I am developing a sensor based on the principle of EIT (Electrical Impedance Tomography).
For the project, I need to inject into the material I am using, a constant current between two electrodes placed at the periphery of the sensor and then read the corresponding voltages at the other electrodes (I have 16 electrodes). Then the current has to be switched between the remainig electrode pairs in a scanning cycle (as you can see in the picture-only 8 electrodes in the picture).
I am using 2 demultiplexer with 16 outputs to control the current injection. One multiplexer serves to control the current source and the other one for the ground in order to switch all the electrodes between ground and current source.
The MUX are controlled by the digital outputs of a NI DAQ-6353 card which also serves for reading the voltages in a differential mode.(you can see it in the schematic)
The circuit is powered with 5V and the resistance of the sensor is around 60K Ohm.
I am using a 10uA constant current. The power source will be external, as my DAQ can only supply 5mA and I will need to change the current amplitude in the future.
My question is this: is the circuit going to work? I don't see any problem, I have also tested the constant current generator and it works up to a load of 100K, but maybe someone with a more expert eye could see if there are some errors.