Please Help Using One Shots

[Lancie1]

Thanks, Genius. You made some wise comments there. If only we could pour your lessons into all the student's heads without causing them to get upset!

 

[bryan372002]

Once again i thank any of you guys that have constructive criticism

and yes I completely understand that a wrong program can Kill.
but fortunately I'm not that far along yet....lol

Yes I am very serious about learning this.

And I never wanted the complete assignment done for me, what I wanted was some direction in making the step that I had highlighted function.

What i want is to do the work and have someone tell me where i went wrong.

No I'm not a rude student and I have great respect for You guys that have been doing this for a long time, but on the flip side I belive in treating other with respect when i'm treated with respect, I want very much to learn this valuable trade and I will learn it

 

[geniusintraining]

Have a sense of humor (if you can’t laugh (especially at yourself) then you will hate this job)) sometimes this can be our only sanity, we all live on the edge.

How come you guys can't spell a simple little word like humour?? I've noticed it with colour too, but was too polite to ask.

oh ya one more...you can make fun of the boy's on the other side of the pond...their programmed that way

 

[Terry Woods]

Steve...

Regarding your questions...

"Who calls inputs "Lights"?
Why are we using LogixPro simulator when we are referring to AD outputs (Y0) in the spec?"

Yeah... it sounds kinda weird... almost like one PLC communicating with another through indicator lights and photo-detectors... but then, an input by any other name is, after all... just an input. Maybe it is indeed a case of photo-detectors looking at indicator lights!

However, I would NEVER name inputs in that manner! I would name the input in terms of what the light being ON really means! But then again, this is a new guy that is just breaking in and needs to develop an understanding of how this stuff works while using the most basic concepts (as in, an input is an input).

As far as outputs, well... you can "name" them anything you want, can't you.

By the way... Yxxx also applies to TI.

But, on the whole... yes indeed, it does look like a weird spec.

 

[Lancie1]

What i want is to do the work and have someone tell me where i went wrong.

Okay, fair enough. You went wrong by pulling out PART of the whole, and expected it would work as a stand-alone unit. Maybe, maybe not. In this case Step 4 was still pretty much the same, but why put us through the hassle?

Only the small clues in the description will allow it to be solved. That means having both parts of the problem so that the differences can be noted. The fact that In Part 1, Step 4 is described differently than in Part 2, Step 4 is a big help in figuring out just what is needed.

In Part 2 (Step 7), all steps except number 4 are pretty much "reversed" by simply inserting a bit to keep the output off. Step 4 is different because in both Part 1 and Part 2, it consists of TWO branches, one to turn on the output Y1, and a second branch that again does TWO functions: Latch in Y1, but then turn it off at the right time.

Now, zip your program and post it and we will tear it apart piece by piece!:site:

 

[Terry Woods]

It's obvious that Bryan has never heard of, and possibly will never appreciate the worth of, the "School of Hard Knocks".

We won't KILL you. But... we WILL push you to your limits!

Why? Why would we do that?

If you have to ask that question, then perhaps a better question for yourself would be... "What am I doing? Why am I trying to get into this field?"

GET SOME SKIN!

 

[bryan372002]

well this new guy didnt write the specs, so i never called them lights even tho that is what i was reading.


oh and i do have skin. thick skin! But i'm also a firm believer in politeness.

and if I or my questions ever become a hassle, then dont bother to reply

 

[Terry Woods]

So... are you saying that a Spade ain't necessarily a Spade? And you don't recognize a Spade when you see one?

 

[rsdoran]

In all fairness, I may have a slight advantage because I have taught this PLC Programming course to students once upon a time.

So you wrote when light 1 is on etc?

I do not have to be offended and not worried much if I offend(ed) anyone at this point. My whole point was you were taking inconsistent statements and stating for a FACT that you knew the answer.

Guess what, you did not.

I also do not belive the examples you provided where these ckts may be used were proper either but I will not debate that.

 

[bryan372002]

yeah i recognize a spade about as well as i recognize feeling like i walked into a pit of rattle snakes

 

[rsdoran]

yeah i recognize a spade about as well as i recognize feeling like i walked into a pit of rattle snakes

Not rattle, VIPERS. All Terry or I wanted was you too state, without inconsistences, what the assignment was, then it may have been possible to discuss it and help you through it.

As it is there are now 5 pages on this thread without much to help you to understand what was done, except now you have the answer to your assignment.

Is that what you wanted?

As an addendum, Lancie I never stated your logic was wrong, just what you interpreted was needed as logic.

