpful is really helpful. It is good let students struggle with problems and give just the hints they need to figure things out on their own. One can tell by the questions the student ask when the student is ready for the next hint.

In reality there are those students that have the 'knack' and those that don't. To the 'knackless', the PLC course is just an obstacle to a grade. In the end, I don't think helping the 'knackless' will make any difference because they will find a job in another field.

For those that don't know about the knack.