Brian's system so far

SuperVeg

Thats what I was thinking about Rupe.. Do you know of people getting nitrate spikes when harvesting ?
What's a good source of potassium ?

Brian Fanner

I have not fed anything more than a couple of pinches since early Jan. Potassium was my guess. Banana peels is it? How many? Is there another source of potassium?

For the greenhouse I have a fan', cowling and in process of building a flap vent to let the air out. Air will be blown in from the dust free side and vent on the dusty side. Thus the factory dust should hopefully) be eliminated

To control the fan I have in hand a gefran temp controller F030906 B21. It has 12 connectors and a small what looks like a 3 pin plug socket, very small. It has a relay too in a box. I used it before to control a branding iron. The branding thermo couple was in the element so now I need a probe/sensor of sorts? Anyone out there that can help?

I am officially naming the additional tank the koi tank. The other tank is the trout tank
The koi tank now has a venturi aerator and a decent shade solution is under construction.

Pics soon!

SuperVeg

hmm, if it was a standard type thermocouple you can make one. Just buy the thermocouple wire and strip the end, twist the wires together really tight and trim with cutters. Connect the other end to the input of the controller. But who knows what sort of temp probe it was...

DuiNui buried a few banana peels, ask him the details he mentioned in his latest system thread
This page
http://www.backyardaquaponics.com/forum/viewtopic.php?f=18&t=11386&start=45

RupertofOZ

If your pH is low... then you can use Potassium based compounds to buffer the pH back up... and provide a Potassium boost at the same time...

You can use Potassium Hydroxide.. a strong base, use with care... or Potassium BiCarbonate, readily available.. and often discussed before... :wink:

Potassium BiCarbonate... formely marketed as EcoRose... now as EcoFungicide... is an organically approved product.... and is also useful as a foliar spray to combat powdery mildew, and various fungi... hence it's name...

(Available at Bunnings)

Brian Fanner

So the sensor is just a loop of wire? A resistance as such? Resistance changes with temp...

Brian Fanner

It's a GEFRAN type 600 basic controller. I'm a bit dumb here! Read the spec sheet and it was greek to me.

SuperVeg

Thanks Rupe.

The wire is made of two different metals. When they are joined at the end a voltage difference appears across the join. When the temperature changes the voltage difference changes. That change is then compared to another similiar join in the measuring device, and that difference is used to calculate the temperature. Not a 100% accurate explanation, but you get the idea.

You can send the the documentation if you like and ill let you know if i get any ideas

scotty435

This might help (or not)

http://en.wikipedia.org/wiki/Thermocouple

Looks like you would calibrate the thermocouple against ice water and set this as 0 degrees C to get one end of the scale and water of a known temp for the high end (some use boiling water but you can't always do this depending on the thermocouple wires and if they have a coating). Basically you'd be making a plot of voltage difference vs temperature. Once you have the plot done, voltage differences detected by the thermocouple would allow you to determine the temperature. Voltage differences between the metal portions of the thermocouple would increase as the temperature increases.

Looks like your gizmo (I love technical terms :lol:

) lets you manually input the plot if you can't find one that's already done for the two metals of the thermocouple you're using. Here's some Barristas talking about making a thermocouple - http://www.home-barista.com/espresso-machines/diy-thermocouple-t2460-20.html

Hope this helps you out Brian - I may not be understanding where the difficulty is, I apologize for confusing the issue if this is the case. Cheers.

Brian Fanner

Ok. Thanks guys. Makes more sense now. I will need to get the thermocouple wires next then.

I thought perhaps this gizmo would be better for controlling the pump on the planned solar heater panel. If I can sense both tank water temp and outside roof temp at the same time to tell the pump when to go on and off would be cool.
Is there a cheap way to do the fan controlling? Thinking geyser thermostat...

Brian Fanner

Ok. Question. Can the thermo couple wires be like 60mm long? There are still the remains of the old thermocouple attached. Guess I can give it a go.

Brian Fanner

Ok. Got it powered up. Very little to play with on the front panel. Next problem is to get it interfaced to a computer I guess....looks like a small three pin plug...

SuperVeg

We need to make sure it is definitely a thermocouple probe.
If so, the cold junction will be inside the device. Most devices that measure temperature just use a "cold" junction at room temperature, it is accurate enough for most applications. A multimeter that has a thermo couple also has a room temp cold junction. If you leave out the probe, you can still use the multimeter to measure the ambient temp. (my wife steals mine for the baby room)

Another thing that will affect accuracy is what type of thermocouple wire it uses. Normally a 'J' or 'K' type. You need to get the correct wire. The wire can be as long as you want, as long as it is one continuous piece of thermocouple wire. It can be 50m if you like.
You cannot add length to it by adding ordinary wire to the middle (or anywhere), that will stop it from measure temp properly.

you can buy it from www.farnell.com or some other electronics supply warehouse.

DOH! Just read the datasheet, forget the stuff about types of thermocouple...
It can take any type. (Ill leave my ramblings to illustrate that it is important, nonetheless)
Wow, thats a nicely featured box !! (technical term scotty)

SuperVeg

Oh yeah, thermocouple wire is polarised... you have to get it the right way round. If you heat the end up and the temp goes down.... :naughty:

SuperVeg

you sure it is just 3 pin ?
RS-422 should actually be 5 pin...
unless your widget (scotty) only transmits stuff just for monitoring on a pc.

I'm trying to work out if you can just connect it to a PC serial port...
Don't try it unless you get some confirmation from me or someone else who can see electrons :laughing3:

Brian Fanner

Apparently I need a 10 dollar thermo couple jobbie. Probably just a loop of wire made to look smart. I tried my tiny loop both ways around :shifty:

but its not doing anything got a light bulb to test the output. Its got 5br which I can set and an alarm 1 which I can also set. The button on the left appears to do nothing. If I hold down the F button I get InF and then UPd 2.09 and then worryingly error 4. Perhaps I should solder the thermo couple. One is black and the other white...

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