Color Sensor Applications on Industrial Production Lines

Under the "Industry 4.0" intelligent manufacturing trend, automated sorting by color is increasingly common on production lines, replacing manual, repetitive sorting tasks.

Most conveyor-line items are relatively consistent and color variations are small. With controllable object speed, a Color Sensor can be used to identify colors. A PLC then drives a robot to sort items according to configured logic.

(Robot sorting system diagram)

Color recognition sensor system principle

The system detects item colors using sensors and sorts items by color. It supports continuous, high-volume sorting with low error rates. Items on the conveyor may be a random mix of red, yellow, blue and green.

Atonm CL2 Color Sensor can detect red, yellow, blue and green. When the sensor recognizes red matching the taught color, it outputs signal 1 (red) to the PLC; the PLC commands the robot to move the red item to conveyor 1. The same logic applies for yellow, blue and green to conveyors 2–4.

Control process of the color recognition system

❖ Robot home position: the robot stays centered, retracts, rises and releases pneumatic fingers;

❖ When the system is stopped and at home, press Start to begin robot operation;

❖ If the Color Sensor does not detect a taught color, the system waits; if waiting exceeds 15 s an alarm sounds. When an item is detected, the alarm stops and the robot acts.

❖ Robot motion: extend, lower, clamp, lift, rotate to angle based on the CL2 channel signal, descend until a limit switch is triggered, release, rise and return to transfer position. If transfer completes, the arm retracts to home.

❖ PLC receives color sensor signal 1 (red) and directs the robot to place the part at position 1 (conveyor 1); signal 2 (yellow) directs to position 2, and so on for channels 3 and 4.

❖ The system supports single-cycle, continuous, step and manual modes. Single-cycle handles one part transfer; continuous mode transfers parts repeatedly; step mode is used for debugging and process verification; manual mode performs one robot action per button press via interlocks.

Robot starts from home position.

CL2 Color Recognition Sensor advantages

❖ Wide detectable color range:

Supports triple 16-bit RGB light source calculation, detecting nearly 3000 colors and accurately identifying small color differences;

❖ Fast response:

200 μs high-speed response; multiple sensing heads are available to match different target sizes and distances;

❖ Independent probe design:

Uses external detection head technology and fiber optics for the emitter, creating a high-intensity spot and reducing sensor head size for easier installation;

❖ Store 8, detect 4:

Simultaneously recognize four colors and store eight taught colors for simple operation.

As industrial intelligence advances, manual sorting is no longer sufficient for fully automated lines. Atonm color sensors offer a color-based sorting solution. Atonm will continue R&D and product iteration to support global smart manufacturing.