Electronic tachometer: principle of operation and scope
To optimize engine performancePrecise measurements are needed, which can be done with modern instruments - electronic tachometers. Such a mechanism with high accuracy will show the angular velocity of the motor shaft, which is expressed in rpm. With the help of special devices it is possible to determine the linear speed of the rotating mechanism, it is expressed in m / sec. The electronic tachometer is successfully used in production during commissioning. It helps correctly calibrate the engine and optimally adjust the control system. The I & C services actively use this device in their daily work.
In addition, the electronic tachometer with successused in the automotive industry. It helps motorists monitor engine speed and choose the most optimal mode of operation. For example, with a season change or during a cold / hot period, this device becomes an indispensable assistant, because it prolongs the life of the car.
This device has long been used in the mostresponsible industries, where it is necessary to exercise constant control over the rotational speed of the motor shaft, internal combustion engine, turbine, etc. In aircraft construction, the electronic tachometer is one of the main instruments controlling the operation of the turbo engine. From his testimony directly depends the life of the entire crew and passengers. Failure of the tachometer can lead to disaster.
Let's look at the operation of this device onexample of a small scheme, which is easy to find on the network. Any electronic tachometer should receive information from a sensor that measures the engine speed or its linear speed. This is achieved by directly contacting the movable part of the instrument with the motor shaft or remotely using an induction or laser sensor.
In our case, 70-90 turns of the PEV-1 wire,wound on the main ignition wire of the car, play the role of an induction sensor, which uses our homemade electronic tachometer for its work. The circuit of connecting the wire is simple - one end of the coil goes to the ground, and the second - to the control circuit. The rest of the circuit consists of a trigger that allocates a useful signal and passes it to a counting device based on counters. The quantity calculated for a unit of timepulses is given to the matching scheme, whichmakes this information understandable to a digital indicator. The duty cycle of the device is set by means of a multivibrator or a pulse generator based on a quartz element.
Such an electronic tachometer can have the mostdifferent variants of execution. Other solutions are used for its implementation. The computing part can be constructed on the basis of a microprocessor. This is a good practice in writing programs for its work. In this case, it is best to use microprocessors with the possibility of reprogramming. When designing, do not forget about the device's noise immunity.