True color recognition sensors "read" colors by emitting white light, analyzing three beams of reflected colored light (red, blue, green), then measuring the level of light reflected back on each wave length.

The level of reflected light is compared to the value stored in the sensor's memory. If the value is within its tolerance limits, recognition of that value triggers the output. Typical uses of true color recognition sensors include sorting by product color, or exactly matching a memorized color to that of a passing target.

Balluff offers three types of full color detection photoelectric sensors:
BFS 30M, BFS 27K and 26K.

BFS 30M tubular housing color sensors are designed to verify the presence of targets that can be differentiated by color. These sensors project a modulated high intensity white light onto a target and analyze the reflected light for its constituent RGB (red, green, blue) values. If the readings of all of the three colors fall within the preprogrammed parameters, the sensor issues a discrete signal that indicates a color match. Two models have been designed to solve a variety of the most demanding applications, a 7-discrete output unit and a binary (4-bit) hexadecimal output unit.

BFS 27K advanced full color photoelectric block housing sensor uses a pulsed white LED light source and the latest full color receivers for the broadest detection of colors, and is insensitive to ambient light conditions. The reflected light is registered by three different receivers (red, green, blue), and then evaluated for the correct level of Chromaticity, or Chromaticity + Intensity, using three channels. The BFS 27K can detect up to three different colors at a time. It has ten tolerance levels, making it ideal for situations where colors are critical. The 50x50x25 mm dimensions make installation simple, even in tight locations.

The BFS 27K simplifies set-up and use with a 4-digit display and a simple two-button set-up procedure. Complete remote control is available on the RS485 serial interface versions. Other advanced features include programmable, pulse stretcher time delay up to 40ms for fast targets, key lock to prevent tampering, and a synchronization input or blanking feature that allows extensive application flexibility and a RGB (Red, Blue, and Green) value via RS485 offering millions of color combinations and color processing possibilities.

BFS 26K is a compact color block housing sensor that works as a true 3-channel color recognition system without needing an external light source. The sensors never let themselves be confused by the ambient lighting like the human eye. No color remains undetected by the sensor.

The BFS 26K uses an integrated, pulsed white light source, eliminating the need for external illumination and making it insensitive to ambient light. Its unique receiver measures the red/green/blue component of the reflected light in a single processing step. And thanks to the white light emitter, the BFS 26K can even distinguish shades of gray.

With its dimensions of just 50 × 50 × 17 mm and a 270° rotate-able connector, the BFS 26K sensor fits in the smallest spaces and can be programmed either through the control line or using 2 teach-in buttons. Each of the three digital outputs can be calibrated using five tolerance levels. Numerous special functions such as color scanning, pulse expansion and blanking input provide additional application flexibility.

Applications

• selecting assembly parts, bottles, package contents, etc.;
• positioning objects based on applied color markings like a product label, color features or packaging;
• inspecting quality in the production process;
• checking mechanical or chemical processes such as polishing, plating, or gluing;
• identifying products based on color, the application possibilities for the new BFS-26K span the rainbow.