Strain Gauge Setup

[gmh265]

Hello Everyone..

I would like to use a few strain gauges to measure applied load to some steering/suspension components and it has been a long time since I played with a Wheatstone bridge

I have done a little research today and have come up with this..

Strain Gauges compensated for mild steel, that have 120 ohm resistance, hooked up into a quarter bridge with the other 3 resistors also being 120 ohm. I can use an 8 volt
excitation voltage with the logger I have (Motec ADL) and can also zero the bridge through the software.

I also have a rig that allows me to load up the test components to a set load to calibrate the logger.

Is there an IC that has signal filtering / amplification for this type of application?

Should I be using the 2 wire or 3 wire method for wiring up the bridge?

or am I just going about this the wrong was completely?

I am trying not to spend too much money on this one if that makes any difference.

Thanks

Joel

 

[bill318]

Hi Joel,

Maybe you have already found answers to your questions...

If not, the bridge typically has two excitation terminals and two measurement terminals. Excitation is usually DC but can sometimes be pulsed for an AC coupled amplifier.

The measurement terminals are typically connected to a differential amplifier. There are indeed special differential ICs designed just for these types of bridges if you want to go that route.

I'm not familiar with your logger so perhaps it has all the necessary circuitry in place.

See if you can find applications notes for the specific strain guages you have, they should be able to fill in the blanks for you.

Bill

 

[felixc]

You are going to get a voltage span in the range of 20 millivolts. Can your logger handle such low voltages in differential mode?