If you use 4-20mA or 1-5V output sensors, the sensor itself will normally tell you any faults it recognize itself.
This is done either by putting out less than 4mA/1V or more than 20mA/5V.
An unconnected sensor will be 0mA/0V.
A short circuited sensor will be less clear, either a high current or 0V. If the high current is possible in your system you should protect against it, or it will blow your sense resistor.
A reversed sensor should be possible to detect with an extra detection circuit, on a digital input. You will anyway need some conditional circuit before the ADC for the mA input.