3 inputs into 1 gain isolators go to a 1/3 Gain inverting amp on the 2nd stage. Finished off with a 1 gain inverter. The averaging is in the 2nd stage. If you want 2 input averaging, change the gain to 1/2. 4 input averaging, 1/4 gain on the 2nd stage.
Good for process signal conditioning. A 0-10 VDC process signal can be added to other 0-10 VDC signals and this circuit will keep the output at 0-10 VDC
