Trying to get back into PLC 's 2

[railroaded]

I was involved about 10 years ago with PLC's, AB & Square D. An opportunity has arisen to retrofit some relay logic equipment for someone I know. My prior experience was with maintaining and making changes in programming as needed. I have never designed a system from the ground up. What teaching aids do you recommend that I can learn the process of converting from relay logic to PLC. I have time to study and learn before I accept the challenge.

 

[skills]

Experience, doing it is the best avenue!

 

[Buhsman]

Go to

http://www.plcs.net,

this site might be very helpful to you.

 

[ICman]

As long as it's a simple relay replacement project, you can use one of the smaller PLCs offered by most manufacturers, without having to learn a lot about code, etc. I used an A-B MicroLogix 1000 a few years ago and programmed it via a handheld programmer. It was easy and worked great. Some of these PLCs have PC-compatible software bundled with them.

These should only be used for non-critical systems (i.e. if it fails, it won't shutdown production or endanger someone, etc.). Since they're cheap, they aren't strongly supported by the vendors. You can consider them "throwaway" PLCs.

Otherwise, there are several courses available to help.

. . . Steve

 

[SteveMeisel]

Try:

http://www.thelearningpit.com

Steve

 

[nbucska]

I would write the program simply in BASIC. (write and
debug in GWBASIC, compile it in TURBO-,QUICK-, or POWER-
BASIC.) You will be surprized how much it simplifies
the programming.






<nbucska@pcperipherals.com>

 

[xyzz]

nbucska, the thread is about PLC programming.
Please, explain.

 

[cesarfranca]

Dear Railroaded!

I think you can use a project you know, for example, and start with this process. So get it and cut it if necessary for, I mean, if the project is too much big. Ok. Then think about your needs or ideas, never start with a big idea.
Imagine something simple. Of course, the possibilities in a controled system are infinite so think only about simple solutions, create a project for example to open the gate of the building you live. In this case you can think only about:

- A open contact that will be used as a command to open the gate;
- A open contact to inform the plc that the gate is opened;
- A open contact to inform the plc that the gate is closed;
- An output (any type) that will be the close command;
- An output that will be the open command.

Note: You can think about the possility to include lamps to each contact.

Ok. At this point don't think about motor protections and safety sensors, cicle times, data exchange trough a network, diagnostics etc. Let this for the future.

Create a logic program for this, just write down a flow chart. When finished, use, for example, a small plc like micrologix or other you can have access...

I think the next step is learn how to convert your project in a plc program and, if possible, test it. I have a lot of other practical examples, but you can start with this or other simple one.
After you get some knowledge about this matter, ask me, I have practical examples I use in my projects, real ones...

Good Luck!

 

[nedfluteholder]

Take buhsman's advice, look at plcs.net
There is a link from there to industrialtext.com
They sell a big fat book BUT you can download certain extracts from the BFB for free! The one I found most helpful is entitled 'Introduction to PLC Programming and Implementation - from Relay Logic to PLC Logic'
If you have the technical background but lack experience you need some pointers so you can be confident that you have covered all the angles, that you have organised your project properly. Check it out, you'll be pleased.
Good luck!

 

[musallam]

Go to

http://www.seaseimens.com/step,

you will find basic Course about SIEMENS S200,

H. Musallam