Problem In water sensors !

[yusuf]

Hello friends !
I have attached the required circuit diagram in my attachment !

Here in my circuit diagram you see that there is three water
sensor !

I have added the wire at the water sensor's sensing point to
sense the water. It is sensing water and working properly with
3 meters wire...

My tank is located on the top floor, the distance from ground
floor (where I want to place this circuit) is at least : 10 meter.

I want to add 10 meters wire at sensing point so sense the water from top floor.

I have tested by adding 10meter wires but the circuit was not working properly
it was false triggering !

So I have done several test and at last I came to 3 meters... It was working
properly with 3meter ....

Please help I want to add 10 meter wires at sensing point to sense water from my top floor...
I have attached the circuit diagram , please have a look !

Please zoom the circuit diagram for better and clear vision !
Help required friends :
Thanks in advance !

 

[duffy]

You need more drive! You are suffering from long-wire I*R drops! You have drawn the schematic wrong! IC1D, C, and B are shorted to ground in the first two sections!

 

[JimB]

Rather that volt drop on the long 10metre wires, I think that the problem is more likely due to the capacitance between the two 10m long wires.

If you really want to use that circuit, put it at the water tank, not 10 metres away.

JimB

 

[duffy]

OMG! Jim's not using exclamation points! But he may be right! You could try lowering the frequency to increase the parasitic capacitive reactance of the sense wires! Try increasing C1 to .018uF and make C2, 3, and 4 = .033uf! See if that helps!

 

[4pyros]

Put the sensor electronics at the tank and use the output of the CD4093 to drive the wires. You will forever have problums if you try and put 10 meters of wire between the probes and the circuit. The 10 meter wires can act like anntennas and pick up stray voltages and do all kinds of crazy stuff like when a lighting storm goes over head!
Save your self a lot of trouble and put the sensor electronics at the tank.

 

[yusuf]

First Thanks to all friends for replying me !

The 10 meter wires can act like anntennas and pick up stray voltages and do all kinds of crazy stuff like when a lighting storm goes over head!

Is there any method or way to remove stray voltages and lighting storm problems from circuit ....

 

[4pyros]

First Thanks to all friends for replying me !


Is there any method or way to remove stray voltages and lighting storm problems from circuit ....

Yes!!!!

Put the sensor electronics at the tank

 

[yusuf]

But I want the 10 meter distance from my tank !

 

[JimB]

But I want the 10 meter distance from my tank !

Then you should use a more appropriate technology for the water sensors.
Conductive probes are a silly idea anyway.
Floatswitches are a much better way to do it and you can use as many metres of cable to the control box as you need.

JimB

 

[alec_t]

I have tested by adding 10meter wires but the circuit was not working properly

I think I told you so..... months ago

 

[Boncuk]

Best way to go is using a pressure transducer.

There is just a PU (Poly Urethane) pressure hose necessary to be dunk into the tank.

A differential pressure sensor connected to it can be 100m away from the tank and the circuit will put out water level information accurate to 1cm of water height.

Boncuk

 

[Reloadron]

Best way to go is using a pressure transducer.

There is just a PU (Poly Urethane) pressure hose necessary to be dunk into the tank.

A differential pressure sensor connected to it can be 100m away from the tank and the circuit will put out water level information accurate to 1cm of water height.

Boncuk

Hi Hans

Suggested that day one of this project but the OP wanted probe sensors and timers and whatever. I guess getting a pressure sensor was the problem.

Ron

 

[4pyros]

But I want the 10 meter distance from my tank !

"Put the sensor electronics at the tank and use the output of the CD4093 to drive the wires."
The 10 meters to the controller.

 

[Boncuk]

Hi Hans

Suggested that day one of this project but the OP wanted probe sensors and timers and whatever. I guess getting a pressure sensor was the problem.

Ron

Hi Ron,

a differential pressure sensor hasn't been taken into consideration from start.

Having worked air movement for 18 years I swear that nothing can beat a pressure sensor.

Other than the bulky pressure sensors made by Furness controls Motorola pressure sensors are very small and don't lack accuracy and linearity.

Of course it takes an instrumentation amplifier to get rid of the inherent offset error of 1mV at zero pressure, but with the correct amplification set the sensor can be used to serve any A/D converter without problems.

Moreover, it doesn't make any difference if the transducer is located near or far from the measuring point. Even at a distance of 500m the sensor works precisely and reliably.

Here is my circuit design. Offset compensation is included.

Kind regards

Hans

 

[Reloadron]

Hi Hans

This project was spread over about 1/2 dozen threads. I absolutely agree as to delta pressure and somewhere way back there (maybe an ion ago) I suggested it. The OP is stuck on sensor probes and what became a maze of timers. Maybe a search of the OP's post will find the initial thread? Beats me.

I use pressure for accurate level sensing everyday and delta pressure with tanks at 3,000 PSI. Pressure has my vote. Hell, it also allows for real accurate measurement.

Nice circuit by the way.

Ron

 

[4pyros]

The op is convinced he has to put probes across the inlet to the tank to make sure water is coming out of it.
He also wants to turn the pump on every 1/2 hour or so for a short time to see if the tank gets any water even if there is no supply of water.
We tried to tell him the pump will burn up but he was not listening.