Please Help Using One Shots

[Lancie1]

You guys are tough customers. I have had to learn to intrepret various dialects of imperfect English. Okay, I will play along. Everyone is so sure that my logic is flawed. Here are step-by-step pictures. Please show me which one disagrees with the word descriptions:

1. When Inputs 1 and 2 are on, then Output 1 wil be on...Yes!

..and remain on after Input 1 or Input 2 is turned off ...Yes!

The only way to turn Output 1 off is to turn Input 3 on....Yes!

If Inputs 1, 2, and 3 are all on, then Output 1 will be on....Yes!

Add a reverse switch. When it is true, the program will work as follows: When Inputs 1 and 2 are turned on, then Output 1 will be off...Yes!

...and remain off until Input 3 is made....Yes!

Output 1 will remain on after Input 3 is turned off....Yes!

...as long as Inputs 1 and 2 are on....Yes!

 

[Lancie1]

After that point things change. What gets me is you state you KNOW what is being said but also state things like "I can not help" or "Methinks we are being played with here."

Ron, I am sorry and I apologize for offending anyone here. However I do reserve the right to defend my logic when I am correct. I am sorry if everyone else thinks I am wrong. Do you realize how difficult it is to remain calm when your correct logic has been branded as wrong?

I mean that I can't help if Bryan insists on misinterpreting the problem. I do know what the problem as stated means. But I also know that I can't help as long as Bryan doesn't also understand the problem. He thinks he knows what it means, but at the same time admits to being a student and a beginning programmer. He has demonstrated with his program samples that he knows very little about ladder logic. Yet he does not believe the old faarts here that have been doing this for 30+ years.

Bryan, you can't have your cake and eat it at the same time. If you want help you have to accept the help and understand that the helper may know a little more than you. You also have to be responsible for giving correct information about the problem.

Just guessing based on circuits I have encountered, this could be the pressure switches for a couple of air compressors. The reverse switch is the alternator (periodically changes which compressor is the lead) that switches control from one set (Inputs 1&2) of pressure switches to the second set (Input 3). The output runs Compressor 1 if the Reverse switch is off or Compressor 2 if it is on.

Second guess would be level switches at two sewage treatment plant settling basins. When the first basin is full, the reversing switch changes control from Inputs 1&2 in Basin 1 over to Input 3 in Basin 2. The Output is a pump that empties the full basin.

Third guess...well, why go on. It could be for any of dozens of real-world control schemes.

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

 

[TimWilborne]

So much tension. How many more days till school is out

 

[Lancie1]

TW, a lot of PLC courses are finishing up this week. There should be a lull soon, but only after all the laggards have used up their late extensions.

 

[TimWilborne]

Just kidding of course, looks like summer break is over

 

[bryan372002]

Of Guys here is the specs for this project word for word right off the sheet.

But first let me say first, Im not trying to desquise anything from anyone and im not stupid enought to think that there wasnt a chance that my instructor would hang out at such a website.

and yes I did assume things in this project because there is holes in the specs that do not specifically state what the conditions are. and yes I did talk with the insturctor this past tuesday and verified what he wanted on the part that was giving me so much distress

and Yes I am stupid when it comes to programming, but not so stupid that I dont know when something isnt working as specified.

I always appreciate help from anyone for anything, but You guys all need to come down off Your High horses, and try and have a little patience with A "beginner" Because whether you choose to believe it or not you were all stupid when it comes to Programming When you first started, I apologize for Bothering you all with My petty begginer problems.

Here it is

Project One

1. When light one is on YO is True (directLogic output)
2. when light 3 and 1 is are on Y2 will be on
3. When all 3 lights are on Y3 will be on
4. When lights 1 and 2 are turned on Y1 will be on and remain on after either light 1 or 2 are turned off. The only way to turn Y1 off after it is on is to turn light 3 on. If Light 3 is on and light 1 and 2 are on Y1 will be on
5. If no lights are on Y5 will be on
6. Y4 will be on only if one or more lights are on
7. Add an additional switch to your program so that when X3 is true the above program will work in reverse

That is as follows

1. When light 1 is on Y0 is false
2. when light 3 and 1 are on Y2 will be off
3. when all three lights are on Y3 will be off
4. When lights 1 and 2 are turned on Y1 will be off and remain off until light 3 is turned on. Y1 will remain on after light 3 is turned off as long as lights 1 and 2 are on.
   
5. If no lights are on Y5 will be off
6. Y4 will be off if 2 or more lights are on
7. If you add an extra input to the circuit say X4 could you make all the outputs flash when x4 was true?

The highlighted part is what I originally asked help for

Thanks and I pity the next beginner that comes this way

 

[TimWilborne]

Brian. You are always going to have those who are impatient and dislike students. I am one of those when it comes to student coming asking for his homework to be done, are rude, or demanding.

