Aquarium automation

Hello everyone!!! I've been assigned to write a paper about aquarium automation with plc for a course at university. No actual hardware will be bought so I have to describe the system and show the program in theory. So basically I want the system to perform the following tasks:
1) Temperature Control(cooling and heating when certain values are reached) Should I use an analog input for this one?
2) PH Control (trying to keep the PH stable opening valves that will pour the agents that will adjust it) Not sure how this will work cause PH should not change rapidly. I suppose I need an analog output to control the valves???
3) Lighting Control I suppose simple timers should do the trick
and a few other tasks such as alarms, water level etc which are fairly easy. Any help is appreciated

dimoutsa said:

1) Temperature Control...Should I use an analog input for this one?

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I think so.
This way you can show your Professor what you know.
You can explain how to convert the analog data into something that the PLC can use to decide when it is time to turn on the heater.

You should make a lists of all of your Inputs and Outputs, that way you can figure out what kind of PLC to Spec.


No Actual Fish will be harmed here, correct.:nodi:

Hello everyone!!! I've been assigned to write a paper about aquarium automation with plc for a course at university.
REPLY I kept both fresh and salt water aquariums so know a little.

No actual hardware will be bought so I have to describe the system and show the program in theory.
REPLY Are you going to use a PLC software to do this or simulate that also and use a different software ie Word,,,


So basically I want the system to perform the following tasks:
1) Temperature Control(cooling and heating when certain values are reached) Should I use an analog input for this one?
REPLY Thumbrule is fish can tolerate maximum 5 degree F change per day so temperature control is vital. The tighter the band the better so this puts you into analog right then and there.

2) PH Control (trying to keep the PH stable opening valves that will pour the agents that will adjust it) Not sure how this will work cause PH should not change rapidly. I suppose I need an analog output to control the valves???
REPLY acutally pH should not change that much in a salt water setup due to the high buffering of all the salts. Fresh I am not sure. Both are said ASSUMING you have the bacteria all working to deal with fish excretion. If you want to control it I would think analog sensing would be best then you could dose chemicals with a simple valve and timer setup. If fancy (and tank large enough) you could use a dosing pump with a VFD to control speed thus dose rate. Hmmm in your paper I think you need to set a tank volume assumption.

Salinity in salt water will need sensing. Water will evaporate and raise salinity then you would just turn on fresh makeup water to correct.

3) Lighting Control I suppose simple timers should do the trick
REPLY That would be easiest. Especially so if you are going to simulate actual sunrise and sunset using staged lighting ie 1/3 2/3 and all on.

and a few other tasks such as alarms, water level etc which are fairly easy.
REPLY If you are doing large tank then you need to control a circ pump in tank to ensure circulation of oxygated water thru biological filter bed media or what ever. Definitely sense this.
Water level is a good thing to sense.

Any help is appreciated

I had several aquariums (fresh water, largest was 55 gallons) when I was a kid.
I would recommend analog inputs for all measurements. But, I do not think you need analog outputs. You can use simple on/off valves and relays.

For lighting, if your PLC has a real time clock use that, so you can have the lights turn on/off at a certain time of day instead of an elapsed time.

One thing I did not see was how many water turn overs an hour you are looking at.
I always wanted to take my brother in-laws 275 gal. coral reef tank and automate it. He has 400 watt metal halides, 2 1hp pumps and all kind of cool rocks in there

Years ago I did the programming for the PLC system that controls the Aquariums at Moody Gardens in Galveston Texas. The one major component part you’re missing is the filtration system and turbidity monitoring (essentially for fish poop). There were dozens of huge sand filters that were cleaning the water. There might be a bank of ten filters on one aquarium, eight would be filtering water and the other two might be back-flushing (to clean the filter). Multiple MOVs on each filter to do the switching…. all monitored and controlled by PLC. The back-flush water then went through an effluent system similar to a waste water treatment plant and eventually flowed into Galveston Bay.


Check out the Aquarium at:

http://www.moodygardens.com/

I'm thinking big public aquarium. Maybe yours is table top.

I looked a commercial fish breeder's operation and was amazed at how critical temperature control (±0.6°F) was for breeding. I'm not sure if the same is true for non-breeding applications.

If you need cooling control, you need to figure out how you're going to pull heat out.

Conductivity is used to monitor brine solutions in industrial water softening apps.

Total dissolved solids (TDS) is probably a biggie for aquaria.

I suspect that serious commercial establishments monitor dissolved oxygen (DO) levels, as well, to ensure that the fish don't suffocate.

What about water level ?

How is the make-up water supply, which is probably from city water supply de-chlorinated?
What other treatment does it need to become make-up water? Salinity? aeration for DO level?

How is alarming on out-of-tolerance conditions accomplished?

First of all thank you all for your responses. Just to clarify some things the system I want to simulate will be a bit simple at first and it will go like this:
The aquarium will be a table top one with another tank beneath it that will act as a filter. Water flows from the aquarium to the tank bellow and with a pump it will be fed back to the aquarium. For this configuration I'd like to do the following:
1)Temperature control via analog input. If temperature goes bellow/above the preset value then the heater/chiller will be activated until that value is reached.
2)PH control via analog input. It will work in a similar manner with temperature control. In certain aquariums I've seen PH is adjusted by pumping CO2 to lower it and Oxygen(some use plain air) to increase it so I guess a couple of tanks one with CO2 and one with Oxygen and valves should do the trick.
3) Lighting control. For this I' ll use a real time clock as one of you suggested and do the dusk/dawn simulation.

