The CRAZY Project!

Umbra_Vipera

Umbra_Vipera

Professional Newbie
Aug 2, 2007
149
0
0
Trenton, Missouri
I've been out of the loop for several weeks due to the holidays and so forth, but I'm back with a passion. Just this morning around 3AM Central I completed my DIY ATO!

Here's a few photos for you to ponder. If you want a little more info check out my blogs here. I have just posted a new one today.




As always...questions, criticisms, and general comments are welcome!
 
WOW thats really high tech looks nice.
 
Ok.. ATO?

Automatic... Toad Ostracizer?
Automatic... Tank Overflo-er?
Automatic... Tank Oscillator?
 
Ahhhhh Without shaking "Tank" out of there I'd have never figured it out.

Umbra_Vipera; Excuse me but that looks about 4X more complicated than needs be. I doubt that you build to maximize complexity so could you give a run down on your functional scheme? I am most interested.
 
THE REPLY

kcress said:
Ahhhhh Without shaking "Tank" out of there I'd have never figured it out.

Umbra_Vipera; Excuse me but that looks about 4X more complicated than needs be. I doubt that you build to maximize complexity so could you give a run down on your functional scheme? I am most interested.
Click to expand...
The scheme is based around the simple function of adding water. Due to space limitations I can't use a seperate container so I'm adding water directly to the system. Now ask yourself this question, "What can go wrong when adding water directly to the system?"

Overflow your tank. Hypo-salinity. Low water levels. This last one is since it's automatic and the tank level shouldn't change you might not notice until you damage your pump.

Now build a system that knows when to add water with systems in place to prevent those three situations from happening. Throw in a few status indicators and override switches and your've got yourself an ATO system.

I'm going to break this up into parts so that people can read the ones they are interested in and skip the rest.
 
ATO - RO/DI SUB SYSTEM

This is the base of the system. We need to add water at a predetermined level to help maintain water quality and prevent my lazy butt from having to carry buckets. The use of separate container is out of the question because of space limitations and float valves are not ideal.

Why? Float valves are unpredictable. At a certain break over point they can bob causing the RO/DI to bounce off and on. Repeated on off cycles are hard on the membrane(s) and decreases the life and efficiency of the filter system. So how do we avoid that? Solenoid valves on a timer. Predictable and controllable.

The system is supposed to be automated however, so it needs to be told when to add water. So we use a float switch. The float switch determines the correct time to add water...but wait...a float switch can do the same thing as float valve...bob up and down. So now we're back at square one with the system bouncing off and on again. We need the float switch to activate a timer that will only allow the solenoid valves to open for a predetermined amount of time. I now present you with exhibit A.

P1270160.jpg


In the image above you need to focus inside the enclosure. Forget the lid for now and focus on the two matching green circuit boards on the right side. Specifically, the one on the left. These are designed for security systems. When a trigger activates the card, our float switch in our case, the card closes the tiny black relay and energizes our 120vac solenoid valves (and yes that is valves with an s). These cards can be set to open the valves from 1 - 60 seconds or 1 - 60 minutes. The best part...it doesn't matter what the trigger does once the card is activated. The card carries out it orders. It is possible that if the timing is not quite correct that you could have two cycles, one right after the other...but we've accounted for that...more on this later.

Now I've installed two solenoid valves. While these are normally closed valves, I wanted to have two in series just in case something freakish happens and one sticks open. $17 for insurance is worth the investment rather than who knows what in home repair bills.

Ok...great your adding water. What happens if you don't adjust the timing on the card correctly or you have back to back cycles? Exhibit B.

P1270158.jpg


You will see two float valves (white) in upper left of the image and you will see a float switch (black) that is close to the purple line. The black one is our call for water and the whites ones control our timer card. The power for the card passes through these float switch (in series) so that if either switch floats, power to the card is lost. When that happens, the relay opens, the valves shut and no more water.
 
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POWER SUB SYSTEM

While this the life blood of the system it is also what makes everything look so complicated. If you examine Exhibit A in the post above you see a whole lot of wires and it makes it look like there is a whole lot going on in there but there's not.

I personally am one of those folks that has trouble focusing on rat's nest wiring jobs where there are a bunch of wire nuts and you have trace each one down. So rather than confusing myself I used European Style barrier blocks. Easy to find and use. I turned these barrier blocks into distribution strips using pre-made jumpers in most cases. Some after thought design changes led me to use some wire to make my own jumpers later in the project.

Basically, you have household 120vac entering the box and attached to the distributions strips. You also have a 24vdc power supply in there for the electronics. An important note here. ALL of the float switches are using 24vdc power. Also, ALL of the float switches are tied back to a relay. This is important because the likely hood of a switch failing at these voltages is remote and the switches are protected from the power surges that can cause them to fail.

The 120vac powers the two outlets on the side of the enclosure, the 24vdc power supply, the solenoid valves, and is also wired to three switches that allow me to manually override on either electrical outlet or the solenoid valves should I need to.

The 24vdc power supply is powers all of the electronic cards, the main system relay, most of the lights, and the system reset switch.
 
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