NI MAX Test Panel not reading any voltage from analog input (strain gauge)

[muralis]

Strain Guage: Transudcer Techniques Thin Beam Sensor-https://www.transducertechniques.com/tbs-load-cell.aspx

NIDAQ Board: NI USB-6251

I've been trying to get my strain gauge working with my board. When I hook up the multimeter to the strain gauge, I am able to measure the voltage difference when I bend the metal strip. So I know that my strain gague is working correctly.  

When I hook it up to the NIDAQ board and use a test panel from NI MAX on my computer to check it, I read a consistent 10.6 Volts regardless of how much I bend the metal strip. I even checked the NIDAQ board by connecting it to a voltage generator. If I vary the voltage on the generator, it shows on the test panel. But when I connect it to the strain gauge, the voltage does not change.

Basically, I know the strain gauge is working and I know the Board is working. But when I combine the two, they stop working. Do you know what's going on with this, or any potential steps I can take to fix this issue?

[GreyGrey]

It sounds like it may be due to the way you are hooking them up together. How are you connecting them?

I assume that your strain gauge sends analog voltage to the board. Are you using a BNC cable to connect the DAQ device? Are you using the same cable to connect the two in your test setups as well as the final setup? Are you sure that the cable you’re using to connect the two is functioning properly?

[muralis]

I am using the saem BNC cables during the final test and the initial two test setups. I even read the analog voltage at the pins on the NIDAQ Board, which were correct. Basically something is happening when the signal gets sent to the computer but only when I use my strain gauge. DO you have any other ideas of what could be wrong?

[GreyGrey]

Do the voltage range of the DAQ and the sensor match? What is the voltage output range of your strain gauge sensor?

[muralis]

The manual for the board lsits the Input range to be ±10 V, ±5 V, ±2 V, ±1 V, ±0.5 V, ±0.2 V, ±0.1 V. My Strain gauge is outputting ±10 V, as it should be.

[GreyGrey]

Can you post some pictures of your setup? Both of the two tests and one of the final setup where it's reading incorrecty.

Are you sure that you're grounding the signal coming from the strain gauge correctly? Not grounding it could produce erroneous voltages like you are seeing. 

[Hatef.fouladi]

the problem is that you use 16 bit daq best daq for strain gauge is 24 bit because
this sensor working voltage is not good range for daq under 24 bit
so for solving this problem you have to use driver for voltage amplifying
so your last answer is find a way for signal conditioning

[muralis]

hey guys,

I can post pictures tomorrow. What exactly do you mean by grounding the strain gauge? 

Also, how do I go about doing signal conitioning with this NIDAQ board? Or do I need to use a different DAQ?

Again, thank you for all the help!

[muralis]

I finally got the voltages to change when I deflect the strain guage with my hand! Hoever, the voltage still srops to 10.6 volts first. I am not quite sure why it does. When I try to zero it using my conditioning block, the read voltage refuses to budge. It flatlines at 10.6 Volts. Here are some pictures.

This is the strain gauge, a Transducer Techniques Thin Beam Sensor. 

This is the conditioning block that it is attached to. The BNC Cable is coming out the top right and goes to the NIDAQ Board.

Here is the board. The BNC Cable goes to the top left, to pins 1 and 3. This connects to my laptop with a standard USB Cable.

Here is a screenshot of my test panel. I deflected the strain guge four times, each stronger than before, which can be seen in the voltage difference peaks. However, as you can see the zero is at 10.6 V. What can I do to fix that?

Thank you!

[GreyGrey]

What do the cables at the bottom of your conditioning block plug into? Was that conditioning block used in the initial tests that you ran or is this an addition that you've added that has helped you get the detection of the deflection by the strain gauge.?