Thread: AC PLC ideas

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Does anybody know any other type of PLC's that are ready out of the box to run AC and not DC. I already have a boobox and would like something different than. I was checking out EFX-TEK prop 1 but by the time I start running AC, it's starting to add up in price or is that my best bet?

Joey,

If you're just going to be switching lights, motors, etc on/off, then a relay card would do fine. Something like this, maybe? The Prop-1 should let you run relays, as well. If you're okay with wiring up some stuff yourself, this shouldn't cost a whole lot (just buying the relays and some vector board).

- Hook

That brings me to another question. When would I use a relay over a PLC vise versa if that makes sense. Thanks so much for your help.

Well, I should point out that I've never used a PLC, just know a little bit (emphasis little) about them. They're basically industrial brains designed to do relatively rote tasks. They're available with different complements of I/O - analog inputs/outputs, and digital inputs/outputs. Most are expandable to have more inputs/outputs - like... for example, adding a relay card.

Relays on the other hand, have no intelligence. They're just electrically controlled switches. They require a small amount of electrical current to turn them on, but the output can control much higher electrical current. But you need some brain to decide when to turn them on or off. That's where the PLC, BooBox or Prop-1 would come in.

Which you'd want to use, PLC versus the others, depends on what you want to do, and what you want to learn. PLCs, BooBox & Prop-1 will be good options if you want something that will sit at the prop, without a tether back to a computer. PLCs will probably be the most robust, since they're made for factories - but you'll have to learn ladder logic, versus BASIC for a Prop-1, versus programming real-time for a BooBox.

- Hook

You know what is cool, if you have a PLC that is DC out only you can always hook up relays to those outputs to switch AC on and off.

I'm a controls engineer, and I design and program controls systems for small machines. I mostly deal with Allen Bradley PLC's. Although, I have done some stuff with Siemens, and Modicon. Allen Bradley has good equipment and software but can be expensive. For doing simple Halloween type Input trigger/Output stuff.
You will need to learn ladder logic programming. It isn't really that hard to learn. If you are going to use a PLC for controlling your props you need to decide the voltage of your inputs and outputs. A good setup would be one with 24vdc sinking inputs and built in relay outputs. with relay outputs you can actually run either 24vdc or 120vac outputs. you don't need to buy a $10k controller to what you need to do. For example you can use a mini PLC like a Allen Bradley Micrologix or a Siemens S7-200 line of PLC.
here is a link to a control panel on Ebay with a controller.
http://cgi.ebay.com/Allen-Bradley-Mi...item2309e48d50

You will still need to come up with the software which can be pricey.
The programming software for this is RS Logix 500.
I use a PLC in my Christmas display to control some parts of my display.
If you have any questions PM or Email me. I might even be willing to do some simple Allen Bradley programming. I have the software.(However time constraints may be an issue)