View Full Version : Teco for a reef control?

07/16/2011, 12:24 PM
Hey I am a Controls Engineer. Basically that means I am a jack of all trades. LOL. My responsibilities are electrical, combustion, hydraulics, pneumatics, and programming. So I sort of figure I could make a hell of a DIY reef controller. The problem is selecting a base to start from.

At work we build super complex systems and because of that we use full featured Omron, Siemens, and Allen Bradley PLC's. I'm most proficient with RSLogix 5000. Anyways although no one would dispute with one of these as a backbone you could do anything but the problem is that they cost a small fortune.

So I'm thinking a PLR (Programmable Logic Relay) would be a good start. The Teco Genie II seems to be a good start. The base processors come with 20 I/O and HMI. If you added all the expansions possible to 1 relay you would have on top of the 20 I/O another 24 digitial I/O, 8 analog Out, 4 PT100 in (basically a temp reader), and 4 analog in.

Seems like a good start! Anyone have a comment on this path? Anyone try something similar.

Ideally I would like to do the following:

-Auto Water Change
-Feed Mode
-Light On/Off (I have a IceCap 660's running T5's so not able to dim)
-Temperature Control

So what do you think? BTW once I decide what I'll go with as a platform I'd be happy to keep a log of what I have working and not working.

Vancouver Reefr
07/16/2011, 04:16 PM
Hi EodMike,

I too used to be in controls, so if it was me id be looking to use anything i could get for free, whether it be surplus from work or given as a favour etc.
However from the logic relay you have mentioned you will have no problems setting up a controller. So long as you can expand it later, as this project WILL get bigger, beleive me.

PLC's run bulletproof so i would just build in redundacy into the project by mechanical and seperate systems. IE 2 solenoid vavlves in series on your ATO output incase one fails open, a seperate timer to allow the ATO to run only for a small time period each day etc.

Sensors should be no problem, either using the 4-20mA protocal or 0-10vdc depending on which way you choose to go. Having a sweet HMI is always nice!

On my project i use 2 outputs for my heater and chiller. If my water setpoint gets too cold, it turns on power to the heater then i let the heater stat do its thing. If the heater fails on, another setpoint turns off the power to the heater. Same with the chiller, just on the bottom of the temp scale. Again this is redundancy and prevents heater/chiller runaway.

Hope this helps.


07/16/2011, 04:39 PM
I agree with redundancy. I guess your right I do have a few favors I could ask to be filled. One issue I am having is a pH sensor that isn't crazy costly.

As far as redundancy I do want to point out one thing. You can go to far in that direction. For instance with 2 solenoid valves you now have 4 points that could go wrong and not top off. I personally like to avoid that. So here is my for instance on the ATO.

3 float switches. One reads if the water level is too high. One reads if the water level is too low. 1 reads the level in the water reservoir. If its low turn on ATO pump and solenoid as long as the water reservoir level doesn't read to low and the high switch isn't made. Once the pump starts a timer does as well. If either the timer goes done, the low level goes off, the high level goes on, or the resevoir switch goes low then shut off the pump for the ATO and the solenoid.

You only have to worry about 1 pump and 1 solenoid failing off. There is almost no chance of a pump failing on especially if your turning off the pumps power source. So that by itself is a pretty bullet proof way to kill the adding of water but the solenoid is a back-up just in case. The timer, the high switch and the low switch all will work as a way to know if you may be overfilling. If the low goes off it should turn off the pump you have enough water. Set the high to almost the exact same level and that will tell you that your full and then the timer is a guess on how long plus a minute on normal ATO operation. These will work together to make sure you don't accidently tell the pump to keep running based on 1 bad reading. You would need 3 things to fail.

Anyways. I read your thread and it looks pretty awesome. I'm just getting a build sheet together. I wish I had it running as soon as my new tank is ready but chances are it will be added as my tank matures.

I'm sure as I go along I'll find that I don't particuarly like doing this chore. LOL lets make the AutoReefSitter do it. (working title)

07/20/2011, 01:06 AM
I see no reason why a Teco wouldn't work great. That's why I'll be using one at some point. You sure can't beat the price!

They recently upgraded them with a large revision. They've essentially doubled everything now, w/respect to the software. Unfortunately the programming tool is still just as opaque and confusing. They changed things so it's different confusing from how it used to be.