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Arduino-based SCADA guidelines

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Dannyx:
I have no idea of the distances myself. All I know, roughly, is that the closest is at 1km away from where "home base" would be (since it's installed right in their courtyard) and the furthest ones are 20km+ from "home base". There IS some documentation for this whole project, outlining where these stations are dropped along the canal, and I had a look at it myself at one point, but I didn't bother to remember anything because I didn't care at that point. The key word is "FAR" ! :D

I probably have hundreds of pictures, several for each of the 12, although there's really nothing different other than their location - the boxes themselves are identical, so that's really all you need to see.

Temperature aspects: yes, I too thought of that. The temperature swings are going to be wild there! Freezing cold in the winter and boiling hot in the summer ! There IS actually a heater in there, in the form of a heatsink with what looks like a resistor in the middle of it, but it's not automated: someone has to go there and flip the MCB to turn it on. At the opposite end of the temperature spectrum, there is no fan to cool the box ! The box cools down purely by natural airflow happening through those vents, which in some cases is not enough. Some boxes are in the shade, under foliage and trees and stuff, which helps to a degree, but most are out in the open...

As a side note, I created a small automation for my car's windows using an Arduino Pro Mini, but haven't installed it yet and I'm actually concerned whether it would survive in a car in the middle of summer when the inside temperatures can probably exceed 50c ! Only one way to find out and that is to take my project which is still on its breadboard inside the car, park the car in direct sunlight and let it roast on the passenger seat for a whole day under the scorching summer sun and then test it :D This would replicate the conditions it'd have to face once I install it in the dashboard.

Renate:

--- Quote from: RoGeorge on January 25, 2020, 12:21:15 am ---Those boxes looks like they have no climatisation.
--- End quote ---
There is a circuit breaker for a heater.

Dannyx:
Yes, that is the heater I was talking about, but it needs to kick in automatically once the temperature reaches a critical level for whatever's in there (Arduino for instance)...

EDIT:......which according to this discussion, is -40ish degrees C ! https://forum.arduino.cc/index.php?topic=3928.0

Renate:

--- Quote from: Dannyx on January 25, 2020, 04:08:46 pm ---Which according to this discussion, is -40ish degrees C!
--- End quote ---
Err, you don't have to wait until it's that cold.
I hate to be low tech, but a normal bimetallic thermostat might be sufficient.

How disastrous would the loss of aeration be?
How often do the pumps die?
How often do the air jets clog?

For monitoring I think a pressure sensor tee'ed into the air line would tell you what you want.
No pressure = dead pump.
High pressure = clogged lines/jets.

For easy availability, consider using an automotive turbo manifold air pressure sensor.
There are many common ones that run on 5V and have a range of +/- 100kPa (+/- 1 atm, +/- 14.7 PSI).
You don't need the vacuum part of the range.

Dannyx:

--- Quote from: Renate on January 25, 2020, 09:30:57 pm ---How disastrous would the loss of aeration be?
How often do the pumps die?
How often do the air jets clog?

--- End quote ---

By no means "disastrous" - some of these don't work to begin with and have been down for years on end now (which is where we come in to restore them when the project finally gets approved and commissioned).

Given that they run all the time, I'd say they die after 1 year in the best of cases, if not more often than that ! The bastards are surprisingly expensive to purchase new ! Crazy prices for what's essentially a large aquarium pump ! Thankfully, our marketing department, or whoever's in charge, managed to find us a website which carries diaphragms and other parts for them to at least cut down the costs of fixing them. Even these aren't cheap, hence why I think it was appropriate to also create a schedule for them, so the poor things wouldn't have to run all the time. Sure, this could very well be implemented with one of those plug-in timers, as a crude and quick solution, but there's a problem I spy: I don't know about others, but the particular timers I have around the house tend to run fast, so they drift around 5 minutes per month, requiring adjusting every now and then to make sure they're still accurate...not something you want to do in a semi-industrial environment. Sure, this could be made part of the monthly inspection we conduct on them anyway, but still...

OFF-TOPIC: Here's another photo of the actual tank where the air ends up, just so you get a better understanding of what these things actually are. Water comes in through the fitting on the far right and exists through the left where that metal shield is. Air comes from the pump, through the 4 valves and down to the bottom of the 4 compartments where the bubblers are. I have not seen these to know what they actually are. They could be proper components (diffusers ?), or they could just be something as simple as a piece of pipe with holes in it. The 4 chambers are connected at the base. As the water is agitated by the air, any remaining solids get separated from the water and they get caught in what resembles those egg trays in your fridge :D These are installed horizontally just below the water line. You can just about make out one of these very faintly in the top-right of the rightmost chamber. As more and more water enters the basin, the level eventually reaches the drain on the left where the "clean" water goes on its way into a sewage pipe or back into the canal directly, depending on the location of the station, and since the sediments are now at the bottom of the tank, the top of the body of water is "clean"...that's the idea.

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