New to plc advice please

I have no experience with plc's as of yet but I want to get started with an on going home project implementing various functions and complexities over time.

The project
I have electrically operated windows with individual wall mounted rocker switches, I want to replace these switches eventually with a central control hmi touch screen where I can control individual windows and multiples eg open/close all.

The electronics for the windows is built in to the frames, they take a non latching input from the switch, up for open down for close.
I intend to take the output from the existing switches to inputs on a plc and then send the command to the window via volt free contacts from the plc.

I want the controls for the windows to be separate from an hmi with an interface that will allow different systems to communicate with the window control functions via programming. Im thinking rs232 rs485 but am unsure.

To add some more interest I intend to have one controller for upstairs windows and one for downstairs windows linked via a communications interface.

These are goals that I am looking to implement in the future one step at a time so choosing the right plc first is paramount to keep costs down etc.

So first things first I need help to decide on a modular plc that will allow me to expand capacity over time.

I have around £200 to spend on a plc can you please advise discuss on recommendations and or highlight any issues that may arise from my brief project description.

Thanks

I am a student in the US and after watching some videos on youtube.com about building home PLC units for educational purposes, I have ordered components from ebay.com. I have cheap input/ output devices being shipped from China and I bought used Allen Bradley Micrologix 1000 plc units. You can download the software for these PLC units from Allen Bradley for free. I also ordered 24vdc power supplies and communication cables. I found everything I needed to get started from ebay.

Welcome to the forum,

I think a good start would be to take into account the IO involved with you system. For this you need a rough design. This is important if you want to spec the hardware required.

There are many types of PLCs with varying cost and capacity limitations.

I think you need to look at second hand options as the previous poster mentioned. Be it that you will likely not get any support from the manufacturer. Im also not sure if the software licensing would be free for any of the packages. I highly doubt it though.

I also suggest you go through the tutorials on the site and read some of the review on the different types PLCs.

Good luck

I am looking to do some home automation (although perhaps a little more involved than what you have idealized) I started off with the idea of WonderWare and Allen Bradley gear, however I think now I may be leaning towards DirectLogic PLC gear and OPC Systems.

The DirectLogic gear is very reasonably priced on ebay. OPC gets pretty expensive, the main issue is buying the KepServerEx license for your protocol ($895) but the HMI portion of OPC starts at $195 and goes up depending on which features you want and how many tags.

Maybe starting with the DirectLogic gear and then implementing a OPC system when the funds allow would be a good path?

http://www.automationdirect.com/adc...eries_PLCs_(Micro_to_Small,_Brick_-a-_Modular)

The DirectSoft programming is free and full featured for the first 100 words, if you need to do more it costs $395 retail.

http://www.opcsystems.com/products/products.php

Neal

Maybe a micro800 series PLC from Rockwell is something for you? Free programming software and the PLCs are pretty inexpensive.

After some extensive digging into the software, I have becomea big fan of automationdirect's Do-more. The software is free, powerful, and includes a true simulator. The Processor fits the DL205 hardware, or you can get a TerminatorIO processor as well. A rack and IO can be found cheap on EBay.