Module with isolated analogue inputs having low leakage current

A module with isolated analog inputs for use with a programmable controller, comprising:

• a plurality of input pathways that are each isolated by at least one respective of optical isolation static relays controlled selectively by a first controller, wherein each pathway passes a respective signal;
• a multiplexer including a plurality of channels including one respective channel for each of the plurality of input pathways, that each include a respective breaker controlled by a second controller to open or to close, wherein each respective channel of the multiplexer receives a respective signal passing on a respective of the pathways, and outputs a selected of the received signals, and the second controller controlling the multiplexer is coupled to the first controller controlling the optical isolation static relays so as to synchronize opening/closing of the plurality of input pathways, by controlling the respective plural isolation static relays, with opening/closing of a respective channel of the multiplexer, the multiplexer further including at least one channel employed to carry out an autocalibration including a channel routing a voltage reference, and the multiplexer further configured to short-circuit its input, for the autocalibration;
• and
• an analog-digital converter connected to an output of the multiplexer, wherein the analog-digital converter receives the selected signal output from the multiplexer.