I've designed a circuit around the TI LMP91000, a configurable Analog Front End (amperometric potentiostat, for use with electro-chemical gas sensors). In addition the circuit includes a 2.5V reference (for VREF on the LMP91000), and an 18-bit ADC.
Once the sensor is installed in circuit, it's very difficult to remove it without doing harm. I've experienced a significant number of failures late in the testing process (e.g. during calibration), that I don't understand the root cause of yet, but which I suspect are related to undetected manufacturing defects in the underlying circuit (i.e. not a problem with the sensors themselves). The upstream testing that I do right now is limited to just establishing I2C communication with the LMP91000 and the ADC before installing the sensor. If I could identify problems earlier, I could potentially fix them before installing sensors.
Is there a way to temporarily attach an external circuit in place of the electro-chemical sensor (i.e. using pogo pins connected to the working, counter, and reference electrode inputs) to inspire the LMP91000 to output an expected voltage so that I can demonstrate the analog front end is working correctly before installing a sensor? What would the composition of such a circuit need to be?