did you consider smart relays? they are like mini PLCs and you can get one with analog input. the advantage is that it is programmable (software for many of them is free, like Zelio for example). you can expect to get industrial product for about $100 and few inputs and relay outputs.

you can get same thing using arduino or one of clones for fraction of a cost (dipmicro has Arduino clones for $11) but you still need to add relays.

 

Maybe this, if one of the positions is an end-stop:
http://store.concentricintl.com/store/main.aspx?p=itemdetail&item=LA-DUAL-CONTROL
http://www.surpluscenter.com/item.asp?catname=electric&item=5-1577-C

Ken

 

I want to thank you guys so much for the inputs here.

@Panic mode: From what I gather there is no way the smart relays will be able to handle the different positions. There is also the fact that this one will be run by a 12v battery, so the input will be from 12v-14v depending on the charger.

@KMoffett: You have lots of good inputs here, and I thank you again for that!
I looked at that one before I posted here.

- I have looked into a controllers like Arduino, and so far that looks like the best way.
As I want to be able to make my pre-sett my own positions from the control box.
Does someone know of a more commercial on then the Arduino? - With that I'm thinking of a more solid and trustworthy. As I read on some of the forums about Arduino that they are not made for use in boats, automobile, etc due to the complications if a failure.

 

If you want commercial grade and commercial co$t, try here.......
http://www.ab.com/en/epub/catalogs/12762/2181376/2416247/1239758/

 

...
Does someone know of a more commercial on then the Arduino? - With that I'm thinking of a more solid and trustworthy. As I read on some of the forums about Arduino that they are not made for use in boats, automobile, etc due to the complications if a failure.

None of the low end microcontrollers are intended for applications that subject them to life safety issues. The manufacturers' lawyers are very strict on this. It doesn't mean they aren't "solid and trustworthy"...it just means they will make you totally responsible if anything goes wrong.

Ken

 

From what I gather there is no way the smart relays will be able to handle the different positions. There is also the fact that this one will be run by a 12v battery, so the input will be from 12v-14v depending on the charger.

Not sure what made you believe that, this is a typical application for these things.

Anyway, it is your baby so decision is ultimately yours. I am just trying to shed some light.

If you want something rugged, perhaps consider industrial product. Even if not specifically marine product, they are designed and tested to work in many environments and difficult conditions (dust, cold, vibrations etc.).

PLCs are the big brothers of Arduino and Co. They have a lot of power you may not need, could take a lot of room and cost an arm and leg.

Smaller products (with less features but also less $$$) are so called "smart relays". Many of them are designed for 12V operation (automotive etc.). They are also programmable and have several inputs and outputs.

You can use one of analog inputs for feedback (potentiometer for example). You can use other inputs for whatever you like or leave them unused (maybe use them as start, stop, whatever floats your boat). You can use outputs to either turn loads (either drive your actuator directly or through relays for example). Even smallest version has 4 outputs. It is dead easy to make a small program for it, something that will turn on or off one or more outputs (in any order you like) when particular position is detected on analog input.

One thing to keep in mind is that to get reliable analog input, you need to use stable DC source for powering potentiometer. Battery voltage fluctuates and this means your reading will change even if potentiometer didn't move. Solution is to use small regulator to provide stable voltage just for this. You could use an LDO for example.

For example, typical range for analog input is 0-10V and sometimes 0-5 or 1-5V (check range and resolution of particular product). On some products like drives etc appropriate DC voltage is often made readily available. On others one need to take care of it himself. So you could use 10k potentiomer and 10V LDO. You can also use lower voltage than what your analog input can read but you are not maximizing range and resolution (feel free to use LM7808 or LM7805 instead of LDO). Suppose potentiometer gives you 0.8, 2.0, 3.9 and 6.4V when in positions 1, 2,3 and 4.

You can use comparator function to turn on:
output 1 when reading is in range 0.65-0.9V
output 2 when reading is in range 1.9 and 2.1V
output 3 when 2.4-4.67V (you can specify ranges as narrow or wide as you need)
output 4 when ... wherever.
If i've read correctly what you are trying to accomplish, this is more or less what you want.

The other way (just to mention) is to not bother with regulated power supply, one could just use another analog input to measure voltage of your 12V supply and compensate for fluctuations.

I have used few of them for small jobs (Alpha from Mitsubishi, Pico from AB, Zelio from Schneider, Logo from Siemens etc.), most of the time however I work with much more powerful controllers that run entire production line, not just one actuator.

First link for 12V smart relay happens to be this one:
http://www.cuny.biz/wp-content/uploads/2012/07/Zelio-DIA3ED1030801ENUS.pdf
On page 7 they mention two 12V models: SR2B121JD and SR2B201JD.