New Sensor Has PreciseColor Discrimination

Engineers have long sought a sensor that can identify the subtlest color differences at the speeds and repeatability required by production lines. Well, their search may be over thanks to Omron Electronics Inc. (Schaumburg, Ill.). The company recently released its new E3MC RGB (red/green/blue) color sensor, which Omron says features a unique threshold sensitivity adjustment that allows precision color differentiation—even among hard-to-distinguish shades of blue.

Users can change the E3MC’s threshold levels to one of several “fine” or “coarse” settings to differentiate among up to four highly similar colors. The sensor’s sensitivity adjustment can even distinguish between different “shades” of white.

E3MC can store up to four colors in memory—which is more than any other product in the industry. It’s available in single output and four-output versions.

Free angle optics

Incorporating Omron’s advanced light wave sensing and free angle optics, as well as temperature compensation circuitry, the E3MC is uninfluenced by changes in ambient temperature, brightness or positioning of objects being sensed.

Here’s how the sensor detects colors. The reflection ratio of a primary color (red, green, or blue) reflected by an object varies with the chromaticity of the object. By using an advanced, multilayer polarized filter known as FAO (free angle optics), the E3MC emits red, green and blue light on a single optical axis so the light will be reflected by the object. E3MC receives light reflected by the object through its receiver and processes the light’s red/green/blue ratio to determine its color.

Teaching colors

The user teaches or “registers” the color of the object to be sensed using manual threshold level adjustments to fine tune the system. Users simply install the sensor and focus on the object to be detected, move the selector switch to teach, and press the teach button, which stores the color in EEPROM (electrically erasable and programmable read only memory). Color level is displayed on a column of green LEDs.

If the process requires differentiating various shades of the same primary color, the registered color can be tuned by moving the switch to adjust mode and using the select buttons to adjust the threshold. The threshold is displayed on a scale of red LEDs. Users can then move the switch to run mode, and start production. When the detected color matches the registered color, the output changes state—either sinking or sourcing outputs are available.

Available both with and without fiber optics, the E3MC RGB also has a reliable, maintenance-free LED light source and quick-disconnect connectors to simplify installation.

For more information, visit www.controleng.com/info .

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