Fiber Optic Sensor Color Adjustment

Adjusting a color fiber optic sensor involves proper mounting, selecting the correct LED color, teaching the reference color, and fine-tuning sensitivity and output settings for reliable detection.

Mounting and Installation

Before adjustment, ensure the sensor is physically installed correctly. Mount the sensing head at a consistent distance from the target, typically 10–50 mm, using a bracket that minimizes vibration. The sensor should be perpendicular to the material path to avoid angular reflections. For transparent or glossy surfaces, consider a polarized sensor to reduce glare. Shield the sensor from direct sunlight or strong artificial light to prevent interference with detection .

LED Color Selection

Color fiber optic sensors often use RGB LEDs. Choose the LED color that maximizes contrast between the mark and the background:

• Red: Black mark on white background
• Green: Green mark on red background
• Blue: Yellow or white mark on dark surfaces Cycle through the LED options while observing the sensor's output indicator. A steady ON signal when the mark is present indicates the correct color. Some sensors allow automatic color selection via a teach button .

Teaching the Reference Color

1. Place the target color mark under the sensor lens.
2. Press and hold the teach button for the duration specified in the manual (commonly 3 seconds).
3. The sensor samples the color and stores it as the reference.
4. For marks similar to the background, use a two-point teach: first teach the mark, then the background to set a threshold .

Sensitivity Adjustment

Adjust the sensitivity potentiometer if available:

• Turn clockwise to increase sensitivity for detecting subtle color differences.
• Turn counterclockwise to reduce false triggers from background variations. For high-speed applications, set a short output delay (1–5 ms) to avoid missed detections. For slower materials, a longer delay (10–50 ms) can filter noise .

Output Configuration

Connect the sensor to your control system using the appropriate output type (NPN, PNP, or analog) to match your PLC input. Some sensors allow inverting the output or delaying the output timing to suit your application .

Verification

After adjustment, verify the sensor's performance:

• Ensure it triggers only on the target color.
• Use an oscilloscope if necessary to check output pulse width and timing.
• Re-adjust sensitivity or LED color if false triggers occur . By following these steps, your color fiber optic sensor will reliably detect the intended marks while minimizing false signals and production downtime.