Use 6215 to give excitation voltage and analog input with pressure sensor?

[MechHead]

I am currently doing a project where I will be using an NI 6215 to measure pressure with a Tekscan Flexiforce sensor.  I know I will be measuring the output voltage, which is relative to the pressure on the sensor.  What I would like to do though, is to hook the sensor directly up to the 6215, without making a circuit like the one below.  I have tested the sensor in MAX, and I can get it to show me pressing on the sensor, but without a the recommended circuit below, I get a lot of noise - essentialy as soon as I hit the sensor pad my voltage drops to 0. 

What I would like to know from anyone that has used these or similar sensors.  Is there a way I can hook up this type of sensor directly to the 6215 and use the +5 voltage, AI ground, and an AI channel to measure the voltage output of the sensor?   I would like to have a very simplistic Labview program to do so (version 7.1) that I can use DAQ-mx for, to get my output voltage from the sensor and then get my output in pressure by plugging the voltage through an equaton (I will calibrate a curve to get the equation, as I have done before).  I've always used Traditional DAQ stuff until now, and would like to learn the DAQ-mx stuff.  Any examples besides the ones that Labview itself provides could also be helpful.  Any help is greatly appreciated!

[MechHead]

Anyone?

[MechHead]

Ok... I can get the sensor to show voltage in MAX by hooking it up straight to a AI channel.   The signal starts at -5-7 volts and drops to -10 very easily if I touch it at all.  So the sensor is very touchy, but the signal makes sense at least.

Whe I try to do anything with a DAQ-MAX example I cannot get anything to show up on the graph at all.  Why will the measurement and automation explorer show it, but not a DAQ-MAX example?

[Deborah_B]

Hi MechHead,

Adding the recommended circuit will greatly help your signal, hence the op amp. Also, be sure you have a Differential input selected, that will help minimize noise. Here's an article to help the transition from Traditional DAQ to DAQmx in LabVIEW. Running a search on our internal database I'm not finding any customers using this sensor. Which DAQmx example are you running, and what are your NI-DAQ and NI-DAQmx driver versions?

Thank you,

Deborah Y.