Accepted. But I think this will still work with signal conditioners that have thier own mains supply transformer and thus have "thier mV to mA " circuit ground floating with respect to the ADC ground which is ground 2 in Kai's circuit.

1) if I understand you correctly, you are saying thet what Kai label GND is not connected to ground. In that case, of course the line will float. However that would absolutotally kill the balance of the circuit in relation to noise etc since ine line would be connected to the transformer, rectifier return etc.
2) with the ground connection removed as I suggested in my previous post, the circuit will work.

Erik