The analogue interface is designed for a 0-20mA current loop. Connect either an active or passive current loop sensor as follows (active current loop sensor, connect positive to positive, and negative to negative):
The passive current loop sensor will need a power supply to power the loop (typically the voltage is determined by the ratings of the passive sensor), in this form the AKKR8 sensor can be on the low-side or high-side as seems best, but the positive pin must feed current INTO the unit, and the negative pin will provide the current OUT OF the unit.
The GPIO in the sensor can be used to power up a sensor as well, this is very useful in situations where the device should save energy as the sensor will power up the analogue sensor only when it should be used. This programming is done before delivery, please refer to the following wiring diagram: