Hi, I have question about counting pulses. I have a flow sensor which generates pulses through its impeller as liquid goes through it and makes it spin. I am supposed to get certain amount of liquid every certain amount of pulses. Most of the times it is fine (gives the right amount of liquid). But sometimes less liquid is obtained for the same amount of pulses (it's always less...never more).
I have checked the pulse counter and it is correctly cleared back to zero when pulse counter reaches its max. Could this have something to do temperature, micro's clock frequency, or it would be the flow sensor calibration?
Has anyone ever done anything like this and have the same problem? The apparatus is boxed and temperature inside the box is always 11 to 12 degrees higher than ambient temperature.
I will appreciate your comments

Thanks!