This is the best Instrumentation OpAmp, Great CMRR, ensure supply has no ripple and keep analog and digital grounds separate. Ri can be replaced with a trimpot and resistor to alter gain. Connect a preset ends to pins 1 and 8 and preset wiper to VCC for Offset Null when high gains are configured.
Instrumentation Amp - Op-Amp Designs
The Input zeners and diodes form a protective clamp for all voltages above VCC-VDD. If supply is changed to +12 -12 change zeners to 12V zeners. Use similar Zeners at output to protect Output from being zapped by over-voltages or high energy - voltage or frequency transients. Add plastic capacitors across Rf for damping AC operation or ripple. Also avoid floating inputs by providing a bias, till you connect it to a sensor; or you will see electrometer like effects.
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Vout = ( Vp - Vn ) * ( 2Rf + Ri) / Ri
This configuration is revered by people making weighing scales. It may also be called strain gauge measurements. From tiny Kitchen Scales to Weigh Bridges. A Cantilever having a small sticker like film epoxied/glued onto it, which happens to be a sensor. A metal film or strip whose resistance varies when stretched. Stress and strain are the words they use. In the early days, this technology was a closely guarded professional secret, Not anymore. Read more about it here, but remember only the toughest designers can design such systems.