Measuring Pulse width from Flowmeter.

[MsCEn]

Hello everyone;

Firstly, I am a relatively inexperienced LabVIEW user, so while I will do my best to provide all the necessary information, if something is missing or unclear, my apologies in advance.

So, I am working with micro oval gear flowmeter and I have SC-2345 Signal Conditioning Carrier which has 42-position, triple-row screw-terminal block for connecting to E/M Series DAQ device digital signals on it.

My main purpose is acquiring the data of a pulse from the fowmeter in the unit of seconds, and then with formulas making it L/s. (Flowmeter has 7000 pulse/sec. > basically (1/data)/7000 will do that.) (also yeah frequency is same but we are not going to use that.)

So I connected the flowmeter to PFI9 (Input Terminal) and tried to get data with using express>DAQ Assistant>Acquire Signals>Counter Input>Period> USB6259 (Mass Termination)> Ctr0 . And I didn't get the data related. Also tried all other measurement like pulse width, semi period etc. still all I get some sort of random data which does not change by flow rate but when I shut off the flowmeter, I don't get anything at all.

So what do I do wrong? I know it is pulse and not analog signal, I don't know that should I do something with NI-Max, I already handled sc-2345 in max. I don't have any idea, I would be so appriciated if you help me.

http://www.btflowmeter.com/en/flow-meter-products/positive-displacement-oval-gear-flow-meters-gearwh...

[GerdW]

Hi MsCEn,

if you would read the specsheet more carefully you would notice the device gives pulses/liter (as any other usual flowmeter)!

All you need to do is to count the pulses you get with a simple DAQmx pulse counter task.

Then take the difference between current pulse count and the count one second before: scale the result by 1l/7000s to get your flow value…

[MsCEn]

---

@GerdW wrote:

Hi MsCEn,

if you would read the specsheet more carefully you would notice the device gives pulses/liter (as any other usual flowmeter)!

All you need to do is to count the pulses you get with a simple DAQmx pulse counter task.

Then take the difference between current pulse count and the count one second before: scale the result by 1l/7000s to get your flow value…

---

Hi GerdW, thank you for your response.

Do you mean CounterInput>Pulse Measurement>Time by DAQmx pulse counter task. I tried to do frequency, just trying to see if that read anything, but still random things.

Also can you please tell more about taking the difference and scaling, It would be really good to see an example with VI, it is hard to get right with this way, I would really appriciate it.

[rleonard3]

Hi MsCEn,

There are some example VI's inside of LabVIEW that you can build on by going to Help -> Find Examples -> Hardware Input/Outpt -> DAQmx -> Counter Input. Could you post your VI to this forum? Thanks.