strain measurment

[s.g.cabo]

hi

my project is to calculate the displacement or strain of cantilever beam by using a piezoelectric sensor, i am using DAQ 9215  to acquire signal .

i need to convert the voltage from the pzt  sensor to strain or displacement is their any way to do that in labview software 

[mikeporter]

Are you reading the sensor directly, or are is there a vendor supplied signal conditioner? If reading them directly, bear in mind that they are very, Very, VERY susceptible to noise. That sensor should come with a conversion factor in (I think) microstrain/V. It's been a few years since I have worked with them.

Mike...

[mikeporter]

Oh yes, what is your application?

Mike...

[Jacobson-ni]

To add to Mike's questions, are you using the 9215 in a cRIO or cDAQ chassis?  If you are using the 9215 in a cDAQ chassis and you find that there is a direct conversion from Volts to strain then you can use DAQmx scales.

http://digital.ni.com/public.nsf/allkb/0464919A11C092E386256D800079C3BB

But like Mike said, measuring strain can be very tricky sometimes so it would help to know what sensor and signal conditioning you are using.

[s.g.cabo]

 thanks for replay 

i bound the quickpack pzt  sensor to the  flexiable cantilever beam at the fixed end and i have pzt actuators at the fixed end but in the other side 

my application is  using pid controller ( active vibration control ) and i need to convert the voltage signal from the pzt sensor to strain or dispacement  

i have no problem about the control only i want to convert the pzt sensor signal to strain or dispacement 

[Tanner!]

I know the hardware setup seems irrelevant because you already have it working, but what hardware you're using determines what software tools are available to you.

You can either use a DAQmx task to convert from volts to strain, or the datasheet for your device will have a formula or curve you'll have to implement.