Label Detection | Label Sensors | Working Principle of Full-Metal Label Sensors

With the growth of industrial automation and higher labeling speeds, labelers must evolve from manual or semi-automatic operation to high-speed automatic labeling. Common challenges include detecting special labels, preventing misfeeds and meeting accuracy and speed requirements.

The solution lies in the label sensor. Sensors act as the "eyes" of labeling systems. Due to diverse label materials and complex formats, label sensors must offer high accuracy and fast response. Common detection principles lead to different sensor types; slot-type through-beam housings are widely used. Based on principle, label sensors can be photoelectric, bipolar capacitive, single-electrode capacitive, or ultrasonic.

1. Photoelectric label sensors: use a slotted housing, light modulator, emitter LED, receiver, demodulator and PIC controller to form a threshold-based switching circuit. When the gap between labels passes through the slot the transmitted light exceeds a threshold and a switching output triggers the host. Atonm slot sensors are fast and suitable for paper labels. Representative product: LS1-NM12C full-metal label sensor.

Advantages of Atonm full-metal LS1 series label sensors

(1) 3 mm slot width and 60 mm slot depth for precise on-machine detection

(2) High switching frequency and very short response time for excellent repeatability

(3) Long-slot design allows label placement at slot edge for direct detection

(4) Adaptive logic (auto level control): auto-optimizes switching threshold for best performance

(5) Warning output, calibration display and error indicators

(6) Simple adjustment via calibration button or calibration output

2. Bipolar capacitive label sensors: use a differential capacitive detection circuit with two electrodes, ADC and PIC to cancel distance variation effects between label and electrode.

3. Single-electrode capacitive label sensors: use a single detection electrode, ADC and PIC; signals are amplified, compared and output as switching signals. Capacitive detection is stable and suitable for high-speed labeling.

4. Ultrasonic label sensors: use ultrasonic transducers, driver and PIC to form a through-beam detection system. Due to acoustic propagation time, these suit medium-speed labelers.

When a label reaches the sensor it sends a signal to the labeler controller or PLC, confirming position and preparing the next labeling event. Choose sensor type by label material; Atonm label sensors can detect standard and transparent labels without replacement.