One difference between them is that the optical encoder can be applied for measuring the speed of a shaft rotation, whereas magnetic encoders can provide angular position information. In addition, you can use an optical encoder to measure linear displacement because it doesn’t need a stable light source and has a high resolution. On the other hand, if you want to measure displacement accurately with a magnetic encoder, you need to install an absolute reference frame next to your target. In addition, optical encoders are easy to use and can be used at a higher temperature than magnetic encoders.
How do optical encoders work?
An optical encoder reads the light intensity from a modulated light source and uses this information to detect changes in the rotation angle. For an optical encoder to work properly, it must have a light source and a detector. The light source is usually an LED with two different wavelengths of sunlight that blink at a high frequency. The sensor can be either an LDR (Light Dependent Resistor) or a PIN diode.
The optical encoder keeps track of the number of times the two lights change by using a frequency reference clock. In addition, it uses an internal counter set at zero when the system starts to count up as soon as it detects a change in frequency. The data is read from the optical encoder by using an RS-232 handshake.
How does an optical encoder provide a high resolution?
The easiest way to increase an optical encoder resolves to increase the number of lights in the modulator. You can also select a modulator that has a very small light spot at its output. For example, if you need high resolution up to 0.1 radians, you should use a four-light modulator with two light spots with diameters of 5 mrad and 10 mrad, respectively. To decrease the effect of noise on your measurements, you should install a filter and ensure that it has a low transfer function. On the other hand, if the light spot size is large, you’ll need to install a narrow band filter to fit the entire modulated light into the detector.
What are some of the applications of optical encoders?
You can use an optical encoder as a robot’s angle control device or motor speed controller. Another application of optical encoders is in laser tables and coordinate measuring machines (CMMs). The most common application of optical encoders is in disk drives. In addition, they are also used to measure motor speed and position in textile machinery, pick and place, and paper processing equipment.
How do magnetic encoders work?
Magnetic encoders are capable of providing angular position information. To use them, you will need to install a linear magnetic type gearbox, which is particularly useful for applications requiring small changes in the rotation angle. In addition, you can use any other gearbox with a linear shaft if it has a zero-backlash characteristic. As far as the automatic tracking method is concerned, it uses an accelerometer for measuring the shaft acceleration and converts it into error signals and differential signals that are then passed to the input pins of an A/D converter to provide angular position information. To increase the sensitivity of an encoder, you should increase the bandwidth by increasing its bandwidth ratio. On the other hand, a slow encoder is suitable for measuring rotation angles in slow machines.
What are some of the applications of magnetic encoders?
Magnetic encoders are used in robotics, industrial machinery, and medical equipment. They can also be found in spacecraft and satellites to control the movement of satellite gears. In addition to this, they are also used as torque sensors to detect the speed and direction of rotational motion. Magnetic sensors have been used in robotics devices such as mission planning and combining industrial machines for cutting or grinding raw materials or metals and aircraft instruments that measure valves’ position on jet engines and fuel valves’ work on airplanes.
How do you use the two types of encoders together?
The two types of encoders can be used together to provide a 20-bit resolution with a better solution than a single type of encoder. Because the magnetic encoders are more accurate, you should install them at a distance from your target to increase their resolution. In addition, optical encoders are easy to use and can be used at a higher temperature than magnetic encoders. The main difference between optical and magnetic encoders is that the optical encoder uses light intensity from modulated lights. In contrast, the magnetic encoder uses the changes in period caused by magnetized patterns on its disk surface.
To achieve a higher resolution, you should install a smaller-sized disk on the magnetic encoder. In the case of the optical encoder, you should use a detector with a larger coupling area for detecting changes in light intensity. In addition, optical encoders are easier to use than magnetic encoders because they don’t need a stable light source to record light intensity changes. Optical and magnetic types of encoders are used together because they have different characteristics, such as high performance and high-temperature resistance for the visual style and better resolution for the magnetic type.
To better use magnetic and optical encoders, you can use an encoder communication interface that supports single and dual channels. This interface will be used at the head end of a machine to provide angular position information and speed to the host system. An encoder communication interface is usually cheaper than a similar analog output interface because it uses fewer components and has fewer signal conversion processes.
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