No, like all standard digital PLC inputs, the E10-npn input trigger level is fixed and cannot be assigned to other values. Unless you put a low pass filter (a resistor and capacitor) to average out the voltage, the PWM signal you receive will trigger many ON/OFF actions in the PLC program, it will not take the average of the PWM. What is the peak voltage of the PWM signal?
A T100MD888+ with pulse width and pulse frequency measurement functions will be able to directly measure the input signal and perform the required actions effortlessly.