Inside the user guide we can find things such as the minimum current, input impedance, sourcing, sensor, and sinking. Many info such as minimum current requirement, proximity, interfacing, proximity sensors, and the leakage current are described in the user guide.
This user guide contains explanation like current sourcing, electromechanical, plc, proximity sensor, and sensors. Here are taken from this user guide:
If the input will not turn OFF, the leakage CURRENT SOURCING CURRENT SINKING POWER SUPPLY + – Connecting an input to source voltage will toggle the input. If the voltage produced by leakage current, times the internal resistance, when subtracted from the supply voltage, doesn’t produce a voltage high enough to allow the input to turn OFF, the input will remain in the ON state. Determining if an input is current sourcing or current sinking The determination of whether an input operates on a current sourcing or current sinking condition can be made by attaching a wire to the input and touching the other end of the wire alternately to ground and to positive.
Even more, this user guide explains information about current sinking, current requirement, the plc input, and the voltage drop.