I am working with a standard quarter-bridge strain gauge signal conditioning circuit. My excitation voltage is 5V DC, and my resistors are 350 ohm. I am amplifying the signal with an AD620 in-amp. I cannot get clean data, presumably due to all of the noise sources. I am using a load frame that is powered by a massive hydraulic unit that is accompanied by an even more massive transformer, several UPS's, control boxes, digital controllers, etc. Relocating the signal conditioning circuit is not a practical option.
What is the best method of attenuating the noise in the circuit? I am assuming a lowpass filter (or several lowpass filters). I have also heard of driving the reference on the in-amp with an op-amp (I have some LF412s) or a shunt voltage reference (I have a few LM4040s) to get a cleaner reference. Any suggestions or circuit diagrams would be greatly appreciated, since I have no electronic background (I am a civil engineering graduate student working on instrumentation for my thesis).
Also, if I use a lowpass filter, what cutoff frequency should I aim for? I am assuming since my signal is DC, I should be aiming for as low as possible, but I could be misguided.
Thanks in advance!
What is the best method of attenuating the noise in the circuit? I am assuming a lowpass filter (or several lowpass filters). I have also heard of driving the reference on the in-amp with an op-amp (I have some LF412s) or a shunt voltage reference (I have a few LM4040s) to get a cleaner reference. Any suggestions or circuit diagrams would be greatly appreciated, since I have no electronic background (I am a civil engineering graduate student working on instrumentation for my thesis).
Also, if I use a lowpass filter, what cutoff frequency should I aim for? I am assuming since my signal is DC, I should be aiming for as low as possible, but I could be misguided.
Thanks in advance!