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More accurate thermostat/controller for heater?


David R

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http://www.trademe.co.nz/electronics-photography/other-electronics/electronic-components/other/auction-474702740.htm

Same model but cheeper.

Current on Relay Contact:AC 5A/220V
So it looks like it will switch mains ok without a relay.

Accuracy: ± 1 deg C (-50 ~ 70 deg C )

Temperature measuring difference: ±0.5 deg C

Dont know if you want it more accurate though?

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http://www.trademe.co.nz/electronics-photography/other-electronics/electronic-components/other/auction-474702740.htm

Same model but cheeper.

So it looks like it will switch mains ok without a relay.

Dont know if you want it more accurate though?

So, his problem is that his heater has an accuracy of +- 1 deg. Why would you replace it with a temp controller with an accuracy of +-1 deg?

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So, his problem is that his heater has an accuracy of +- 1 deg. Why would you replace it with a temp controller with an accuracy of +-1 deg?

That is why I said I don't know if you want it more accurate.

I dont know how accurate the controller is on my chiller, it doesn't have 1/10 deg on the display but the tank never varies by more than about .2 deg by the two digital thermometers in it

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Ive been having a look on Ebay at the different thermostat options, and they all have a variance of 1c or .5c no real point in adding one in my opinion.

However, I'm like you, I love burning money on aquarium gadgets and what not :lol:

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  • 2 weeks later...

I looked at this problem when I had tanks too. There seems to be very little available that isn't very expensive. You can buy industrial controllers with the temperature accuracy you're looking for which also include PID control to help keep the temperature even more stable.

I currently have no fish (shame I know) but do have a controlled server room. I wanted to keep the temperature at a constant 25'C±0.5'C and humidity at 50%±2%. This was going to be possible with industrial controllers but at approx $2k for the parts I decided to make my own. I purchased an accurate humidity sensor and borrowed a high accuracy temperature sensor from work permanently (could have bought one for $1.50)...

Then I designed a controller using an Atmel AtMega16 Microcontroller + 20 x 4 Character LCD Display and made up a small PCB to put all the bits on. This switched a series of relays to control heating, cooling and humidity and speed controlled fans. Writing the C code was the funnest part as I'd never written code for PID control before so there was a big learning curve. I could have just gone with proportional control only but that would have meant accepting variations in actual temperature vs setpoint temperature due to the amount of energy required to control the temperature.

Are you interested in making your own - then you can still spend money and build something

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Are you interested in making your own - then you can still spend money and build something

Not right now, I've just bought the one above from fishstreet, and we're in the midst of hunting for a house/section and planing a build. Just need to get some adapters to get it up and running.

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  • 6 months later...

Right-o, time to bump this up seems how I've finally got around to buying a couple of adapters to get this thing running! Seems to be doing everything its supposed to, thermometer seems fairly accurate (if my memory of how far out my other digital ones are!), very easy to set, plenty of cable on the probe. Only downside is the length of the power cable from the plug to the multi-board where you plug in the heaters etc, only about 30cm!

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So far seems to be working very well, maintaining the tank at a more consistent temperature (within ~1C) than the individual heaters thermostats, and the display is easy to read and you can see at a glance whether the heaters are on or off. Worthwhile investment for anyone running more than one heater IMO!

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If you run two heaters each with a thermostat chances are only one will operate and the other will be backup.

Ah, so that's why I see one going all the time and the other only every now and then.

Better circulation could help

Why is that important? I thought heaters were meant to stay away from circulation otherwise it interferred with their thermostats?

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I need to write an article for the next Aquarium World. I think I might just write one on how to DIY your own temperature controller. Unfortunately to do this yourself using electronic bits you will need to know a bit about electronics but at least the info will be there for anyone who wants to give it a go.

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I need to write an article for the next Aquarium World. I think I might just write one on how to DIY your own temperature controller. Unfortunately to do this yourself using electronic bits you will need to know a bit about electronics but at least the info will be there for anyone who wants to give it a go.

Oooh, I'd like to see that.

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I need to write an article for the next Aquarium World. I think I might just write one on how to DIY your own temperature controller. Unfortunately to do this yourself using electronic bits you will need to know a bit about electronics but at least the info will be there for anyone who wants to give it a go.

Yes please Warren! :hail:

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