Hi all,
I've recently bought a copper water flow sensor from eBay. The description said that the calculation formula is the following:
F = 8.1 * Q - 6 [Hz]
I asked the seller what is the "- 6" exactly, because the other water flow sensors didn't mention any constants in the formula.
Of course, the seller had no idea what it is. It just does not make any sense. If the flow (Q) is 0, the F would be negative!
Do you guys know what it could mean? Any ideas?
Thanks!
Ummm, what are Q and F? For that matter, what sensor?
It is easy to calibrate a flow sensor yourself. Just let water flow through it into a bucket at some constant rate, monitoring the sensor output. The flow rate is the total volume divided by the time.
Q is the flow in Liter/hours. F is the frequency of the hall effect sensor. It generates square signal.
Unfortunately, the flow sensor is already built into the heating system so it would be hard to take it off to calibrate it.
you can rewrite the formula: F = 8.1 * Q - 6 <==> Q = (F+6)/8.1;
now the flow is a function of the frequency, never negative (but a leakage of almost 3/4 liter/minute for F==0)
Okay, so you are saying that the sensor is not raising any signal if the flow is lower than ~0.75 liter/min?
So it might be the propeller inside which is too heavy to move when there is a low water flow. That's the "-6" in the formula.
yes, that is an interpretation of the formula
if you have a datasheet you might be able to confirm.
Unfortunately I don't have any data sheet. Thanks for your help! I really appreciate it 