RS logix 500

I need more answers for my assignment. Describe the advantages of programming off-line when designing the programs i.e. Programming using the software and downloading to the PLC.

What answers do you have so far?

mandy said:

Describe the advantages of programming off-line when designing the programs i.e. Programming using the software and downloading to the PLC.

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Regarding posting on forums, then be a good girl and follow some simple basic rules.

The topic header should put the question or problem in a nutshell. If the problem is related to some hardware or software, then do put that in the topic header, otherwise don't.
"RS logix 500" doesnt have anything to do with your problem. It should have read "For homework assignment: Advantages of offline programming ?".

When asking for help from someone, who will hopefully do so despite it costs them their free spare time, then be polite by putting all relevant information pertaining to the problem in the initial post.
For example in your describtion of your task noone can see what the alternative to offline programming is meant. What might the alternative be ? I can guess (I suppose it must be online programming), but I really hate to guess.

Regarding homework assignments, then I think it is bad sport to ask for solutions to something that ought to be experienced by yourself. Try to ponder on what the answer might be. Questions like that is really not intended to be answered exactly correct. It is more intended to see if you have grasped the difference between the alternatives mentioned. A half-correct answer that shows you have understood these differences is allright. What would your tutor think if he received only exactly similar answers ?
What is fair to put on a forum, is more difficult problems that require much more work to finish. If for example you have come half-way through a code problem, but just cannot finish it becouse of some stumpling block, then do post your work and people here will jump to help you.

cheers.

ascot01 said:

What answers do you have so far?

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These are my answers: While the programming is off-line 1) I could use the email and even chat my friends, 2) I could ask help regarding the program, 3) and it is safe to use.

1. "On line" is referring to editing code on a running PLC. I'm missing the point.
2. Specifiy how it's different asking help when editing online versus offline.
3. This is the best of your answers. Please elaborate on your reasoning.

mandy said:

These are my answers: While the programming is off-line 1) I could use the email and even chat my friends, 2) I could ask help regarding the program, 3) and it is safe to use.

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These are my answers: While the programming is off-line
1) I could use the email and even chat my friends,
2) I could ask help regarding the program,
3) and it is safe to use.

OK Mandy good start A for effort if I were your instructor I would want asnwers restricted to just PLC. Therefore while true e mailing friends is irrelevant and gets you no points. Can you stop anytime you like? Why is this important? Will you screw up the PLC if you stop? etc etc.

2. OK good answer get a B+ BUT why? How are you going to ask for help and why is this a good thing relevant to the PLC program and PLC ability to run while you are doing this? How will it help you learn and most important how not to screw it up?

3. BEST answer of all. get an A Now go into some detail justifying. Name 3 ways it is safer.

For instance if you make an error while off line will it affect PLC operation. Big BIG issue and something to be very VERY careful with.
IF you are online the PLC WILL do exactly what your change tells it to do. What can be the worst case result of this?

You may wish to go into some detail describing forces what they do and what their impact may be. I may be open for correction on this but I think it is worth your time to at least learn about the implications.

You may also wish to discuss the ability to make the program run while off line for debugging and finding errors. My most frequent were typos ie 0 for O (zero for letter O). Really screwed things up.


Keep it up. You are on the right track.

Dan Bentler

mandy said:

These are my answers: While the programming is off-line 1) I could use the email and even chat my friends, 2) I could ask help regarding the program, 3) and it is safe to use.

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Remember online and offline refer to your connection to the PLC. In this context, it means nothing more - nothing less.

1) I can do this even while programming online... assuming I have an internet connection (though that's NOT necessarily a good assumption out on a plant floor) Programming online does nothing to inhibit your ability to use other ethernet based functions.

2) I can do this even while programming online. Again, there's absolutely no reason why you can't ask for help while programming online. I've been on both sides of that discussion hundreds of times.

3) Yes, it's safe to use. But I can make just as many bad mistakes programming offline as I can make online. When you dump the program you've developed offline into a PLC and put it into run mode, it doesn't matter anymore how or where the program was written.



So... let's think through this a little more. Ask yourself the standard set of questions: WHO, WHAT, WHEN, WHERE, WHY and HOW. WHY would I be interested in programming offline? Online? Is there EVER a benefit versus programming online? Is there ALWAYS a benefit versus programming online? WHEN in a project cycle might I be interested in programming offline instead of online? WHO might do WHAT kind of offline programming? WHO might do WHAT kind of online programming? WHERE can I program offline/online?

Ask yourself these types of questions. Believe it or not, but this type of question development process will help you as a programmer!

When I worked as a System Integrator (contract programmer...), I often had opportunities to work on systems that I had never seen before (and haven't seen since) I didn't know the process or the product. BUT by asking these types of questions, I was able to successfully complete the projects. It doesn't matter what product you make, the development process is always the same.

The hardest and most important part of any automation project is defining WHAT the system is supposed to do. You do this by asking these types of questions, then documenting your system. Before you ever start programming, you must document your system with a process flow, a flow-chart, a sequence of operations... (Though after you've been doing it awhile, you'll find yourself doing this in your head instead of on paper, but you're still doing it)

Only AFTER you've defined WHAT you need to do can you start defining HOW you're going to do it. In this phase you define your PLC requirements: Which PLC is best suited for the job? What are my I/O requirements? What are the communication requriements?

THEN you start programming.


Mandy, think about what I and the others have written above. Among those of us who have replied so far are probably over 100 years of combined programming experience! You should be able to extract three answers from that. We've given you alot of hints -- though we haven't directly given you any answers. We love to teach and help you learn -- that's why we come to this site. But help us to help you by applying yourself and what you've learned first. We will help, but we won't do your homework for you. Someday, we're going to be working alongside you. We want you to succeed and we want you to be safe to work with. (There are programmers I won't work with -- they're dangerous because they're not interested in learning the right ways of program development)

Good luck.

