Backyard Aquaponics
A place to discuss aquaponics

is this the type of solenoid we are talking about?
http://www.wetearth.com.au/Product/Prod ... bCatID=122

Yep, that is what I was talking about. Basically any irrigation type solenoid will work.

Nova

Oh no................what have i done? I didn't bank on there being as many nerds as this here

Ive been restraining myself saying " keep it simple, use syphons, don't be tempted by the dark side of the diode.............." I may as well give up now LOL

I'll get the name of the PLC for you guys. I may be able to get a discount. i'll definatly get my mate on here to answer all your questions

But all that been said before will be easily handled by the PLC. We used the same one on a fruit shop cool room. this is what it did

* alternated compressors after every defrost cycle to average service life
* controlled defrost of cool room dependant of variables such as coil temperature, room temperature, time of day.
* controlled cabinet fans based on defrost and if someone was in the room.
*turned the light on and off

* a few other things i think

all the inputs and outputs were used, but there were still about 45 firmware timers free

Yes



its called evolution - by keeping it simple, all people have been able to understand and participate, this has produced all the diverse ideas and systems as is evidenced by "the followers" of this forum.

This is just another branch of AP needing exploration

My thoughts

Les

Hey Steve, why don't you talk to Murray and make a few up and sell them through his website I know Joel's got a link to his book on there

thought I might familiarise myself again with microprocessors etc and came across this:
http://www.oceancontrols.com.au/controllers/pixel.htm

might give others a bit of an idea

Steve,

NERDS R US

This stuff rocks, I miss the process control stuff after playing with it for so many yrs..now Im reduced to sellin cable n conduit n contactors etc YAWN lol........bring on the PLC's I say

Now u have a place for the UPS in your AP - the cycle continues

Don't think i've forgotten about you guys Am getting together info for yas

got it bad - went looking for some herbs and stuff for the little system and just happened to pass by "B" and checked out if they had solenoid valves, sizes etc... they do

Now there is a great find.

First I find this thread, and then someone has posted a link to this great looking device that can switch things on and off at various intervals (by the look of things anyways).

I have been looking at following:

Because my growbeds are (going to be) lower than my tank, every time I turn the pump on of course I create a syphon. At this point in time I am using a submersible pump in the tank, switched by one of those cheapie timers for 15 minutes every one-and-a-half hour or so. This gives enough time for the bed to drain. The return pump is controlled by floatswitch.

The supply pump really only needs 2 minutes with valve open, or 5 minutes with valve throttled back, and runs just over 10 minutes on the timer, so the last 5 minutes the return pump kicks in as well. Bit of a waste really.

I was going to look into not using the supply pump at all and simply using the syphon by using solenoid valvess in the pipe at the growbeds. Then I learned that "normal" solenoid valves ($25) need at least 70kPa to open properly, and my syphon with bugger all pressure needs so-called "direct acting" solenoid valves which cost around the $200. (and that at one per growbed) So that's the end of being able to use the syphon idea I think.

Also pondered the use of multiple float switches to turn pump on and off, but all that extra expense is not really necessary if you can just turn the pump on for say 2 minutes every say 20 minutes and open the corresponding solenoid valve for one of the 4 beds at the same time (or a bit earlier, and close a bit later than the pump is turned off for safety). This gives every bed a flooding and then 80 minutes to drain, and the tank is kept as full as possible at any time.

I would like to not run at night, for noise reasons. At the moment the last flooding of my one bed is at about 6PM and the first in the morning is just before 7 AM. Is this not good enough? Do you need to continue during the night? By the way, I do have a bubbler running 24/7 in the tank.

All it takes is some sort of controller, and the above linked controller for $130 seems to be able to switch 240V solenoids open and shut as well as the pump on and off by "simply" programming delays.

Might even be able to control the hot water flow for winter as well if you use an analogue input to turn yet another pump on.

So Steve, is this controller the sort of thing you are talking about with your PLC? And would it also have the output relays on board, and be programmable like this one seems to be without too much difficulty? Or is it even better than the linked controller?

Karel

Karel, jus loko at the link now been busy..........................

My thoughts on the micro:

CONS:
Probably not as versatile
harder to program
timing loops would have to be software written
Probably wouldn't have parallel processing of routines.
doesn't seem to have a RTC

PRO's
has all the 240V relays on board


All in all not a bad item, i'll get my mate to review it, he knows our application.

Stay tuned.

thanks Steve, looking forward to the reply

Night is the more critical time for DO in your system. the more algae or aquatic plant you have then the more at danger you are

Steve, had a chance to review any further, or look into the alternative $100 PLC you mentioned earlier?

I contacted the Pixel mob and send following query:

"I am looking for something to automate switching of pumps and solenoid valves, and thought that this controller might be able to do the job (with some spare relays left over to do other things with):

I need to do the following actions between 6 AM and 6 PM o a daily basis:

- Need to switch a pump 36 times ON and OFF for a period of 2 minutes during 24 hours (3 times per hour from 6 AM to 6 PM)
- Need to activate a solenoid valve 9 times for 2 minutes every 80 minutes (to coincide with a pump cycle)
- Need 4 of these solenoid valves switched to make up the 36 times of pump switching (ie the four valve timers are offset by 20 minutes)
- Might consider to add more solenoids later that may need to activate either 9, 18 or 36 times per day.

Don't need 7 day timer, as this will occur every 24 hours. Don't think there are too many (if any) digital timers that can do 36 times ON/OFF in 24 hours.

Would like battery back-up so I don;t have to reprogram everything after power-out.

QUERIES:
Is the Pixel controller suitable for the above simple program? I guess it would have to be programmed in a series of "wait" routines.

With the controller, does it need 24 hour power?

How do you control when the program starts and stops?

Could you run the control on a el-cheapo timeclock and make it come on at 6 AM, do it's cycling for 12 hours, and then turn it off?

Does the program remain in the memory when you turn power off? "

To which I got following reply:
"Hello Unfortunately the Pixel Controller does not have a real time clock"

So then I thought, well so what, counters or counter loops should be able to work out 20 minute intervals?

(READ ON in next post, both to up my quota and to keep the size of this one down a bit)

Karel