Period_Measurement_With_CTR_50x.vi does not workf

[mvitor]

I am trying to program a CTR module following the example Period_Measurement_With_CTR_50x.vi but have no sucess.
All that I get is the flashing light from the Fieldpoint module anb the flashing light at the VI but the graphic has no value, I mean, no amplitud.
I am using an anemometer to the input signal at Gate 0 (pin 9 + pin 22)
The value that I get is 0,000093750000000000002 even when it is stoped.
I am trying to configure this strange software since december 2005 but until now I have no luck.
The max rpm for my anemometer is 2750RPM, each period of 0,021818181818181818181818181818182s
Is there any body available to help me?

[kamalb]

Hi
Can you send me your code? Do you want to recover the register of the counter each time your source is on +5V??

Kamal
NIF

[mvitor]

Here is the code I used. I did not understand your 5 volts question.

We are usign a Vector Instruments A100R anemometer.

Regards

[kamalb]

Hi
What do you want to do exactly, i do not have understood everything sorry??
Do you have configure and test your fieldpoint in MAX?? Are you using a counter module?? What are you connecting to the source and the gate????

Kamal
NIF

[mvitor]

Hi Kamal,

We want to measure the wind speed inside a wind tunnel using a 3-cup rotor type anemometer.

For each complete rotation of the anemometer we have one pulse, if we get 425 RMP, for instance, we should read 9,04 m/s.

Yes.... I have configured the FP-CTR-500/502 Field Point module in MAX according to the example instructions... a lot of times...  🙂

I have made some modifications on the initial VI to meet my needs.

I am connecting the anemometer to the gate (I think its strange too), according to the intructions at the example too...

"5. Wire the signal to be measured to Gate 0 (pin 9)."

Thank you for your attention.... any help would be very usefull.

[kamalb]

Hi
I don't have understood why you connect your anenometer to the gate.
The source permits to up the counter register and the gate is like a trigger for the ttl signal of the source...


KAmal
NIF

[mvitor]

I realy dont understand this gate stuf... the most incredible is that this is an instruction included in the NI example, isn't it? Or is this a English interpretation matter?

In the step 5, iten number 5 you can read: "5. Wire the signal to be measured to Gate 0 (pin 9)." It seems that does not make sense for you. I confess that my knowledge about LabView is very poor and if you think there is a better way to do this feel free to give your opinion.

I think that this NI example is just to let us crazy... 🙂 

The most incredible is that I am trying too to follow an other example and does not work too.

Measuring Low Frequencies with LabVIEW and FieldPoint Using [c]FP-CTR-500/502

This seems to be a more inteligent VI because the indication is to connect the signal to Channel 0, but using this VI we get frequency and period values even if the channel is opened, I mean, without connect the anemometer I have strange values indication.

I consider 45Hz a low frequency... dont you agree with me?

I am using LavView 8.0, but I think this should not be a problem. Correct?

Regards,

MV

[kamalb]

Hi

Typically the method i use to measure the frequence is the following:
I connect to the gate the signal i want to measure. The source is a timebase of known frequencies (example 100 khz)

If i have X counts for a period of the gate, the period is:

pulse period=X*1/100000

kamal
NIF 

[mvitor]

Thank you Kamal, but this is the part I understand. My main problem is know if the VI is good or not to do what we need.