Frequency measurement with Fieldpoint

[mvitor]

Hi...

I am trying to develop an interface to read the wind speed from an anemometer, but the more I try to find an example to guide me to the solution the more frustrated I get...

I tryed to follow the example "Frequency_Measurement_(CTR).vi" and I did some modifications to reach my needs and I think they should not damage the vi.

Every thing seems to be fine, but when I run the vi and even if the anemometer is stoped I get frequency values, and if it's stoped its supposed to be 0Hz. I dont know what kind of support NI can give-me in a situation like this, but I am really scared.

In my mind, if I get to extract the frequency will be very easy to calculate the windspeed, for this I would like to use my FP-CRT-502.

All comments would be helpfull,

Regards,

Marcio

WS=N/47,6
where:
ws=windspeed in m/s
N=rpm
47,6 is the constant of the anemometer

[ChristopheS.]

Hi Marcio,

When you run your VI, and read the speed of the anemometer, is the value good or wrong ? One test for see if we make a good measurement is to connect a frequency generator.

When you stop the anenometer, are you sure that we have any pulse ? Try to make the measurement without the anenometer connected.

In your diagramme, place an indicator at the ouput of your "Read count" to see the value of the FP-CTR-502.

In the "False case", why do you reset the counter 1 ? If you use the counter 0, you need reset counter 0 for have the new value.

Let me know if you have question,

regards,

[mvitor]

In fact I did not chage nothing in the NI example. I dont understant your questions about the reset. It is as the example.

Disconecting the anemometer from the CTR module I still get frequencies. Its realy very strange.

It's a bad situation, we spend a lot of money in this equipment and in this software that was supposed to be easy to use. I realy dont know what to do. Give up maybe... and ask my money back??

Its incredible but almost all the examples I get from this site dont work for me. I tryed the "Low_Frequency_Measurement_CTR_LV71.vi" and I get the same problem.