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Problem counter (Frequency)

Hi,

I have a DAQ card 6024E. I want to measure a frequency between 10 and 500Hz, (from a propeller) approximately. The signal come from a inductive-sensor. When I put the signal on the PFI9 input (ctr0 gate) and I use the DAQmx "CI Frequency" (1 counter measure) I get sometimes good measure and sometimes wrong measure (0,3 Hz or 2MHz for example).

So, Please you can help me, where is the problem?

Thanks

Franco

 

this is mi VI

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Problem counter is nice , I stopped counting them 😉

 

How does your sensor output signal look like?  Read it with a scope or your card (set at max sample rate) .

Then take a look into the spec of your card if the output match the counter input spec.

 

at least you can read the output with an analog channel ( add maybe some filter) and do a tone measurement.....

 

Greetings from Germany
Henrik

LV since v3.1

“ground” is a convenient fantasy

'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'


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Hello,

 

I already answered to your question on the french forum but I also answer here for english people who have the same problem.

 

There are a few problems in your VI. The detailed help specifies that you don't need to connect the divisor input when you choose Large Range with 2 Counters in the measurement method of DAQmx Create Channel (CI-Frequency). Moreover, you don't need the DAQmx Timing (Implicit) function in your VI. However, you'd better add a Wait Until Next ms Multiple in your while loops in order to avoid a processor overload which would slow down your computer.

 

So I changed a few things in your VI. Please find it in attachement. I saved him in LabVIEW 2009.

 

Please let us know if you succeed to read your frequency measurements.

 

Best regards,

Jérémy C.
NI France

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thank you very much, I sent you a message asking for the VI in labview2009, in the french forum, sorry

thanks


 

 

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