pulse width measurement

[29071985]

dear all!

Now, i am using PCI 6052E and labVIEW2010

i want to measurement pulse width (duration) of sound wave (get from ultrasonic sensor SRF05)

can u help me to make a program do that (use DAQmx)!

thanks so much!

[Yogesh_Redemptor]

I am not sure about this measurement.

But you can check the functions listed in following example.

C:\Program Files\National Instruments\LabVIEW 2010\examples\DAQmx\Control\Control.llb\PWM-Counter Output.vi

Regards,

Yogesh Redemptor

[johnsold]

With an ultrasound sensor you may be getting a waveform with a sinusoidal signal at the ultrasonic transducer resonant frequency and varying amplitude. Defining exactly what you mean by "pulse width" in such a situation is critical to making your measurement.  Are you concerned about the envelope of the waveform or the individual cycles of the ultrasonic signal? How noisy is the signal? Do you get multiple reflections, particularly overlapping pulses?

Please post a VI or image showing the data along with indications of the points which define the pulse width you want to measure.

Lynn

[29071985]

Hii Yogesh!

i try to use that program u told me! bút that not may research! i so sorry!

i had ultrasound sensor, send signal to taget and recieved signal back! i want to meassurement pulse width (pulse duration) of that signal!

but i did not know how to make a program!

help me!

[29071985]

Dear Johnsold!

i can show you 3 pic! about my program and some result i got! bút i thinks that were wrong! u can see,

can u help me!

first one is my program!

Second is my purpose, i want to measurement from the first cycle to second one!

last one is my result, but so big, over 700s ( i thinks minisecond or microsecond is ok)

can u help me! make another program do that! thanks so much!

this is the first time i used Labview and my English not good enough, i am so sorry!

[29071985]

hii Johnsold!

i am so sorry!

this is my image! thanks

[johnsold]

That certainly does not look like what I would expect to see from an ultrasonic transducer.

What is the resonant frequency of the transducer?

What is your sampling rate? Where do you set the sampling rate?

OK. I searched for your transducer and see that it has built-in signal conditioning so that you get a logic signal rather than the raw ultrasound.

Are you trying to measure the time between the trigger pulse and the echo pulse or the duration of the echo pulse?

I think you will be better off using the counters on your DAQ board than analog input.

Lynn

[29071985]

Dear Johnsold!

i am using ultrasound sensor SRF05, this is manual, u can see! http://www.robot-electronics.co.uk/htm/srf05tech.htm

pulse width depend the distance from sensor to taget! (distance is my new purpose when i finish measuremant pulse width)

u see manual, u can understand why we have that type of signal!

but i don't know, why i can not have correct signal!

help me!

[JÞB]

Well, First off stop creating and destroying DAQmx tasks in a loop. 
Create them once use them in a loop close them once.

Why did you toss out the dT information your measurment needs?  Wire the waveform into Pulse Measurements.vi instead of just the Y values and things should improve. 

I do not understand the scaleing you are applying after the pulse measurment.vi (But that should clean up when  you fix the waveform/Y values only bug)

[29071985]

Dear Jeff!

i try to make again my program! here!

i do not understand what u say! may be my English so bad or this is the first time i using LabVIEW!

Can u tell me more about that?

i show u new one!

thanks so much!