Due to the increasing number of applications and the increasing complexity of modern industrial production, the demand for more sophisticated and reliable sensors is increasing. For example, the identification of color detection and color change is more complicated. One of the applications, such as the packaging machine in which the machine is to determine which product is placed in what color, when the candy wrapper should be cut, how to ensure that the toy, perfume bottle or other product is facing the cellophane window of the box. and many more.
A more difficult test task like this generally uses a color sensor as the core solution. This article will provide some considerations to help you choose the sensor that best suits your application.
Currently, there are two basic types of sensors for color recognition (both of which are photoelectric): one is a color-coded sensor that uses an incandescent light source or a single-color LED light source; the other is RGB (red, green, and blue) colors. A sensor that detects the ratio of the reflection of the target object to the three primary colors to identify the color of the object.
Many of these devices are thermo-reflective, beam- and fiber-optic and are packaged in a variety of metal and polycarbonate enclosures. Typical outputs include: NPN and PNP, relays, and analog outputs.
Color-coded sensors are often used to detect spots on specific color patches or objects. Instead of directly measuring color, color-coded detection is achieved by comparison to non-color-coded areas. The color-coded sensor is actually a reverse device, the light source is mounted perpendicular to the target object, and the receiver is mounted at an acute angle to the object, so that it only detects the scattered light from the target object, thereby preventing the sensor from directly receiving the reflected light, and The beam focus is very narrow. Both incandescent and monochromatic sources can be used for color code detection.
RGB color sensors are highly reliable for detecting similar colors and tones. It performs color detection by measuring the reflection ratio of the three primary colors constituting the color of the object. Because of the high precision of this color detection method, RGB sensors can accurately distinguish very similar colors, even different tones of the same color.
As we have seen, color sensors come in several sizes and different performances. To choose the right sensor, you must analyze your application by understanding the following issues:
- What is the purpose of the application?
- What is the current power type? AC or DC? What is the rated voltage?
- What equipment should the control system control? Is the conveyor still an inspection system?
- What is the output load?
- What is the speed of the system required? Describe the number of parts or conveyor speeds passed per minute.
- What is the distance between the sensor mountable point and the target?
- What is the environment? Including cleaning, dust, moisture, heat, cold and other aspects.
- How much space can I install the sensor on site?
- Is there a fee limit?
- What is the size and shape of the target object?
- What is the target surface? For example, shiny or scattering.
- At the inspection site, what is the background color behind the target object?
- How far is the background from the target object?