PLC Controller

Lampshade · #1 09-26-2009, 03:50 PM

So looking around EBay the other day i managed to pick up a PLC cheaper than most light timers. So, i bought it, and started thinking of the endless possibilities of having a PLC for my tank. It's just a small PLC(8inputs, 2analog, and 4 outputs), its expandable to more, so i'll be keeping an eye on EBay for deals. While i wait for the PLC to ship i've started writing a program for it. I have a thermocouple/tranmitter, so i have temp readings, which i can put on the display. I've seen PH monitors, but i think i might be able to find something more usefull for that second analog, possibly Salinity, or something else. So far i Have:

-Light Timer - the reason i got it
-Over Temp. Shutoffs - Heaters off, fans on, still hot and the MH lights will turn off
-Feed Cycle - Main Pump off for 15 min, and future output for a auto pellet feeder
-AutoTopoff - figured i could make a cheap float sensor/solinoid setup
-Skimmer Full - Another cheap float sensor, that just pops up on the display when the skimmer's full

I've seen that other people have PLC's in their tanks, and my biggest question would be, what is worth automating? What is usefull? There's usually a way to automate something cheaper than a night out, so what would be a good idea for something to try?

tikkle · #2 09-26-2009, 05:18 PM

Do you have a sump?

mark · #3 09-26-2009, 05:58 PM

I've got a PLC with dozens of channels and all I ended up using it for is to control my heater then a fan for evaporation. Overkill but is good though as my temperature is steady.

banditpowdercoat · #4 09-26-2009, 06:52 PM

Sounds like you got a Siemens LOGO! I have a few of them running my tanks and ATO systems.

Skimmer full, use the float to control the skimmer air inlet. No air, no skimming, no chance of overflowing and spilling on your floor when your away or don't notice the full light.

Lampshade · #5 09-26-2009, 09:00 PM

Quote:

Do you have a sump?

Yes, i have 10g sump on a 55gal tank.

And yes, it is a Siemens LOGO!, great little things, used them at work for pretty much anything, half the time they're cheaper than buying relays. I like the idea with the air shutoff on the skimmer. I'm sure princess auto would have something that will work well for that, i'll see what kind of contraption i end up with.

tikkle · #6 09-27-2009, 05:26 AM

I am using the controller mainly for auto top-off. When I was setting my tank, my bigger concern was over filling. My setup have 3 float switches in the sump and 1 in the tank. In the sump, 1 for top-off, 1 for low level, and 1 for high level. If the top-off switch doesn't stop the fill, the high level will. If sump water is low, turn off the return pump before pump goes poof. In the tank, if your overflow is plugged up, float switch will turn off the return pump. I programmed to have 30mins delay, then the top-off pump turn on. I use aqualifter pump for top-off because I want a slow top-off and if something wrong will the pump, the worse case is no top-off. Unlike using solenoid valve, if the valve stuck open, you know what happen.....

And of course individual output should be fused. You can do so much will that little thing. Have fun with it!

Is that a AC input or DC input?

banditpowdercoat · #7 09-27-2009, 12:21 PM

Quote:

Originally Posted by Lampshade

Yes, i have 10g sump on a 55gal tank.

And yes, it is a Siemens LOGO!, great little things, used them at work for pretty much anything, half the time they're cheaper than buying relays. I like the idea with the air shutoff on the skimmer. I'm sure princess auto would have something that will work well for that, i'll see what kind of contraption i end up with.

Ya, They are great. I got a 16 input one controling my AT for 2 tanks. Soon, it will control water changes too. Then I have a Logo runingthe lighting for my tanks. I am always searching for a new version Logo though, last of the serial# 0BA6 those, you can hook th Logo TD display to. Then it will have feedback and easier visual monitoring

Lampshade · #8 09-27-2009, 12:36 PM

Quote:

Originally Posted by banditpowdercoat

Ya, They are great. I got a 16 input one controling my AT for 2 tanks. Soon, it will control water changes too. Then I have a Logo runingthe lighting for my tanks. I am always searching for a new version Logo though, last of the serial# 0BA6 those, you can hook th Logo TD display to. Then it will have feedback and easier visual monitoring

The new ones also have 4 analog inputs, which would be nice, i picked up a 0BA5, should work out alright, the TD display would have been nice though. The mini diplay screen is pretty customizeable on the older ones, so i'll see what i end up with on that.
I'm trying to find a way to use LOGO!soft comfort for the monitoring, and then use remote PC to be able to get info from my phone. I jsut need to find a way to have my LOGO! wirelessly transmit, so that i dont need to do house reno's hiding a cable.

banditpowdercoat · #9 09-27-2009, 01:35 PM

Hmm, sounds inrteresting. I know about the analog inputs on the new Logo's. I use them all over the mine site here. Great little stand alone processors

. Love the PT100 input modules. Direct temp measurement. Omega.com is great for sensors too.

Are you an electrician by chance, or just fooling around with them??

Lampshade · #10 09-27-2009, 03:13 PM

I picked up a PT100 thermocouple with a 4-10mA transmitter, seemed cheaper than the PT100 module for the LOGO!, i'll just have to see how accurate it ends up being.
Transmitter
I took some courses with PLC's and industrial control, i used to work building custom industrial automated machinery. One day i'll have my own shop so i can play around again, but as for now, between a baby and a salt water fish tank theres not much money left for playing