help for timer problem--noob

Good morning,
I am a junior high school student studying plc on my own to learn skills.

I, have a question regarding a problem with a simple circuit.

I am trying to make an on delay timer, and an off delay timer controlling the same output. In other words, I want switch 1 to turn on output light 1 after a 1 second delay. I also wish this light to be turned off after a delay of 1 second when turning switch 1 off.
This seemed easy at first, but I'm struggling.
Any help would be appreciated.

Thank You

How are you doing this?
In Function Block?
Ladder Logic?
Other?

What type of PLC or software are you using, if any?
Can you post what you have tried to do so far?

Thanks for the quick reply.

Ladder Logic
koyo PLC

I have tried succesfully to use both on delay and off delay timers, but i cannot get both to work on the same output.

Thanks
Chris

I have a few moments and will be glad to help you figure this out, but would like for you to do the leg work.

I am not familiar with Koyo but it should all be the same.

So rung # 1 you have your input (Switch) which will activate a on-delay timer.

Rung #2 the DN (Done)bit from this timer will activate your Output. (light)

So now a question for you: How would you now activate a off delay timer by using your output which would now be true?

"How would you now activate a off delay timer by using your output which would now be true?"

That is the meat of the problem. I want this to work continuously. IE. every time iI flip the switch i want it to turn on.


I have my program as you posted, that is, the on delay timer controls the output for the light.

[x1]------(timer1)

[timer1]----(y1)



im pretty sure i need an off delay timer as well, but when I put both timers under x1, the off delay timer immediately turns on the light. So I know they cant be on the same rung. I tried to put them on separate rungs, but am not making any progress. I know I need to activate an off delay timer. Do I need to condition my output for my light upon the state of both timers? Im getting confused.
thanks again
Chris

Got it!!!!

I used an on delay timer twice.. it seemed odd, but it does the trick!!!



[x1]------------------------------timer1
[/x1]-----------------------------timer2
[timer1]--------------------------set y1
[timer2]------------------------reset y1
end



Thanks again for your time.. your hint is what helped me... great question......see you guys next time im stumped!!!!!!!!!!!!!

No problem, I dont want to confuse you, and I do want to believe that you are a JR High Student doing this for fun.

But just in case you are a Collage Student trying to get someone to do his homework for him, I at least want you to do a little thinking.

So lets make sure your timers work like my timers.

The on delay timer starts timing when the input before it is True. (Correct)

The off delay timer starts timing when the input before it goes false. (correct)

So we now have an input (light switch) that goes true and starts timing a On Delay timer.

The done bit from on delay timer turns on the output.

We now want a off delay timer to be ready to turn on and seal in the output.

To keep from making more rungs than nessisary you could just extend a branch around the ouput and put your OFF DELAY TIMER on this branch.

Then make another branch extension around the Done bit from the ON Delay Timer that you used to turn on your output.
On this branch extension put a TIMER TIMING BIT from your OFF DELAY TIMER, this will seal in your output until the off delay timer is done timing.

You could also do this with latch and unlatch output instructions, but I am not familar with your plc so not sure what function it has.

Let me know if you follow what I am saying and see if you can figure it out.

If not I have this drawn up in ladder already and can post it for you to see.

Looks like you used a latching type of instruction after all.

Here is a JPEG of the ladder logic I was trying to lead you to.

Glad you got it in your own way though.

So what you did probably looks something like this.

Hopefully you can see it, my screen shots are very fuzzy.

Thanks again for all of the help. I am a twelve year old who has been studying this since Christmas, when my dad and I got a plc, some switches, lights, and a buzzer, wired them all together and started playing..

I have been searching online for projects to complete with our plc sim, but have found very few..
We did get a game-show circuit working where 3 players each have a button, are asked a question and the host controls right answer vs wrong answer. It has been fun.
I started the on off delay after my dad had me read about counters and timers. We are going to keep score on the gameshow project with a counter. I think we are going to add timers to it as well (5 seconds to answer before automatically being wrong) As a small project to see if i understood the concept of timers after my reading, he gave me the on off delay switch as a project.
Thanks again for the time and patience.
I'm sure I will be asking some more questions soon.

Chris

You ask away anytime.

I wish I would have started PLC when I was 12, I would be rich by now.

Another fun project to do when first starting is a traffic light.
Get some different colored lights and try to simulate a real traffic signal.

Good luck and keep up the good work, your are doing fine and will be well ahead of the curve.

Take Care.
BCS

Hey, thanks for the traffic light idea. I remember when Dad first introduced me to these controllers. He used a traffic light as an example. That would have seemed impossible two weeks ago, but I think I have a chance at being able to make it work!!!
Where would you look to learn more about these plcs at my age? My Dad said there might be some online courses, but I learn so much through youtube and personal instruction, that a course seems like wasted money.
Are there any competitions, or online clubs where a guy could really dive into it? I guess from your statement "I wish I would have started PLC when I was 12, I would be rich by now." that you work with plcs at your job.

Again, many thanks.

ps Dad edits my posts and corrects my grammar. Any mistakes are his.LOL

Actually look at the top of this forum and there is a tab "Learn PLCs" I think they have a book that is not very expensive, that would be a good place to start.

Also just come by and read the forum every day, I learn lots here, there are many good folks that can answer just about any question you can ask. And I also learn from reading other peoples questions.

I do some plc at my job, I am the electrician on a 340 foot process trawler in the Bering Sea.

Keep at what you are doing and the sky will be the limit for you in the future.

Looks like you are a hit here, already over 100 views of this thread in just an hour or so.

I have to run now but others may chime in with ideas for you also.

Hope to see you around the Forum.

BCS

Here is a Leap you may or may not want to take at this time.

If you want to download a version of the Automation Software that we work with here in the field you can get a free copy at this link.

http://www.rockwellautomation.com/rockwellautomation/support/plc/micrologix.page

Check with your dad first, then just download the free version of Allen Bradley RSLogix Micro Starter Lite.
Then also download RS Emulate.
(This emulator will allow you to simulate the automation software in real time on your pc without the need for an actual PLC.)

Once you have these two items downloaded you can go to the "Downloads" section of this forum and choose Allen Bradley.
In this section you can download any file with a .RSS and be able to open it with your new free automation software and run it on your emulator.

There are lots of different PLC projects already done that you can look through and learn from.

This is a big leap forward, but you seem like you are sharp, so I am sure this would interest you.

After you get good with it on the emulator, you can move up to running this same free software on an actual industrial type PLC, just look on E-bay and try to find a good deal on a Micrologix 1000 or Micrologix 1100.
(the software works with both of these models)

Also here is a link to the book I was telling you about.

http://www.plcs.net/bookwintop.shtml

Another web site you might want to look at is Thelearningpit.com.

BCS