Need help to make Water Level Indicator and Auto Pump Control System

Thread Starter

imani9009

Joined Nov 8, 2013
1
I AM MAKING A WATER LEVEL INDICATOR AND CONTROLLING SYSTEM. I am confused with the circuit i want two ways of operation
First
The motor should only operate when water level is 30% or down, and whence operate it should stop at 100% level. 2nd it should not operate on 45 60 75 90 or 100 level. Every level indicates an led and 5 volt signal. Also if 45% indicator is on then 30%is also on. 60% on means 30, 45 % also on and further..
I have 5 volt relays with no and nc contacts
I have made this circuit but it is not fruitful as

20210905_170033.jpg
Because motor starts when the level is below 100 and stops when it is 100.
I have an indication circuit at this time in which I want to add motor controlling circuit Screenshot_20210816-212628_Daraz.png
 

Tonyr1084

Joined Sep 24, 2015
6,966
Shutting the motor off when it reaches 100% full might spill water over the top because the motor isn't going to stop spinning immediately when it reaches 100% full. The simplest approach is a float level switch that turns the pump ON when water is at a low point and turns off when near full. There are plenty on the market, and likely easier to implement than to take signals from your water level indicator. It's probable that your indicator doesn't handle enough current to run the pump motor. So I'd recommend NOT using your indicator, unless you don't mind blowing it out the first time you try it.

Do you already have a pump in mind? What's its ratings? How much voltage does it require? How many amps does it draw? Does it run on AC or DC voltage?
 

SamR

Joined Mar 19, 2019
4,298
How large is the water tank, volume/size? Square D makes quite a few residential and industrial pump controls on both level and pressure.
 

MisterBill2

Joined Jan 23, 2018
12,385
For controlling the water level in a tank of any size, that device shown is not suitable. It is a useful indicator, possibly..
To control the water level in a tank two switches sensing the level are required, both switches to be of the arrangement that when the level is below the switch. it is closed, above the set level the switch is opened.
The pump motor power will be controlled by a relay with contacts rated to carry the motor starting and running current, with one additional contact that also closes when the relay is operated. All the contacts will be open when the relay is not operated.
The coil voltage of the relay should be selected to be convenient.
The lower level switch should be in series with the coil voltage supply source so that when the lower level is passed the relay operates. The extra set of relay contacts should be in parallel with that switch. Thus the relay will operate and the pump will start when the lower level switch closes. And the motor will continue to run after the lower level switch opens. The upper level switch must be in series with the coil voltage supply source so that when the upper level is reached the switch opens the relay supply and the pump control relay is released, opening the motor power contacts and stopping the pump.
To use that display device in the photo will require two additional relays , each with a normally open contact, to be used instead of the two float switches. Those relays will need to have coils that operate on the five volts, and contacts rated to handle the coil voltage and current of the pump control relay.
 

SamR

Joined Mar 19, 2019
4,298
Typically, it is two switches, a HI level switch to start the pump and a LO level switch to turn the pump off after drawdown. For filling the tank, the logic is reversed. In some cases, for safety purposes, two pumps are used in case one pump fails to start. There are also level controllers made for this purpose. As I said before, check out the Square D catalog to find these controls and their circuitry for examples.
 

SamR

Joined Mar 19, 2019
4,298
The problem with SPST (or single contact) is chatter which may rapidly burn a pump up albeit common for sump and bilge pump control along with a manual ON switch. Typically for larger differential levels are two contacts, one HI (to seal in pump) and one LO (to open off). Also should consider Hand-Off-Auto switch wiring in addition to the level control. Still don't know what the TS is actually trying to do other than the bare bones. Need details.
 

MisterBill2

Joined Jan 23, 2018
12,385
One switch; a SPDT will work. Even an SPST switch.
View attachment 247467
What you describe here uis a sump pump, which is normally an open thing where dust dirt and whatever getting in is not an issue. What the TS is asking about is for a residential water tank control, which is generally intended to be sanitary for drinking water. Quite different, and usually enclosed. What I described is a standard industrial control scheme, not a drain pump control system.
 

Reloadron

Joined Jan 15, 2015
6,684
I have seen this done in a number of countries. The Philippines comes to mind. Utilities like water come and go at random so when water (potable water) is available the water is pumped from a feeder line up to a tank on residential house roof tops. Using a check valve to endure undirecting of water, no backflow. On the roof a bubbler system is used. Figure 27.7 inches of water column is 1.0 PSI. How much pressure it takes to push air (small air pump) is measured and correlates to tank pressure or water level. Read the air pressure and scale it to tank level. Float switches are another popular method and some even use ultrasonic.

