Sensor Lets Machines See Color Intensity

EMX Industries Inc., introduced the ColorMax-1000, the first color sensor that outputs color intensity. The ColorMax-1000 color sensor has a high-intensity white LED that projects modulated light on a target. The sensor analyzes the reflected light for its constituent RGB values and intensities. High accuracy, stability, and sophisticated software algorithms enable the ColorMax-1000 to meet the resolution and speed requirements of advanced manufacturing processes.

Traditional color sensors output only a "match/no match" condition to the machine controller. In contrast, the ColorMax-1000 sensor also outputs the analog values for each RGB reading. Now the PLC or operator can see how much color, not just which color. Operators can analyze the RBG data to spot trends and diagnose the causes of color variation. In addition, instead of the sensor making the match decision, now the match decision can be made in a PLC or other controller. For the first time, users have the option of developing their own algorithms for color control.

Unlike other color sensors that can be programmed to match only one to eight colors, the ColorMax-1000 has 15 hexadecimal unique color channels that are stored in non-volatile memory and compared against the reading of the target color. This reduces the number of sensors required for some applications, because now one sensor can be used where several were needed before. In addition, it gives users more flexibility in changing manufacturing setups without the need to reprogram the sensor. This is increasingly important as North American factories move to high-mix low-volume manufacturing which often requires frequent color changes.

The ColorMax-1000 is the only color sensor available in an M30 threaded enclosure, familiar to any engineer who has worked with proximity sensors. Normally, color sensors are square shaped to accommodate a beam-splitting mirror or light source and receiver combination. To achieve a cylindrical design, EMX engineers had to develop an innovative optics arrangement and a special lens.

The 110mm-long sensor fits a standard 30mm diameter hole. Installation is fast and easy: the technician screws in the sensor and tightens the jamb nuts. The distance can be adjusted up to three inches simply by turning the sensor. In contrast, all other color sensors require users to install a special mounting bracket. Should the operating distance of other sensors need adjustment, the bracket has to be moved and new holes may need to be drilled.

The detection range for the ColorMax-1000 sensor is 30mm to100mm. At recommended operating distance (50mm) the beam diameter is a tiny 4 or 8mm spot - enabling engineers to pinpoint readings and minimize background color interference. Electrical noise affects sensing resolution and sensitivity. If a color variation is smaller than the noise, the sensor will not be able to detect the variation, meaning that a subtle difference in color will go undetected. Likewise, when presented with the same color twice, a sensor with electrical noise may report a color variation erroneously.

By employing low-noise technology in the ColorMax-1000 sensor, EMX reduced color variation to 0.5% - the best specification in the industry. High resolution is especially important for detecting color variations at high speeds. In applications where the target is in front of the sensor for a very short period of time, a sensor with a slow sampling speed can limit the speed of manufacturing. The 5 kHz sample speed of ColorMax-1000 is two to five times faster than the speed of other color sensors - fast enough to keep up with demanding high-speed manufacturing processes.

Because color sensing is based on a measurement of reflected light, color sensors can be 'fooled' by the luster of shiny surfaces. This is particularly true of metallic paint used in automobile parts. EMX's new color sensor overcomes this challenge by using sophisticated software algorithms that ignore luster. Few color sensors offer this capability.

The ColorMax-1000 is the only color sensor that can be programmed via a PC, simplifying sensor installation. If additional sensors are added or if a sensor is replaced, the technician can copy and paste the color profiles stored in the PC software. Color profiles will not be lost if a sensor stops working. In addition, EMX's new sensor is the only color sensor that automatically detects the PLC connection for PNP or NPN configuration during setup. This feature simplifies ordering and reduces stocking requirements by 75%, because users and distributors no longer need to stock different versions of the sensor.

Unlike some competing sensors, the ColorMax-1000 includes both auto-teach and manual calibration. This makes the sensor easy for low-skill operators to calibrate, yet it provides the ability to be finely tuned. LED indicators for power, programming, and detection functions aid in setup and troubleshooting. The ColorMax-1000 sensor features an IP67-rated nickel-plated brass housing suitable for a wide range of manufacturing environments, plus short-circuit, over-current, and reverse polarity protection. Connections are made via a circular 12-pin connector.

For operational security, a supervisor may lock the unit's settings, either remotely or directly on the unit. This feature prevents operators from changing the sensor settings in order to avoid reporting manufacturing quality issues. Most color sensors do not offer this level of assurance.