ni-9237 for lvdt

[simon76]

Hi,

I have daq module of ni9237.

Can i use it to measure the AC type LVDT?

Also, can share info on sensitivity of LVDT of 0.7V/V, what is it mean?

I check the module ni-9237 spec which has excitation voltage of 2.5, 3.3, 5, or 10 V, so which excitation voltage is suitable to decide to use with?

thanks,

Simon

[Izzzzz]

Hi Simon, 

I wouldn't recommend the NI 9237 for measuring an AC LVDT since the module supplies a DC Voltage excitation, returns a Voltage Read/Voltage Excitation, and your sensor's ouput is outside the NI 9237's ±25 mV/V. I suspect the sensitivity means that you will get a .7V output for every volt of excitation you provide but providing the specifications sheet for your LVDT should assist in confirming this and the compatibility (or the lack) between the sensor and NI 9237.

Regards,

Izzy 

[simon76]

Hi lzzy,

i still haven't finalise type & model of lvdt using.

If dc lvdt, then i can used with ni-9237? how about AC LVDT, any recommendation of the signal conditioning unit ?

thanks,

Simon

[Izzzzz]

Hey Simon, 

For a DC LVDT, there are still some concerns with using the NI 9237 such as the above mentioned ratiometric return value, and the sensors output may fall outside the NI 9237's measurement range. You can check the data sheet for your sensor to see the output and compare it to the input voltage range of the NI 9237. I don't have a formal recommendation for a signal conditioning unit but the sensor vendor may be more knowledgeable on this matter. If you find a signal conditioning for the AC LVDT then measuring the output with a voltage module and scaling it to the desired units would be preferable.  

Regards, 

Izzy 

[simon76]

Hi lzzy,

I found this article http://www.ni.com/white-paper/3638/en/

Is the NI SCXI good enough to measure back the AC LVDT with electrical bandwidth of 20khz?

regards,

Simon