Regardless of PLC I have a programmed function that reads the analog inputs and detects under/overrange and under/overflow conditions. For sensors I disable these warnings/faults if the sensor isn't currently active (i.e. pump off).
However, I have this small system with 3 pressure sensors and 2 flowmeters controlled by a Siemens S7-1200 w/ 16-bit AI, and all sensors read negative when the system is switched off. All sensors are 4-20mA. Without thinking too deeply about it, I was initially thinking that the entire scale might be off or sensors not properly calibrated or something, and thought that shifting the entire scale slightly based on the zero point on each sensor would make sense. But I haven't tried to check the inputs with a meter or calibrator or anything. Maybe the measurement reference is shifted slightly to the internal ADC reference somehow? Would have to think about this some more.
Interesting idea regarding the calibration (applying max and min values to PLC and scaling based on that). You would have to have full control over the process variable then, and have to know that accurately, no? Or I could, for example, apply 4.000mA via an external circuit to the module and read the input. I suppose that would help eliminate module error, but not sensor error.