 

[bryan372002]

No that is not what I wanted and if you go back to page one you will see that is not what i wanted from day one. what i originally aSKED FOR WAS HELP In SOLVING STEP 4 OF THE SECOND PART. and I have gotten everything but that.except from a couple of members that have seemed to be truely helpful.
the truth of the whole matter is that the specs were not very specific but regardless what i originally asked for guidance in was

"when lights 1 and 2 are turned on y1 will be off and remain off until light 3 was turned on, y1 will remain on after light 3 is turned off as long as lights 1 and 2 are on

and the reason we are using logix pro simulator when the spec were written using Da (Y1) is beacuse I have logix pro software and not direct logix, but all the same a program is a program

 

[rsdoran]

No that is not what I wanted and if you go back to page one you will see that is not what i wanted from day one. what i originally aSKED FOR WAS HELP In SOLVING STEP 4 OF THE SECOND PART. and I have gotten everything but that.except from a couple of members that have seemed to be truely helpful.
the truth of the whole matter is that the specs were not very specific but regardless what i originally asked for guidance in was

"when lights 1 and 2 are turned on y1 will be off and remain off until light 3 was turned on, y1 will remain on after light 3 is turned off as long as lights 1 and 2 are on

and the reason we are using logix pro simulator when the spec were written using Da (Y1) is beacuse I have logix pro software and not direct logix, but all the same a program is a program

You have been offended, not much I can do about that, but I never tried to offend you at any time. I was just attempting to get the facts stated properly.

For most of this thread I had no idea you wanted help on PART 4, why you ask? I never saw a PART 4 mentioned, what PART 1,2, and 3 were, what you had already done or specs to show what was actually needed. Did you really expect people to take a piece and make a whole.

For "when lights 1 and 2 are turned on y1 will be off and remain off until light 3 was turned on, y1 will remain on after light 3 is turned off as long as lights 1 and 2 are on

Alaric posted an answer to that here: http://www.plctalk.net/qanda/showpost.php?p=173255&postcount=6

I can see it will not matter what is said now, hey Terry can I get hit off that....

 

[Lancie1]

Bryan,

You may find that it is almost impossible to accurately describe the process of "How to read a word description and convert it to ladder logic". The short answer is "I did it in my head, using 30+ years of accumulated experience". How does that help you?

It might help to understand the basic parts of a ladder rung, as follows:

|            INPUT SECTION                  OUTPUT SECTION | 

| STOP SECTION        START SECTION                        | 

|----||---|\|------+-------||--------+------------( )------|

|                  |     start 2     |                     |

|                  +-------||--------+                     |

|                  |                 |                     |

|                  |    SEAL-IN      |                     |

|                  +-------||--------+                     |

There are some shortcuts and aids, such as Karnaugh Maps and State Tables, but you do not know those yet, nor even enough to understand that I and several others, such as Alaric, have described parts of the process several times, in different places, but you must have missed it. Apparently your impression of how to get from words to logic is not very clear.

Okay, here is another try at describing the process.

"when lights 1 and 2 are turned on Y1 will be off.." means that AT THIS STAGE OF THE PROCESS, Lights 1 and 2 have no effect on Y1. They WILL NOT turn it on. "Lights 1 AND 2" means that these two INPUTS are ANDed together, in other words, joined in series ---||----||--- like this. Because these two inputs in series must not turn on Y1, we know right away that there must be another inhibit contact (a normally open contact from the Y1 output as Genius explained at least once) that will keep Y1 off until the next step.

"and remain off until light 3 was turned on,.." means that when Light 3 is ON, then Y1 must go ON. Converting this little part to ladder logicand including the REverse Switch, results in merely |--||--||----( )--|

"Y1 will remain on after light 3 is turned off.." means that AT THIS STAGE, Y1 is latched (or sealed in) so that turning off the thing that turned it on in the first place will have no effect. If you do much PLC Programming, you will need to learn about seal-ins and where to use them. You will see this subject again and again, unless you drop out.

"...as long as lights 1 and 2 are on" means that (after Light 3 is off, Y1 stays on until Light 1 OR Light 2 is turned off. Then Y1 also goes off. Again, there is AND in between, so we know that these two Inputs muste be Boolean ANDed (in series. If it said Light 1 OR Light 2, then we would OR them together (put in parallel). Converting this results in |---||---||----||---||---( )--|.


Questions?

 

[geniusintraining]

Hurricane is a come-in



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