ladder diagram

[iant]

this is why we are telling you it is wrong.

Please understand
Lancie and I are in two different parts of the world - we are both telling you the same thing.
your program is incorrect and fails.
This will be the same feedback from other people on the site.

 

[theripley]

I bought a latching push button - too easy

I agree.

 

[Anirban Hazra]

Well I disagree because Mr.Lancie has tried it out in a wrong way due to my drawing not being clear to him and you have not tried it out at all so I guess I will wait for others who have actually tried it out to reply because this has always worked for me so it will need somebody to try it out the way I have said and tell me it's not working.

@Mr.Lancie
Now that I have cleared up what I meant by my drawing, I would like you to try my logic out and make Mr.Iant believe it works, because no matter what I say he does not seem to believe me.

 

[iant]

I agree.

for the record i was joking

 

[iant]

sorry Anirban Hazra I was trying to help you -
I give up - you already know everything
nothing more to learn for you.
well done - already a genius

 

[theripley]

for the record i was joking

Looks like I agreed with your joke.

 

[Lancie1]

Purpose: The same logic does not work across all PLC platforms.

I had just stated that i had used this logic in many programs and in many softwares without a glitch.

I have used similar Alternator Logic too in many programs for many different brands of PLCs, and have had many glitches. The same logic does not work across all platforms. You have to adjust it to fit the specific software.

Micrologix 1000 only one address is required,...

Yes, only one address for that specific OSR, but that ML1000 OSR must also have an Output intruction following it, or you do get the error warning "Missing Output on Rung!", just as I did when I typed in your program for a MicroLogix 1000 program. Here is the corrected version that has been working for years and years. See those small "1761-Micro" labels below the Input and Outut addresses?

@Mr.Lancie
Now that I have cleared up what I meant by my drawing, I would like you to try my logic out and make Mr.Iant believe it works, because no matter what I say he does not seem to believe me.

I did, and corrected it as shown.

Let us end this arguement. I think the main difficulty is that due to competition and marketing stategies, differnt brands of PLCs work differently. You cannot make blanket statements that will apply to all of them or even most of them.

 

[Lancie1]

Beginner's Lesson: To program any PLC, you first need to know the brand and model.

I see this aggravation repeated over and over:

1. New student or beginning programer works on a program.
2. Beginner asks for help, but assumes that all PLCs are equal, work the same, and run on the same software (not realizing that there are hundreds or even thousands of differences).
3. Now s/he thinks that somehow they can write a program without knowing WHICH PLC and which Input and Output modules is is supposed to run on.

 

[mag176]

hai guys i want to make this more interesting

by using counter,timer,set/reset or positive, negative coil its easy...

i want you guys to try it by using only normally open,close contact and coil

 

[Lancie1]

See what I meant? Here it is again. PLC beginners know that in every other part of their lives, any parts or program from one device will not fit or work on a different model, yet PLCs are somehow exempt from this basic rule - any old program will run on any old PLC (they think).

Mag176, please state the name of your programming software and the model of your PLC, and then your challenge for a contact-only Alternator will be valid. They don't all work the same.

 

[mag176]

lancie1
sorry i dint mention plc but i use ge plc and software is proficy machine edition... and
i know how to make this logic for any plc, i just try to make this bit interesting in a learning way....

 

[Lancie1]

Mag176,

If you have logic that will run on any PLC, then please post it right away. I will compare it to the several dozen versions already posted here over the years. Who knows, maybe yours is better.

 

[iant]

hai guys i want to make this more interesting

by using counter,timer,set/reset or positive, negative coil its easy...

i want you guys to try it by using only normally open,close contact and coil

FYI
I used to train apprentices with this type of question.
(HARD WIRE ONLY _ NO PLC)
design a 'Flip Flop' circuit that operates like this.
- EQUIPMENT LIST
- 1 Momentary Push button
- 3~5 control relays (4 pole) *only 3 relays needed*
- 1 light
- AIM
- when the button is pressed the light turns ON
- When the button is released the Light remains ON
- When the button is pressed again the Light turns Off
- When the Button is released the Light remains Off
then back to the beginning

the reason for this is to learn contact timing
PLC's, as Lancie1 has stated, all behave differently.
there is no easy, correct, one answer, but the understanding of the program is important.
one PLC will accept this following command
it flickers on and of with the scan rate - INTERNAL RELAYS ONLY.

     A           A    

-------]   [-------] / [-----------(A)

  

(ref: Fuji Microrex 80H)

 

[daba]

I've sat on the sidelines on this thread long enough....

"Why is it always the 'toggle' scenario?" - because it is an often needed functions in a control system, but also one of the hardest to achieve without an in-depth appreciation for how a "PLC" (non-brand specific) works.

Notice I said "non-brand specific" - not all solutions fit all platforms.

Some of the posted "solutions" could fail with platforms that use asynchronous I?O updates, such as A-B PLC5/250 and the Logix5000 series.

Many of the posted "solutions" could fail to remember the state of the toggle if the processor is "re-started", either after a power-cycle, or a mode change.

Please let us NOT believe that a single code solution will deliver all the requirements, across all hardware platforms.

We have to use our programming appropriate to the PLC we are programming.

 

[iant]

Ofcourse you are correct DABA
but when using 'toggles' the programmer needs to take into account a power outage.
I am sure most of us will do this.
But the Idea of this for students is to make them aware of the problem.