Which PLC should I use?

I intend to build my own simple version of the "intelligent home" using a PLC. I have checked a few of the large manufacturers' web pages, but I have a hard time making up my mind about which model to choose. This is the reason why I'm posting this message, since I hope that you guys might be able to provide me with some valuable input.

What I need is a PLC can be wall mounted (no bare circuit board), preferably on a DIN rail. I need approximately 32 low voltage inputs, 32 output relays that can handle 240V AC and a few amps each, and four 0-10V analogue or PWM-capable outputs.

What would be nice to have is the capability to have a distributed solution, so that all I/O does not necessarily need to be located at the same phycial location. Further, it would be nice if one could connect two PLCs of the same type, and let them share I/O.

First of all, is a PLC the right thing for me to buy, or should I go for a PIC instead? The Siemens Logo! seems nice, and there are plenty of them available on eBay. However I got the impression that it does not have any PWM-capable outputs, and the analogue modules are quite expensive. I would appreciate alternative suggestions of which PLCs/PICs to use, preferably not too expensive.

Thanks!

look at the mitsubishi Alpha2, I currently use these to great effect on a few building control projects

Thomas,

the biggest issue in using a PLC for building automation is the control organism in your country. A home installation should be safe for every possible user, thus also for anybody without even the slightest idea about electrical safety. A PLC is intended to be used in an industrial environment, where only skilled people have access to the inside of the installation. If you are using a PLC in your home, you have to ensure that nobody can touch the internals of your system, so a wall mounted PLC will never do. The control organism will never release your installation for use. That's about the main reason why I always tell people to use genuin domotics if it comes to building automation. It's safe and it's agreed on by about every control organism in the world. Check the net for Nikobus or European Installation Bus to find out more, or you can turn to this page full of links to home automation sites.

But by all means: keep it safe, especially for the wife and kids!

Kind regards,

Why would you want the PLC to be wall mounted? Where are all the wires going to go?

If the PLC goes in a panel, what difference does it make if it is packaged or board level design? In talking about safety, an open board design runs primarily on 5 VDC power at the the component level. The 240 VAC switching voltage is more of a concern than the open design. Concerning safety, you can also change all your voltages in the panel to a low voltage, such as 12 VDC or 24 VDC.

The smaller "smart relays" will probably not have enough I/O or internal capabilities for what you are looking to do.

We actually offer two different products that would meet your I/O requirements, depending on your budget. Unfortunately they are board style.

How much do you want to spend for an automation solution?

You may want to consider a separate PLC with a touch screen or operator interface that can be wall mounted with the serial and power cables run to the display.

Just about any PLC will do what you are looking to do. The primary differences will be cost of ownership. If you are doing only one system, then you will incur the full brunt of the software cost.

One of the dilemas with buying items through eBay is that they don't always have the current documentation or software.

You could probably go through this list of manufacturers, researching the best product available for your application - http://www.plcs.net/chapters/links.htm

Hope this helps.

God Bless,

For a really simple and easy system take a look at the Dupline product from Carlo Gavazzi. This is an ideal product for your application.


http://www.gavazzionline.com/dupline2.htm

BITS N BYTES said:

For a really simple and easy system take a look at the Dupline product from Carlo Gavazzi. This is an ideal product for your application.


http://www.gavazzionline.com/dupline2.htm

Click to expand...

Yes that is correct. They also have a driver for many brands of plcs.

http://www.dupline.com/scheletro.asp?language=UK&Page=1

I like this... but pricey

http://www.eautomationpro.com/product/model.aspx?id=CATE_EAPRO_ERADAM5000TCP