PLC Question

Thanks John! Much appreciated.

Thanks Paul, I will check it out.

What PLC's do you have experience in programming? What PLC's does your customer already have in use at their facility? What PLC's does your customer have the best experience with? What are your speed requirements? Who will be supporting the system?

Sometimes the answer is dictated by experience, cost, tradition, market share, etc. There are a number of PLC's that will meet your I/O requirements, but don't make your selection based simply on this. You will become disappointed and your customer won't be happy.

Hi BDThompson,

Thanks for your response.

I have programmed Mitsubishi, Omron and Festo PLC's in Ladder, Statement list etc. This is going to be used for a sign on one of the casinos I manage.

As you can see it was neon but it all got damaged in the last hurricane, I would like to replace this with LED strip lights (IP67). I would like the sign to fan up and do some cool animations that can be adjusted when required. A PLC with relay outputs would be sufficient as there is no need for faster switching.

The reason I need the inputs is because I would like to be able to switch the sequences to different programs. and switch it on and off.

A MicroLogix 1500 can accept up to 512 I/O points, but it only has 4K of memory so the program had better be very simple. Still, with only 10 Inputs, I can't imagine that this is very complex.

The 1764-LRP processor has up to 10.7K of program memory - and IMHO it's a pretty good instruction set.

Yep, my bad. Didn't flip the page...

Thanks John

If a complex program is needed, it would be relatively easy to have a different controller with far more memory doing the intelligent bit and driving the MicroLogix 1500 as a simple input/output device only......

Sounds like a good method and was used well over 30 years ago by many computers of the day, separating jobs and tuning the individual modules for best speed at all times and not giving mundane task to high speed units.....it actually makes faultfinding easier in most cases.....

If I haven't explained it well my apologies and do tell me and I will try and explain it better....

Thanks for the input JRaef.

WAGO is the best in my opinion.

Looking at cost of hardware, software, programming experience, ease of maintenance, I am also more inclined to go with Wago for this application.

It appears to be a one time use where ease of use is a big factor. Wago products are easily expandable, come with free programming software (61131) and each controller hosts its own web-page for use.

Look into this. I think you'll be impressed.

If you were looking for multiple applications or with greater complexity of use and especially if you were selling this product to other companies then I would recommend an A-B micrologix.

Thanks for all the help guys.

I'd recommend using a cheap laptop to control this with remote digital I/O. This type of application is a dead-simple program with lots of data (light patterns).

What you could gain is all the power of your favorite programming language. I've gotten to like Python recently, but you could probably even drive this from a spreadsheet if you are so inclined.

One bit of awesomeness you could do is take that picture of the sign, and create a GUI where new patterns can be created by clicking lights off and on with your mouse and clicking "save".

The same GUI could give you a real-time display of what is going on outside your building.

It's been a long time since I worked with it, but some names of distributed I/O I recall are Opto-22, Grayhill, and Wago (I recall Wago was very cool).

Here's only one example:

http://www.opto22.com/site/pcbasedio.aspx

Linux, too!

A sample google: "pc based distributed i/o"

And don't use relay outputs, you will wear them out fast. You want solid state outputs, then drive interposing relays for higher power. Use individual plug in relays so they can be easily and cheaply replaced. Use the ones with an LED flag so you will be able to see them working or not, you will thank me at troubleshooting time. I did a similar project with prison lock systems, the relay outputs died in less than a year and they didn't operate anywhere nears often as what you are looking at here.

This Wago looks quite interesting, thanks for the heads up guys. Thanks for the SSR tip JRaef, I was just about to add some normal relays to basket lol.

Hope you are all well.

Rob.