Hello, I'm making a loadcell amplifier board. Input from -18mVDC to +18mVDC. Output +-2.5V. Input signal frequency from 0 to 14Hz. I have made a design as the attach. The total gain changes from about 140 to 50 according to real condition.
- First, I don't know why the output is very fluctuated and gaining is wrong.
- Second, I intend changing the low-pass filter to pre-amp + filter. The IA will became to post-amp.
Anyone help me what is the wrong in my design and how to solve it.