You have been none of this. You have worked along with the users here and that is good. Keep it up and don't loose your cool. If users here do it then you can ignore them. If you do it you will probably be labeled one of those rude students.

As far as my post I was just trying to keep the thread light

Look forward to more threads from you
TW

 

[Lancie1]

Bryan,

Now you are getting there. Lesson 1 is to learn that you cannot cut a part from the middle of a logic description and expect to get logic that means anything. It all works together. When assembled, it is one complete program. Parts of it alone do not mean anything. Give me some time, and I will now give you the correct solution.

 

[Steve Bailey]

So,,,,

If that is an actual spec written by your instructor, you have a case for asking for your tuition money back.

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

 

[Terry Woods]

(Just prior to posting, I see that there are many posts since I started writing this... never the less, here it is.)

So Bryan...

Would you PLEASE, PLEASE, PLEASE post the correct spec?

If you really have the "gut" for this business, then you should know that, for serious programmers, leaving a problem hanging like this is almost intolerable!

So please... please post the full and correct spec.

Lancie said...

"Terry, I believe I said word descriptions. I meant as opposed to mathematical and Boolean logic descriptions. Those would be more precise, as an old K-map man like you should appreciate."

You originally said...

"What you are saying then is that the description can be intrepreted any way your instructor wants."

Where I come from... we tend to write specs in English, using normal vernacular. In general, we do NOT write process-specs in mathematical or boolean expressions. It would really be great to receive descriptions (specs) written in mathematical or Boolean expressions! However... I would also insist on a written description of the expectations!

After all... consider where the "specs" are coming from... I know what I know... but I have no idea what the spec-writer knows. That is why we deal with "descriptions" written in "English".

Earlier Lancie said...

"Terry and Ron, you are trying to read things into the problem that are not present. Part 2 does not say that Inputs 1 and 2 have to turn on Output 1. You are reading something in here that is not there. In Part 2, the problem only says that if Inputs 1 and 2 are on, the output is off. Period."

First... I never addressed the second part.

Second... Ron is correct in pointing out the... inconsistancies? It wasn't so much direct-contradictions as much as it was omissions... the omissions, or unanswered specs regarding particular input combinations.

But then... ALL OF THIS is nothing more than hot-wind... until Bryan posts the complete and correct spec.

As given, and simply because of the various interpretations, the spec is untenable... unless someone happens to luckout and "shotgun" a solution... despite the lousy description.

 

[Terry Woods]

Bryan said...

"Thanks and I pity the next beginner that comes this way"

Bryan...

If you are serious about getting into this field... you gotta know, YOU REALLY GOTTA KNOW, before you do so, that you are entering a field that can, quite literaly, really, and truely, KILL PEOPLE!

This field is NOT A GAME!!! A poor programmer can KILL PEOPLE!!!

Those of us here that DO TAKE THIS STUFF INCREDIBLY SERIOUSLY... want the new-guys to be just as serious!

That means, on your part, if you are called out for being wrong, incomplete, or anything but right on the mark... YOU have to be serious enough to BITE THAT BULLET and open yourself to criticism and any teachings from those that have been around the block more than a few times... certainly more times around the block than you have been.

 

[Terry Woods]

After reading the "complete" spec...

...I can only shake my head from left to right, and back again, repeatedly...

I see another wannabe, that, I hope to hell, ain't gonnabe... God! I hope he ain't gonnabe!

Oh, Jeezzz... don't you know... Bryan is gonna be the Traffic-Control Programmer in your neighborhood!

Yeah, Bryan! That is a HARD-SLAM on YOU!

Are you serious about this stuff, or what?

HINT: BITE THE BULLET and LEARN!

 

[Lancie1]

Bryan,

Here it is. I have tested it using Logixpro and it meets all 14 of the Project specifications. Please ask questions if you have any. I am always honored to help serious students.

Ironic, isn't it, that the Part 2 Step 4 is still exactly the same as I originally programmed (except for the X4 flasher which we did not know about before)?

 

[geniusintraining]

Bryan lesson 3 chapter 9….

To be a programmer..

1. Be strong enough to take **** from other programmers (don’t keep your emotions on your sleeve)
2. Fight your fight (look at Lancie’s post, he stands up for what he thinks/knows is correct)
3. 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.
4. Think out of the box (Peter N and Terry W, have made me think more in this past year and learn more then I have in the last 5)
5. Don’t under estimate yourself (I have done more (automation wise) in the past 2 years then I thought I would ever think of doing ( in part thanks to PLCS.net and the people here)))
6. Try and model your programming skills after "these guy’s" collectively, I try and read as many good threads that I can…you will find that just by looking at the "poster’s name" you will know if this is going to be a good Equipment thread, Programming thread or Life lesson thread, many start out one way but end another

My point is you seem to have the drive, lesson 1 & 2 you got, you may need to work on #3 a bit, then the rest will come in time

Remember enjoy

 

[PeterW]

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.