Re : 9215

[SamuelC]

I have a cDAQ system with NI 9215 module. My intention is measure the force using a force sensor (http://www.tekscan.com/flexiforce/specs-flexiforce.html), I’m not a specialist in data acquisition system but I want to known if is it possible measure force with this kind of sensor? Because I was trying measure how the voltage varying if I applied force in the sensor, and obtained the following results:
1: If I do not applied any kind of force the variation of the voltage are like sinusoidal as ~ 0 value as a minimum and 200mV as a maximum.

2: If I applied load the voltage tend to reduce the amplitude value, but maintain the sinusoidal form (~0 to 10 mV).

I connected directly the force sensor to the screw terminal of 9215 without any signal conditioner. And I use signal express to make that (Terminal configuration: Differential, Scaling Unit: Volts)

The connection that I use is correct? Or I need any conditioner? Like a resistors

Thanks and have a nice day

SamuelC

[Wilfried_71]

I think it must work without any conditionner : you need to plug a power supply of 5 V between the ground and Vt, then you plug the ai0+ of the 9215 card on the Vout and the ai0- on the ground. The voltage you measure is not significant, so maybe you must adjust the Rf resistor to increase the Vout ?

[ibecerra]

Hi everybody.

In the datasheet that you showed us, there comes a recommended circuit for the signal conditioning:

http://www.tekscan.com/flexiforce/samplecircuit.html

You will find that your sensor gives you resistance so you have to convert it to voltage so your 9215 can read it. With that recommended circuit you will have the next voltage response at V(out) terminal of the recommended circuit:

http://www.tekscan.com/flexiforce/flexiforce.html

I hope these helps.

Israel B.

AE Mexico.