TL-Q5MC2 Photoelectric Sensor NPN NC, Unshielded, DC 10–30V, 5 mm Sensing Distance

The TL-Q5MC2 uses an NPN Normally Closed (NC) output. This means the output transistor is normally ON (conducting to ground), providing a low signal. When an object is detected within the 5 mm range, the transistor turns OFF, and the output signal goes high (open circuit). This is the opposite behavior of an NPN Normally Open (NO) sensor and is often used for fail-safe circuits where a broken wire or power loss results in an alarm state.

The sensor's NPN output transistor can sink up to 200mA. This is sufficient to directly drive small relays, PLC digital inputs, indicator LEDs, or buzzer modules. Always ensure the connected load's operating voltage matches your supply (10-30V DC) and does not exceed the 200mA current rating to avoid damaging the sensor's internal circuitry.

As a diffuse-reflective photoelectric sensor, the TL-Q5MC2 may have reduced reliability with highly transparent (like clear glass) or specularly reflective (like polished metal) objects. The sensor works by detecting light reflected from the target's surface. Transparent objects may not reflect sufficient light, while shiny surfaces can scatter the beam unpredictably. For such materials, a through-beam sensor configuration is recommended.

Connect the brown wire to your DC positive supply (10-30V), the blue wire to DC negative (GND), and the black wire is the NPN NC output. For a PLC input, connect the black wire to the PLC's digital input terminal. Since it's an NPN output, the PLC input common should be connected to positive voltage (sourcing input). For a microcontroller, you will need an external pull-up resistor (e.g., 10kΩ to 5V/3.3V) on the black wire to read the signal, as the output provides a switched ground.