So here are the questions I have:
1) I haven't really found a descent simulation program. Tried Automation Studio but it doesn't seem to support analog I/O and I've tried LOGO. Any suggestions?
2) I'd like the end user to be able to set the desired values for temperature and PH so I suppose I need some kind of panel for this any ideas?
3) I guess I have to pick which hardware I'll be using so I need some help with that also.

Mine at home uses a Wago 750-841, for the main reason that you can design the HMI in the CodeSys IDE and it will run as a web page from the controller. I can access the HMI from my desktop PC or my wife's Macbook Pro. It embeds JavaScript and Swing for gauges, buttons, etc. Very neat for the cost.

For the TDS and pH I found a couple ABB pH/TDS controllers on E-Bay. I actually bought an inexpensive pH aquarium probe and TDS solids probes. This works well. Also found some RTD transmitters on E-Bay and some solid state relays to control the heaters in the sump. Then standard relays and a contactor for the recirculation pump. The sump is actually a Rubber Maid tote with a bulkhead fitting in the side. It sits on an upper shelf with the pump/filter and chiller on the bottom shelf. The shelves are powder coated frame and the shelves are melamine to resist the moisture (bought at Costco). This arangement is in the basement to make the messy portion of the maintenance on the concrete floor and keep it out of the house.

Auto refill is a basic barrel with a submerged pump and several capacitive probes in the sump (redundant) for water level. Every few months I refill the barrel and add dechlorinator. The barrel must be opaque so that you will not grow alge.

Anyway, works well.

Darren

as it is only paper
water level with a float switch or a capacitive sensor.
use a PID loop and a water valve
etc.

2)PH control via analog input.

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In the PLCS.net Downloads section, someone posted an Allen-Bradley RSLogix PLC program for PH Control at a water treatment plant. It is located here:

http://www.plcs.net/downloads/index...ey&PHPSESSID=0ac421b3fd9b62f443b5231a3aabf612

Aquarium/codesys

dash said:

Mine at home uses a Wago 750-841, for the main reason that you can design the HMI in the CodeSys IDE and it will run as a web page from the controller. I can access the HMI from my desktop PC or my wife's Macbook Pro. It embeds JavaScript and Swing for gauges, buttons, etc. Very neat for the cost.

For the TDS and pH I found a couple ABB pH/TDS controllers on E-Bay. I actually bought an inexpensive pH aquarium probe and TDS solids probes. This works well. Also found some RTD transmitters on E-Bay and some solid state relays to control the heaters in the sump. Then standard relays and a contactor for the recirculation pump. The sump is actually a Rubber Maid tote with a bulkhead fitting in the side. It sits on an upper shelf with the pump/filter and chiller on the bottom shelf. The shelves are powder coated frame and the shelves are melamine to resist the moisture (bought at Costco). This arangement is in the basement to make the messy portion of the maintenance on the concrete floor and keep it out of the house.

Auto refill is a basic barrel with a submerged pump and several capacitive probes in the sump (redundant) for water level. Every few months I refill the barrel and add dechlorinator. The barrel must be opaque so that you will not grow alge.

Anyway, works well.

Darren

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Darren found your post very interesting, I looked up the codesys software you mentioned and it seems I've already used it with a IFM PLC but was branded ecosys.

I'm very interested in how you got your visulisation onto a web page.

I'm looking for and easy cost effective way to get data from a plc via the web and even control it.

Can you post anymore info on your own project please.

"I'm very interested in how you got your visulisation onto a web page."

There is not much to it. The CodeSys IDE has a simple integrated HMI. You layout your HMI in that. Then there is a checkbox somewhere that you check to enable the Web based HMI (they refer to it as WEB VISUALIZATION). Then when you download the program it will download the HMI with the program. Any OEM PLC that uses CodeSys run time may have the web visualization capabilities if they OEM has enabled it. So some of the other systems my have it, but I am only familiar with the Wago units.

Darren

For future reference:

There's a reference book on instrumenting fish aquaria, The Marine Fish and Invert Reef Aquarium by Albert J. Thiel.

It is quite extensive in its coverage of the basics, fitration, waterflow, water quality and analysis, lots on redox potential, and temperature and good coverage of instrumentation, albeit focused on stand-alone instrumentation.

I have a paperback copy. 3rd edition is 1988, there's likely newer editions.

Not very expensive from the used book web sites.



Dan

dash said:

"I'm very interested in how you got your visulisation onto a web page."

There is not much to it. The CodeSys IDE has a simple integrated HMI. You layout your HMI in that. Then there is a checkbox somewhere that you check to enable the Web based HMI (they refer to it as WEB VISUALIZATION). Then when you download the program it will download the HMI with the program. Any OEM PLC that uses CodeSys run time may have the web visualization capabilities if they OEM has enabled it. So some of the other systems my have it, but I am only familiar with the Wago units.

Darren

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Note that not every hardware platform will support Web Visualization. We have some Moeller PLC's that do support it but the Bosch Rexroth PLC's which also use CoDeSys do not support it. You can use the visualization so long as you are connected through the programming software but if you try to use internet explorer to get to their IP address, there is no web server there.