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### Topic: Flowmeter sensor (Read 7594 times)previous topic - next topic

#### doctor_t

#15
##### Jul 05, 2014, 02:53 pmLast Edit: Jul 05, 2014, 03:02 pm by doctor_t Reason: 1
looking at datasheet of this link

http://www.seeedstudio.com/wiki/File:G34_Flow_rate_to_frequency.jpg

if i get 11 hz as result i have 11,2 lt per minute

so in case i have 3320 rpm it means that i have a flow rate of 602 L/hour?

am i right?

#### Nick_Pyner

#16
##### Jul 05, 2014, 03:18 pm
You wouldn't know what the rpm is, and don't need to know either.  All you need to know is the pulses per litre, in this case 60, and any calc can be taken from there.

#### doctor_t

#17
##### Jul 05, 2014, 03:31 pm
and in the case of my sensor how many pulses/litre i should read?

#18
60

#### doctor_t

#19
##### Jul 05, 2014, 03:51 pm
and it is calculate with the function of NbTopsFan?

#### doctor_t

#20
##### Jul 05, 2014, 03:55 pm
i would like to understand better this forumla not to make further mistakes with other calculations

Calc = (NbTopsFan * 60 / 5.5); //(Pulse frequency x 60) / 5.5Q, = flow rate

NbTopsFan is number of turns arduino detects in determined time if i make delay of interrupt of 1 second it will calculate turns douring 1 second

60 is minute? 1 hour

and what is 5.5  i still don't understand and from where it comes from

#### Nick_Pyner

#21
##### Jul 05, 2014, 04:41 pm

i would like to understand better this forumla not to make further mistakes with other calculations

Calc = (NbTopsFan * 60 / 5.5);           <<<<<<<<< THIS is the formula

pulses per second * 60 = pulses per minute. Divide by pulses per litre to get litres per minute.
Quote

NbTopsFan is number of turns arduino detects in determined time if i make delay of interrupt of 1 second it will calculate turns douring 1 second

No. NbTopsFan is the number of pulses. - the "Pulse frequency" as clearly stated.
The 5.5 is the calibration (pulse/litre)

Quote
60 is minute? 1 hour

Either, neither, or both. You asked for pulses per litre. The time is irrelevant. I think you should ignore this anyway. It doesn't match with the formula.  I don't think the seed crowd know what they are doing. I have already posted Oxer's programme, he does know what he is doing, and properly explains it.

#### doctor_t

#22
##### Jul 05, 2014, 05:45 pm
So in case i use oxer programe should i change the value of calibration for 5.5 instead of 6.82?

#### Nick_Pyner

#23
##### Jul 05, 2014, 06:00 pm
Yes. The 6.82 is the factor I use for a turbine with 1/2" fittings.

#### doctor_t

#24
##### Jul 05, 2014, 06:11 pm
My sensor is 3/4 son should be that

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