Water level switch... design needed

[Bad Inferno]

Planning my tank automation and need some idea's on level switches. I want two levels for my sump and two for my holding barrel. I have found the perfect controller which has 8x240VAC outputs, 8x24VDC voltage digital inputs and a couple of analoug inputs...ie pH or temp...All this is very easily programmed in the device which also has a RTC (real time clock) so you can even do lights, feeders etc etc.

My plan will be to open a fill valve (washing machine valve) gravity fed from a holding tank into my sump until the high limit reached. IF sump temp is low turn on Aux heater in sump and stop sump pump until sump is up to temperature. turn on pump and cycle new water through tanks then turn on drain valve until sump low level is reached. I can do this cycle once or twice a day and I am assuming it may take 30 min each cycle to heat the new water in the sump before turning sump pump back on. (This is so I do not need to keep my water reserve (80 litres) at 27 degrees all the time as it is outside.

I can get float switches for $25.00 each however difficult to fit in my sump. I was thinking about an electronic version using probes and very low voltage. I notice Tunze must use some type of IR device on there system, anybody know how this works ?

[DIY]

What sort of controller is it you've found and if you don't mind me asking - what's it worth?

for Ir distance detection I searched the net for quite a while once before - the general consensus seems to be that IR is unreliable especially for detecting water. Most of the stuff I found was using ultrasonic for rangefinding that could be adapted for a float level. The biggest concern I had was having the ultrasonic transducers above the water - humidty etc..

in terms of how IR distance works have a look at this link:
http://ccrma-www.stanford.edu/%7Egary/controllers/ir.html

I'll be interested to hear what you find

[Bad Inferno]

There are a number of small industrial controllers that could be used however few have a RTC and are priced at the point that is affordable for a fish tank ! Ebay has a number of second hand / new units from Omron or maybe Eurotherm however be careful as some need the software to programe that doesn't come with the unit.

I have been in industrial automation for 20 years and I like the looks of the following unit. I downloaded the prgamming software and it doesn't get any easier than this unit. It also has a SCADA interface (Supervisory Control and Data Aquisition) that you can run from your PC or maybe publish the data to the net for remote viewing.

As with any device that controls 240VAC you need advice from an electrician. You would suggest the 24VDC unit so the contact inputs, switches limtes etc etc all run off 24VDC (low voltage) which you can do yourself without killing someone !

There are other vendors selling this unit also however have a look at
http://www.oceancontrols.com.au/plc/fab_plc.htm

[DIY]

Wow!

12 inputs analogue or digital & a relay outputs, all packaged prebuilt with easy to use software and a lcd screen.

Sure puts the "aquarium controllers" to shame

I might have to rethink my plan to make a basic controller out of a picaxe - for that price it's built ready to go no hassles

thanks for the info - you say other vendors sell it, are they any cheaper?

[Bad Inferno]

Forget the "PIC" unless you enjoy writting code....(although I do it for a living) With the Pic the outputs are crap and you would have to purchase extra output drivers opto's/ relays etc.

My plan is to install this unit in a junction box wired out to standard 240VAC recpeticals where you can just plug in the devices and is safe. Mounted above my tanks

Download the prog software and have a play it also has a simulation function so you can test it out without the controller. With 8 outputs you can control everything. My only prob is that cannot find the manufactures web site, are they still around???. I need to investigate the SCADA and see if it has standard drivers as well Modbus or OPC once you get the signal into the PC. etc etc ONly shame is there is no Ethernet as the RS485 module is quite expensive if you want to remote monitor from a PC. Install IIS and serve the data on the web and if you are like me and travel a lot you can see what is happening. There is also an optional unit that if connected to the phone line can dial you up at work/mobile and provide voice commands programmed into the device...that option is ~350.00. Pretty cool your fish tank dialling you up hey !!!! (I think thats going toooo far)

I am on the hunt for solenoids and level switches and once I have this in place I will buy one. If you are interested maybe we can get a deal on two ???

Washing machine solenoids work on zero pressure already have pipe connections and are only $25.00 each. I am looking at trying to house the solenoid coil in a junction box to provide electrical protection...not for me however friends and if the kids start poking around. 24VDC solenoids are quite expensive.

DIYjunkie I think we've met you purchased my spare tank ? Hope it's now stocked with fish

[kalebjarrod]

you can buy the water level alarms from most wholesalers :wink:

bit busy tonight, maybe i can find the info tomorrow

[Bad Inferno]

Thanks ryan,
Was thinking about just using contacting probes however did not know if the fish would appreciate 1 khz @ 5-10V

The probe I am looking at is ~25.00 float switch and has an 8mm hysterisis so the contact does not go on/off/on/off etc. May mount two to a frame then install in sump. Next sump I make (if ever) I will get holes cut for level switches.
Cannot find the Ozzie Radio spares however the UK one has the same thing

http://rswww.com/cgi-bin/bv/browse/Module.jsp?BV_SessionID=@@@@1471481895.1100515671@ @@@&BV_EngineID=cccdaddddgheimicfngcfkmdgkldfhn.0&cacheID=uknetscape&3277968511=3277968511&stockNo=3970564

[DIY]

Yep that's me - the tank is about to be used, I made a cheap hood for it out of mdf and gave it to a friend who's struggling a bit for cash at the moment. Since he had to paint the hood anyay he's now painting the whole thing.

It's not going to be a discus tank though - he wants to get a juvi tiger oscar!!

I might be interested in buying one with you but I probably wont be ready until early next year. I've just put some new discus on my credit card :shock: - and then there's the whole christmas thing, party's presents etc.

Sounds like the way to go would be to house all the 240v stuff in a nice sturdy enclosure, perhaps a large waterproof polycarbonate one. you could put all the relays in there & have some standard sockets on the outside for pumps etc.

[Bad Inferno]

This is a 2005 project for me too however I can get the peripherals in place in the comming months for a smaller outlay. Not much point buying a controller if you don;t have the input's or outputs inplace. my drive is water changes and not to have to heat the holding container as my electricaity bill will be huge.

All is not lost when the Oscar gets toooo big for the tank (6 months) and he takes him back to the LFS then he can get a real fish :)

[DIY]

Have you thought of a washing machine / dishwasher level sensor?

It might need some research to find the right one. I have one out of an old model that is just an adjustable pressure switch, but I believe the newer style on some of the "intelligent" washers is actually an analogue design. could be as simple as placing the tube in your sump, mounting the unit above and connect to an analogue input on the controller...

[DIY]

Hi Bad Inferno,

have you had any luck with a water level switch design?

[Bad Inferno]

Yeah...I got two off ebay US5.00 each and awit delivery.
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&rd=1&item=4343195093&ssPageName=STRK:MEWN:IT

Plans have changed alittle as I have not found a real solution for a solenoid besides 240VAC.

I was going to gravity feed fresh water into the sump and control a solenoid however I think I will just use a small powerhead in the water reservoir and pump it into the sump. Have the water level switch turn on a 12VDC relay with contacts rated for 240VAC.

To empty use another powerhead (on a simple 240VAC timer) in the sump and just pump it out for 1 minute. Position the powerhead in the sump so that it does not empty the sump.

I was talking to you about the FAB PLC I think....Better to use a Direct Logics plc as this has RTD inputs although price is starting to increase dramatically and has just become a dream :)
http://web5.automationdirect.com/adc/Shopping/Catalog/PLC_Hardware/DirectLogic_06/PLC_Units

This PLC has comms...Modbus over RS485 which you could connect to your PC