Design and implementation of a linear IC based low cost digital tachometer for laboratory and industrial application

Any adjustable speed drives uses an incremental shaft encoder or a sensor and an electronic circuit for rpm as well as velocity estimation. The usual method of counting pulses generated by encoder or sensor in a fixed period of time produces a high precision velocity or rpm estimation in the high speed range. Tachometer plays a vital role in measurement of rpm of any rotating device and it is essential for any control system especially in servomechanism. Most of the controllers employed in the industry to control industrial process use a tachometer which gives the provision of feedback in a control circuit. The purpose of the project was to develop a digital tachometer using low cost linear digital ICs those are readily available in the markets of Bangladesh. This tachometer can be easily used for both industrial and laboratory purposes where it should be able to measure rpm and provide a voltage proportional to the speed of the shaft of the rotating device. At the same time efforts have been taken to reduce the cost of the tachometer as much as possible.