Ron
 

Sensacell

Joined Jun 19, 2012
3,011
Here is my take on water tank level measurements.
Using sound well below ultrasonic frequencies, confined to a tube - planar waves.

 

MisterBill2

Joined Jan 23, 2018
12,385
If the TS actually has the level displaying appliance shown in post #1, and if the device functions as described, then using the five volt outputs to drive suitable relays, either solid state or mechanical, which wold replace the two level sensor switches in the circuit that I described, will serve very well.
The use of a pressure switch to sense the level demands a very stable switch and I doioubt thelong term reliability unless a very expensive system is used.
And if the system shown functions as claimed there will be no problem.
 

Tonyr1084

Joined Sep 24, 2015
6,966
What you describe here uis a sump pump, which is normally an open thing where dust dirt and whatever getting in is not an issue.
That's a good point. I hadn't considered that part of it. But I can also see an enclosed system where you can remove the lid to service the switch and float.
If the TS actually has the level displaying appliance shown in post #1, and if the device functions as described, then using the five volt outputs to drive suitable relays, either solid state or mechanical, which wold replace the two level sensor switches in the circuit that I described, will serve very well.
Yeah, that might work. However, that device is driving an LED to indicate the level. While it may be 5V (which we don't know) it might not be strong enough to trigger a relay. But I don't see how the pump would be controlled. When the water is below a certain level - lets say the bottom LED only - what's going to tell the pump to come on and run? OK, assuming that part is solved, when the tank gets at or near 100% full, how do you shut the pump off? I realize those are easy enough questions for us to answer, but what skill level does the TS possess to where he (or she) can build such a circuit? First thought that comes to MY mind is an XOR gate (or XNOR) But then as soon as you fall below 100% the pump is going to want to run again. So something has to toggle. So now coming to mind is a Flip Flop along with the XOR. I'm sure we can figure all that out. Or even recommend a purchased solution. But that's not what the TS has asked for. So are we limited by the question? Or are we at liberty to explore and suggest alternatives? I see no problem in recommending an alternative. But that means the TS spending money.
 

zophas

Joined Jul 16, 2021
165
This thread is typical of many threads on AAC. TS asks a question, regulars jump in with suggestions, TS is never seen again. Thread becomes dormant.
 

Reloadron

Joined Jan 15, 2015
6,684
This thread is typical of many threads on AAC. TS asks a question, regulars jump in with suggestions, TS is never seen again. Thread becomes dormant.
That would be true and in many cases like this one the thread starter fails to provide a full scope of the project. It's all in the details which are missing. :) Generic questions get generic answers.

Ron
 

Tonyr1084

Joined Sep 24, 2015
6,966
I've been suspecting the same thing. However, there have been times I've started a thread and then couldn't get back to it for a few days. Here it is Wednesday morning and the thread was started Monday morning. Two days and it could be that he/she hasn't had a chance to get back. The TS has been a member since November 2013, so they've been a member for a while, though records show they have only posted one posting. I suspect some people may delete their posts after a while. Or for whatever reason their posts and/or comments go away.
 

zophas

Joined Jul 16, 2021
165
What I really hate is when the TS is interested for awhile, provides feedback and everything but then disappears just when the problem is almost solved.
 

MisterBill2

Joined Jan 23, 2018
12,385
That's a good point. I hadn't considered that part of it. But I can also see an enclosed system where you can remove the lid to service the switch and float.

Yeah, that might work. However, that device is driving an LED to indicate the level. While it may be 5V (which we don't know) it might not be strong enough to trigger a relay. But I don't see how the pump would be controlled. When the water is below a certain level - lets say the bottom LED only - what's going to tell the pump to come on and run? OK, assuming that part is solved, when the tank gets at or near 100% full, how do you shut the pump off? I realize those are easy enough questions for us to answer, but what skill level does the TS possess to where he (or she) can build such a circuit? First thought that comes to MY mind is an XOR gate (or XNOR) But then as soon as you fall below 100% the pump is going to want to run again. So something has to toggle. So now coming to mind is a Flip Flop along with the XOR. I'm sure we can figure all that out. Or even recommend a purchased solution. But that's not what the TS has asked for. So are we limited by the question? Or are we at liberty to explore and suggest alternatives? I see no problem in recommending an alternative. But that means the TS spending money.
I described in minute detail how a pump would be controlled, back at post #4. Every single connection. The lower level detector energises the motor control relay, which stays latched until the upper level detector opens and releases the relay. With the LED device it would need a normally closed relay to operate and release the latched pump control relay. I have used that scheme in various machines perhaps a hundred times over the years.
 
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