I'm trying to find alternate economic way to test performance of strain gauge circuit (attached below) over resolution below 1mV. So far, I have tested it for 1mV differential inputs at Instrumentation Amplifier's input with help of Freescale Kit DAC's output.DAC output was fed into inputs of INA ( Instrumentation Amplifier ) to check its performance at a high level.
Up to what order or range of input signals do you want to test?
So far I have been able to test with differential input 1milli volt.If I could go anythign beyond this range say 10^(-4)V or beyond resolution would help me gauge performance of instrumentation amplifier.
Testing the DAC may not be the best method to test small-signal performance, because the performance is limited by the DNL and zero/offset errors of the converter. It would be better to attenuate.
Here's what we would recommend instead: if you have a lab power supply available, shift the supply voltage or the DAC supplies to +/-1.65V. If the REF pin is not derived from the supplies, it will also need to be shifted down by 1.65V. Use a resistor to attenuate the output of the DC source or the DAC by at least the same as the gain of the AD8237, so you don't have to source such small voltages directly. For example, you could divide by 1000 so that 1V from the source corresponds to 1mV at the AD8237 input. This way, the noise, offset and DNL errors are minimized.
It is also recommended that you consider the output resistance of the bridge that you will be using. Say for example you plan on using a 10k bridge, you could ground IN- through a 5k resistor and source IN+ through a divider that has an output impedance of 5k.
I hope this helps!
There is possibility to install strain gauge adhesive without any glue?
Unlikely - strain gauges are incredibly sensitive, and if they're not mounted properly, you'll have no idea whether drift / errors are due to the strain gauge or your circuit. See Jim Williams comment, note 2, page 36 of AN43: https://www.analog.com/media/en/technical-documentation/application-notes/an43f.pdf