Hi All,
Have a farmer for a customer with a large water tank for watering his fields. He would like some telemetry as to its state: full, half full, etc.. (Currently he uses the "There She Blows!" method to see when the tank is full.)
Anyone have any suggestions? Be nice if it worked over Modbus/TCP.
Many thanks,
-T
How far away? Why would he need the complication of TCP. I am thinking 2 wires, a variable resistor at the tank and a gauge that responds to it, similar to the gas gauge in a car. That would not require any power at the tank at all.
Todd wrote, on Wed, 29 Oct 2014 11:06:40 -0700:
I would ask in Alt.Internet.Wireless as it's actually pretty easy to put a webcam there, fed by solar, which then transmits the water running into the inside of your water tank, real time.
In fact, we have that set up for ourselves in some of our neighbor's tanks. You can transmit for 20 miles if you have line of sight.
He is within Wireless range
It supports Modbus with supports his Red Lion controller
He wants to show tank level next to his pump controls. Eventually he wants to have the pump automatically turn off through the Red Lion controller.
Like a huge toilet float?
Just posted over there on your recommendation. Thank you!
He has an extensive video camera installation. We could added it as one field on his display system.
Be cool to get telemetry though.
How about two weights hanging from a pully. The floating weight weighs more than the weight that hangs loose in the air. That weight that hangs in the air is spray painted fluorescent red.
The fuller the tank, the lower the red weight will be to the ground.
Telemetery is provided by an inexpensive pair of binoculars.
Similar I guess. I made a tide monitor with a drum, cable and a float, connected to a 10 turn pot.
I would suggest that if he really wants a modbus solution I would start with Red Lion. He can't be the first person to ask this question.
Made me laugh. Thank you!
Right now, telemetry is water spraying out the top of the tank. And you can see it all over the farm. No binoculars needed!
Todd posted for all of us...
Automation Direct should fix you up.
Depends on how much he wants to spend. If the tank is open at the top he can use a pressure transducer very easy. Here is one that operates over the Modbus.
Rosemont also makes single point switches. For that he will have to put a hole in the tank at the levels he wants the switch to activate.
Drexelbrook makes some level measuring transmitters that operate on a 4 to
20 ma loop type circuit and other devices.All depends on how much he wants to spend. He could put one of the point level switches near the top and have it turn off the pump and anoter near the bottom to turn the pump on.
AWESOME!!! Exactly what I needed. Thank you!
A friend answered this over on the home repair group
Todd wrote, on Wed, 29 Oct 2014 13:33:15 -0700:
Out here, we have a simple float that turn off the water *before* the tank is full:
On the outside, we have a "visual indicator" of the water level:
Then, we have floating weights, that turn off the water before the tank runs empty, so that there is always 1/3 of a tank for fire.
The whole thing is controlled by a set of pump controllers:
Then, there is the booster pump to boost the pressure in the house:
So, the control is well known (since all tanks have them). What you need to concentrate on is the telemetry.
Thank you!
Snow is forecast for us on Saturday and Saturday night. If there is enough power to overcome our Rain Shadow Effect, you should get drenched!
Todd wrote, on Wed, 29 Oct 2014 16:19:20 -0700:
We could use rain, since we're in California, where they (reputedly) fine you $500 for washing your car with a hose without a nozzle.
Poor grandkids though. I don't mind getting wet, but, they're gonna get it on Friday.
For your telemetry, this is one option (albeit pricey): Water tank sensing telemetry
Ralph Mowery wrote, on Wed, 29 Oct 2014 18:06:42 -0400:
You could even put a pressure sensor at the bottom, since a 10 foot tall water tank would have about 10 psi (roughly), I think.
Closer to 5
gfretwell wrote, on Wed, 29 Oct 2014 21:19:54 -0400:
Thanks for the clarification. That gives us a range for the pressure mat from 0 psi (empty) to around 5 psi (full).
I assume the output from the pressure mat would be an electrical signal (resistance?) which the OP could then transmit to his computer.
I'd suggest, for example, the Ubiquiti Loco M900's or Nanosation2 M2's (and others) to transmit the data.
Here are the datasheets:
And, I'd suggest a tiny Linux-driven TI microcomputer such as the Launchpad.
But, what pressure sensor mat would we suggest?
Actually, closer to 4.33 psig.
A cubic foot of water weighs 62.4 pounds, which is a good number to remember.
That 62.4 pounds exerts a pressure on the bottom surface of the cubic foot of :
62.4 pounds divided by 144 square inches, or 0.43333 pounds per square inch.So the pressure gradient of water is 0.43333 pounds per square inch per foot of water column height, or 0.4333 psi/foot.
The pressure at the bottom of a 10 foot tall tank of water would be
4.333 psi gauge.
Check out Omron, too. Years ago.... they were less cost than AutomationDirect and simpler to program for something like this.
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