Digital transducer
- 2. INTRODUCTION WORKING PRINCIPAL CONSTRUCTION OF DIGITAL TRANSDUCER CLASSIFICATION OF DIGITAL TRANSDUCER ADVANTAGES & DISADVANTAGES OF DIGITAL TRANSDUCER APPLICATION
- 3. • Any transducer that presents information as discrete samples and that does not introduce a quantization error when the reading is represented in the digital form may be classified as digital transducer.. • What is encoder? • Any transducer that generates a coded of a measurement can be termed an encoder. • Most transducer used in digital system are primarily analogue in nature and incorporate conversion to provide the digital output. Many special technique have been developed to avoid the necessity to use a conventional analogue –to-digital conversion technique to produce the digital signal.
- 4. Some of the techniques used in transducers which are particularly adaptable for use in digital system are introduced in following ways- Shaft encoder Digital resolvers Digital Tachometers Hall effect sensors Limit switches The use of encoder disc for absolute and incremental position measurement and to provide measurement of speed are outlined. The application of linear grating for measurement of translational displacement is compared with the use of Moire fringe techniques. Synchro devices and the various techniques used to produce a digital output.
- 5. CLASSIFICATION OF DIGITAL DISPLACEMENT TRANSDUCER They are basically are of two types-absolute and incremental encoders. ABSOLUTE ENCODER- An absolute encoder maintain position information when power is removed from the systems. The position of the encoder is immediately on applying power. The system does not need to return to a calibration point to maintain position accuracy. A high resolution wheels measures the fractional rotation,and lower resolution geared code wheels records the number of whole revolution of the shaft.
- 7. The problem caused by reverse motion in the case of tachometer encoder are solved by using incremental encoder. The incremental encoder use ( At least two sometimes three) signal generating elements. The two tracks in this case are mechanically shifted by ¼ cycle relative to each other. This allow detection of motion which signal rises first .thus, an up down pulse counter can be used to subtract pulses whenever the motion reverse. A third output which produces one pulse per revolution at a distinct point,is sometimes provided for zero reference.
- 9. door control services Robotics Drilling machines Length measurement CNC machines Automatic welding Radar Winding machines Wind turbines Telescope Medical equipment Bar code readers
- 10. Motor speed/rpm readout Linear measurement /cut to length
- 11. Applicaion of digital resolvers BLOCK DIAGRAM Application Position and velocity sensing Medical devices CNC machines tools Brushless DC servo commutation. Position and velocity sensing
- 12. It is an instrument measuring the rotation speed of a shaft or a disk, as in motor and other machine. The word comes from Greek tachos means “speed” and metron, means “to measure”. Digital tachometers are particulary suitable for precision measurement and monitoring of all the time related quantities, which are able to be converted into a proportional frequency using appropriate sensors time related quantities. The instrument can be programmed to measure absolute value ratio , or proportional difference.
- 13. application Digital tachometer kit Traffic engineering In trains and light rails vehicles In analogue audio recording