These are my answers: While the programming is off-line 1) I could use the email and even chat my friends,

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Mandy, you live in a different world than I did while programming PLCs. Chatting with friends would have been the very last thing I would have thought of doing while working on a difficult, stressful, mind-bending programming task. I don't think even the greatest so-called "multi-tasker" on earth could do that.

If you think you will be able to chat with friends while trouble-shooting a program on the job, you should think about changing career paths right now.

Personally, I would be afraid to work at a place where the PLC had been programmed "while chatting with friends".

Off-line programming will not immediately effect the operation of the machinery, but on-line program changes will. Your on-line changes need to be accurate and safe. Off-line, you have a chance to fix errors before they can cause damage or injury.

mandy said:

I need more answers for my assignment. Describe the advantages of programming off-line when designing the programs i.e. Programming using the software and downloading to the PLC.

Click to expand...

Programming offline gives you time to plan your logic out without worrying about crashing a machine or causing large amounts of downtime. If you make lot of program changes offline and then download that makes a lot of places to find your error if there is a bug, but different situations require different programming techniques.

The ideal way to program if you are using a PLC that you are not really comfortable with, or you are developing some logic that you have not tried or tested before, is do it online with a test PLC that is on your desk and not connected to an operating machine. In other words, you are offline with the plant floor, but online with a PLC, so that you can test your logic as it will run on the PLC. This allows to you to make sure the instructions operate the way you interpreted the manual, and allows you to debug your code by manupilating inputs and observing outputs in a safe environment.

Planning on doing all her work? I'm sure she'll have programs to write that you could bang out in under an hour.

jtn said:

Programming offline gives you time to plan your logic out without worrying about crashing a machine or causing large amounts of downtime. If you make lot of program changes offline and then download that makes a lot of places to find your error if there is a bug, but different situations require different programming techniques.

The ideal way to program if you are using a PLC that you are not really comfortable with, or you are developing some logic that you have not tried or tested before, is do it online with a test PLC that is on your desk and not connected to an operating machine. In other words, you are offline with the plant floor, but online with a PLC, so that you can test your logic as it will run on the PLC. This allows to you to make sure the instructions operate the way you interpreted the manual, and allows you to debug your code by manupilating inputs and observing outputs in a safe environment.

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Perhaps it would help if Mandy would explain what she believes the difference between online and offline is.

So, Mandy, what does "Offline" mean to you?

And, what does "Online" mean?

I'll give you a hint, in the world of PLCs it has nothing to do with the Internet!

OG

Lancie1 said:

Mandy, you live in a different world than I did while programming PLCs. Chatting with friends would have been the very last thing I would have thought of doing while working on a difficult, stressful, mind-bending programming task. I don't think even the greatest so-called "multi-tasker" on earth could do that.

If you think you will be able to chat with friends while trouble-shooting a program on the job, you should think about changing career paths right now.

Personally, I would be afraid to work at a place where the PLC had been programmed "while chatting with friends".

Off-line programming will not immediately effect the operation of the machinery, but on-line program changes will. Your on-line changes need to be accurate and safe. Off-line, you have a chance to fix errors before they can cause damage or injury.

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Proper attention is needed when doing any kind of machine/process programming. My standard reply to our IT/helpdesk folk is when you make a mistake someone doesn't get their E-mail or the spreadsheet does a wrong calc. When I make a mistake someone can get killed. You must learn the seriousness of what we do. In late 1984 we had a Pratt & Whitney tech doing service on a large CNC lathe. He was in a section of the program that disabled the overspeed function. He made a mistake on entering a speed and sadly he died 3 days later from the injuries sustained during the destruction of the chuck fixture.
Always, mind on task no matter how simple the task may seem.

What I'm amazed at is why everyone keeps replying to this (including me). Mandy has been working on plcs for 1 year (1st post 1/11/07) and is still asking this type of question. She (or he) is baiting everyone here and you keep taking it. It is kind of funny that a female name seems to get better treatment here than a male name (or it might just be my imagination).


This person is just hoping that someone will do the assignment for them.

And look, it happened.

Yeah no kidding! Look at response number 6! Your answer's irrelavent, but here's an A for effort!

Not very sneaky baiting by opening up with "I need more answers for my assignment" - that's usually not tolerated here.

Oh well, maybe she'll get that same help in the workplace. Or maybe I'll register a "Stacy"...

brucechase said:

What I'm amazed at is why everyone keeps replying to this (including me). Mandy has been working on plcs for 1 year (1st post 1/11/07) and is still asking this type of question. She (or he) is baiting everyone here and you keep taking it. It is kind of funny that a female name seems to get better treatment here than a male name (or it might just be my imagination).


This person is just hoping that someone will do the assignment for them.

And look, it happened.

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surferb said:

Yeah no kidding! Look at response number 6! Your answer's irrelavent, but here's an A for effort!

Not very sneaky baiting by opening up with "I need more answers for my assignment" - that's usually not tolerated here.

Oh well, maybe she'll get that same help in the workplace. Or maybe I'll register a "Stacy"...

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THE ENTIRE ANSWER IN # 6 WAS
OK Mandy good start A for effort if I were your instructor I would want asnwers restricted to just PLC. Therefore while true e mailing friends is irrelevant and gets you no points.

A for effort is like a kiss from Grandma.
You will note also NO POINTS. Was kind of impressed with the reality of the response.
If you are gonna quote me kindly use the entire paragraph do NOT do as the media does.

Dan Bentler