The current regulator is a bit unusual in that the supply current of the IC flows through the sense resistor and does not affect accuracy as long as it is less than the desired output current. It is also possible to use remote amplifiers with two-wire signal transmission, as was done with the comparators. Remote sensors can be particularly troublesome when low-level analog signals are involved. Transmission problems include induced noise, ground currents, shunting from cable capacitance, resistance drops and thermoelectric potentials. These problems can be largely eliminated by amplifying the signal at the source and altering impedances to levels more suitable for transmission. Here is a schematic drawing :
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