Voltage measurement DAQ

[Jonahvdm11]

I am measuring voltage output of a piezoelectric sensor. I expected voltage to be zero before applying pressure to the sensor. Does anyone know if this can be caused by the DAQ system?

Also every voltage peak increases compared to the peak before, could this be a characteristic of the measuring equipment? Otherwise this gives interesting information on the sensor itself.

Thanks in advance,

Jonah

[santo_13]

DAQ inputs do have some offset, you can measure this by shorting the DAQ input to GND.

What DAQ are you using? and what Piezo transducer?

[Jonahvdm11]

Hi,

Thanks for the quick response, I am using the USB-6289,

The sensor is self-made, a cell-scale univert is used to apply pressure.

thank you

[santo_13]

What would be the output impedance of your sensor? for any DAQ, the input signal should have the least output impedance possible to reduce the settling time.

This is an excellent read - https://www.ni.com/en-us/support/documentation/supplemental/06/is-your-data-inaccurate-because-of-in...

[Jonahvdm11]

Thank you for the article, 

I am not sure at this moment what the impedance is, I will try to find out when I am in the lab again.

My measurement in this case is around 120 seconds, could the settling time be this long or longer than this?