Digital Tachometers: Basics, Features and Working Principle

Digital tachometers are used to measure the rotational speed of objects and can be categorized into contact and non-contact according to the measurement method. The contact type digital tachometer is limited and not convenient enough to use, the safety is also lower, but the price is relatively low, in industrial control, we often use non-contact type digital tachometer. Digital tachometer is one of the important measuring instruments in daily life, and has a wide range of applications in steam, electronics, textile, paper and other aspects.

Working Principle of Digital Tachometer

Take the principle of the more commonly used non-contact digital tachometer in ATO Store as an example:

When measuring, a piece of aluminum foil is pasted on the rotating shaft to be measured as a reflective body, when the reflective body turns to the front of the tachometer's photoelectric sensor, the infrared beam emitted from the photoelectric sensor is reflected back, and at the same time, it is received by the infrared receiver tube on the photoelectric sensor, which produces an impulse signal, so as to calculate its rotational speed and display it digitally on the screen.

Features of Digital Tachometer

1. With microcomputer (CPU) technology, optoelectronic technology, semiconductor laser technology and other advanced technologies, to achieve contact or non-contact measurement of rotational speed, line speed, line length.
2. Wide measuring range with high resolution.
3. Large screen liquid crystal display, clear reading without parallax.
4. Green backlight, to ensure that in any light environment can be used normally.
5. The digital tachometer can store the maximum value, minimum value and the last displayed value of the measurement, and at the same time store up to 96 consecutive measurement values, which is convenient for users to collect and record the measurement data. (When the measurement value is refreshed three times, the meter will start to store the measurement data.)
6. Touch accessories and photoelectric accessories can be converted at any time to realize multi-purpose.
7. New type line speed sensor with notch can easily measure the line speed or line length of wire, cable, rope and other linear objects.
8. Digital tachometer's structure is sturdy and delicate, the whole machine adopts durable and preferred electronic components, the shell is made of light weight and hard ABS plastic, beautiful and easy to operate.

Operate Instruction of Digital Tachometer

Photoelectric speed type:

• Stick a reflective mark to the object to be measured, set the function selector switch to non-contact speed gear (rpmphoto), remove the contact measurement accessories.
• After installing the battery, press the measurement button to illuminate the visible beam onto the tested target (where the reflective strip is attached). Once the visible beam is aligned with the tested target, the measurement can begin.
• Release the measuring button after the display value is stabilized. At this time, there is no display, but the measurement result has been automatically stored in the meter, and the measurement is finished.

Contact speed type:

• Set the function switch to rpmcontact and install the contact speed measuring accessories.
• Close the contact rubber head to the tested object and rotate it synchronously and coaxially with the tested object.
• Press the measurement button to start the measurement, release the measurement button when the display value stabilizes, the measurement value will be stored automatically and the measurement will be finished.

Contact wire speed type:

• Turn the switch to the contact wire speed range (m/mincontact) and replace it with the contact wire speed measurement accessory.
• Place the linear speed accessory tightly against the object being tested and rotate it synchronously with the object being tested.
• Press the measurement button to start measurement, release the measurement button after the display value is stabilized and the measurement value is automatically stored in the instrument, then the measurement is finished.

Note: Because the perimeter of the outer surface of the wire speed sensor is different from that of the inner groove, when the outer surface of the wire speed sensor is in contact with the object to be measured, the displayed result is the normal value: when the inner groove of the wire speed sensor is in contact with the object to be measured, the displayed result should be multiplied by 0.9 to be the real result of the measurement. (e.g. measuring wires, cables, ropes and other linear objects).

Notes on the Use of the Digital Tachometer

1. Please operate the digital tachometer correctly when using it and use it under the conditions limited by the technical parameter table.
2. Avoid using or storing the digital tachometer in flammable or explosive environments.
3. Avoid contact with corrosive chemicals.
4. When measuring objects that are adjusted to rotate, it is recommended to use photoelectric measurement. Avoid injuries due to excessive rotation speed during contact measurement.
5. When the digital tachometer is not used for a long time, remove the battery and place it properly.