Best way to start

After reading the posts here over the past month, I finally decided to ask something. I am teaching myself programing at work (we use AB's using RSLogix500), and I want to know what the first thing some of you guys do. My boss (a self taught electrician), says to start with the I/O's and go from there. I was wondering if this is how some of y'all start, and if not what other ways do you get it going.

Look at the top of the page here and "Learn PLCs", order the books or videos, read the RSLogix help files (bad as they can be), go online and WATCH the program work, etc. I'm self taught also and these last two items are what I did to learn. Of course, later I found out about this site.

Be careful what you DO before you learn WHAT to do.

Good Luck

Well, you could start by programming the PLC to operate 16 overhead cranes. The cranes, of course, would be responsible for moving millions of dollars worth of equipment, weighing hundreds of tons, at high speeds. The dozens of people milling about under those cranes would be happy to know that you're on the job!

Or, you could start small. Somewhere on this board, you can find suggestions for a "traffic light" project.


I think "start with the I/O's" was intended to guide you during the testing phase of your project. But, it could also apply to programming. The simplest thing to do is to set up an input that turns on an output (an expensive light switch simulator). That'll teach you about addressing, and online monitoring.

AK

akreel said:

Or, you could start small. Somewhere on this board, you can find suggestions for a "traffic light" project.

Click to expand...

Or better yet, ask for an example of a traffic light program!

I dare you to...


hehe


John

Snow Dog said:

After reading the posts here over the past month, I finally decided to ask something. I am teaching myself programing at work (we use AB's using RSLogix500), and I want to know what the first thing some of you guys do.

Click to expand...

Get a simulator up and running with all of the switches and blinky lights. Fool around with that until you are comfortable with the programming environment. Try out all of the instructions, find unintended uses for them (seriously, just be careful about applying this knowledge in the real world ).

Basically, practice, practice, practice.

My boss (a self taught electrician), says to start with the I/O's and go from there. I was wondering if this is how some of y'all start, and if not what other ways do you get it going.

Click to expand...

My kind of guy

I got my start when a couple of engineers at a Goodyear plant asked if I knew PLC's.

"Sure, I said, what's a PLC?"


And whatever you do, do not ask for any traffic light examples. It tends to make people, ummm, grumpy. Really grumpy.


John

Snow Dog,

Im going to look at your question from another angle. When I start a PLC project I start by defining all my IOs, to use the dreaded traffic light analogy O:00/00 is red light O:00/01 is amber etc etc etc sometimes you have control over this sometimes you don't. Then I break my program into logical sections like north-south street, east-west street, turning arrows, walk signals.

Breaking up the project into sections allows you to get your head around manageable sections of operation. It also allows you to form a basic framework which you can finese into a more customised program.

I recommend you group your IOs into repeating paterns this makes it more manageable and use the symbols in RSLogix and give descriptive sensible names like RED_NS, RED_EW WALK_NS etc

Good luck

Andrew

I agree with your boss - start with the I/O Point List. Here are some other suggestions:

http://www.plctalk.net/qanda/showthread.php?s=&threadid=6906&highlight=structure

This comes up frequently on the forum - do some searches and see a lot of opinions.

sequence

Start with a sequence. What is it you want to do? And then, when are things supposed to happen? What makes the machine change from one condition (state) to another?

Break it down to baby steps. If, at any point, you think you have too much happening at one time, you probably do. Make it as simple as possible.

Then, decide what I/O you need to accomplish your task. Remember - if it can be sensed, it should be sensed. Know if your cylinders are forward AND backward, not just backward.

This will be a great adventure for you. Good Luck!

TM

Thanks guys,

I have a test bed set up at home, and have gotten a few small programs written, but this one is a little larger and more intricate that what I have done. I just wanted your imput on where ot start so I can keep it all logical and organized.

From all the posts that I have been reading, unorganized and unlabeled programs are the bain of any troubleshooter..so thanks again for your suggestions.