vibration sensor gives no value after sometime

[royal1]

Hello

I am using NI PCI-6024E card for acquiring voltage using vibration sensor(KS80D).First when I start to  acquire values from Vibration sensor, it gives me data fbut after some reading it gives constant value from sensor.Then When i Reboot my computer and start to acquring the voltage it acquire again but same thing happen after some time it gives me constant value.I have attached two pictures for more understanding.I do not know what is the problem.It it problem with overloading or somthing else with sensor?Please give me solution about this problem

[Henrik_Volkers]

Looks like a floating source with no bias path.

With differential measurement, add a 1Meg resistor from AI- to AIGND.

[royal1]

Servus Henrik,

Vielen Dank for your advice. I would try it but before  that can you explain me a little bit more in detail about this problem or can you refer me some document regarding this problem because I am little bit new for this.

[Henrik_Volkers]

How to measure voltage

and the documentation to your DAQ card ...