?How to know what is the flow rate of a flow rate water sensor

Hey, Its the first time so angry comments please :slight_smile:
I got myself a fl-s401a flow rate sensor and I dont see in any place the flow rate.
I checked and it does about 26 rotations per second
I will be happy if someone can say to my solution
Here are the specs:

Frequency: F=98 * Q (L / Min), error: ± 2%
Flow range:0.3-6L/min
Suitable for 1/4" tube
Maximum Consumption current:10 mA(DC 5V)
Working voltage range:DC 5-18 V
Operating Temp:0-80 ℃
Operating humidity:35%-90%RH
Pressure range: 0-0.8MPa Storage Temperature:-25-80C
Storage humidity:25%-95%RH
Output Waveform:Square Wave,output pulse singal.
ROHS Compliant.
Cable length:15cm

  • Pressure range: ≤0.8MPa

appears to be a clue

1 Like

Yes, but if I just multiply it by 98 it is like 150 l/min

Multiply? What is "it"? Show your work (the math)...how do you get Q from F=98*Q? And, what (approximate) flow rate are you expecting to be associated with 26 rotations/sec?

When I look for a fl-s401 the search returns a flame sensor, not a flow meter. That is why it is important to post links to technical information on all the hardware devices you use. At this point I cannot help.

PS: judging from comments on Amazon for a similar product, your Amazon/Banggood/whatever formula may be wrong, and you may have to do your own calibration...never a bad thing to do, BTW.

It is refered to the 26 rps
I just took the rps and multiply it by 98

Why did you multiply the frequency by 98?

To be honset idk
I though it might work

Can you explain F = 98 x Q

Thats the problem, idk what it is
I posted this cause I thought some will know

So you look at this from the specs you quoted...

...and think that multiplying F by 98 will give you Q? Doesn't that...look...wrong? It is wrong.

Given that F is frequency (presumably pulses per second), and Q is flowrate (liters per minute), wouldn't you have 26 = 98 x Q

Do you know how to solve that for Q?

If you don't know enough algebra to solve for Q, check out the "one-step multiplication equation" tutorial here: https://www.khanacademy.org/math/algebra-basics/alg-basics-linear-equations-and-inequalities And if that's too deep, try some of the preceding tutorials.

Also, if you know your flowrate, Q, even if only approximately, what frequency does F = 98 x Q give you?

Thanks you very much! I will try and report the results :slight_smile:


Frequency: F=98 * Q (L / Min)

To solve for Q. Divide both sides by 98.

F/98 = (98*Q)/98

F/98 = (~~98~~*Q)/~~98~~

F/98 = Q

Q = F/98

:+1: :+1: :+1:

Tom.. :grinning: :+1: :coffee: :australia:


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