Beginner needing help with a project (hope this works)

Hey Guys,

This is my first post on the forum. I was reading around for a bit today and decided Instead of trying to dig up everything, maybe I should just ask around. I have a project I am working which needs to activate some devices. The project will be powered by 120VAC and I will have to activate around 4 different 120vac outputs. I have to be able to turn those four outputs on at different times and different intervals. Some outputs may have to be on for hours some for minutes/seconds etc. I have a microcontroller (http://arduino.cc/), which I will be using to read multiple analog and digital sensors. I am trying to find a small footprint way of activating different outputs at different times. I have looked at some plc's and also the programmable relays (a.b. pico, easyboard, etc.) I am looking for something small and something on the cheaper side. I was wondering if you guys could point me in a better direction. My PLC knowledge is very limited. I was going to go with a programmable relay, but I don't want to be to limited in case I want to use it for a larger project. I also figured a plc might give me more experience in case I ever wanted to look for a job in that area. It would be cool to hook up all my sensors to a plc like you do with a micro, but I don't know enough about them, or if you can even do that. Also what is hmi? some of the lingo I'm not familiar with yet. Anyways, long post, I appreciate any help I can get.

Thank You,

~Craig Nettleton

P.S. Sorry if this is a duplicate, had some issues posting

An HMI is a human machine interface ie pannel veiw or touch screen. As for your controller I would use a small PLC one that the company offers a free light version of the software. Look into Koyo from automation direct or maybe twido from telemechnique. I was able to learn twidosoft in about an hour, then again I write in 5 different languages. Good luck with your project, and if you need any help email me at [email protected]

Thanks for the help. The koyo is only 24v, I need 120v. Also the other plc you suggested seems to be very expensive and discontinued. Any other help would be appreciated.

Thanks,

~Craig

Craiggy

A PLC will handle almost any control function you can think of.
In addition to outputs being controlled by inputs you have "internal" timers, counters, clock, etc etc that can control outputs.
With more "advanced units you get analog which lets you do proportional control, speed control, position control etc etc.

I do not think you should worry too much about the voltage of the item you would control at this stage. As a beginner I think it would be a good idea to get one with 24V inputs and outputs. That will make it easier to change wiring when you make mistakes without zapping yourself.
Have the 24 output control 24 volt coil relays
AND use MOV to protect PLC from inductive kick of relay.

If you want to do analog I do not believe you will be able to start with very small PLC. You will have to go up a step or two with the additional cost of software.

RECOMMEND
Start small with a very small (and yes limitied PLC). This will let you learn the basics at minimum price of unit and free software. If you royally screw it up and blow it up you are not out a lot of money. You also may find out you are not interested so why buy a bigger more expensive unit?

Dan Bentler

Check out the IDEC smart relay. Looks and functions like the AB Pico controller and for about half the price.


Jay