A 3-wire proximity sensor has three main connections — brown (positive supply), blue (ground), and black (signal output). When testing an Omron 3-wire proximity sensor, you can easily check if it’s working correctly using a multimeter or a simple test circuit. The goal is to verify that the sensor is receiving power and that the output signal changes when a metal target comes close to its sensing face.
To check it, first connect the brown wire to the positive terminal (+V) of a 12–24 V DC power supply and the blue wire to the negative terminal (0 V). Then, connect the black output wire to the positive terminal of a multimeter (set to DC voltage mode), and the other probe of the multimeter to the negative terminal. Now, bring a metal object slowly near the sensor’s sensing face. If it’s an NPN type sensor, the output should go low (0 V) when the object is detected. If it’s a PNP type sensor, the output should go high (close to supply voltage) when detection occurs. You’ll see this voltage change clearly on the multimeter display.
This simple test helps confirm that the Omron 3-wire proximity sensor is receiving power, responding properly to targets, and switching its output as expected. If no voltage change occurs, check the wiring, power source, or sensor polarity, since incorrect wiring can prevent the sensor from operating. Always ensure you test in a safe, low-voltage environment following the sensor’s datasheet specifications to avoid damage.