Digital Display Meter

A digital display meter is a kind of instrument that displays the measured value in decimal digital form. And it can be classified according to the following two methods: (1) According to the structure of the instrument, it can be divided into two types, one with microprocessors and the other without microprocessors; (2) According to the input signal forms, it can be divided into the following two types ---- voltage type and frequency type. The input signal of voltage-type digital display instrument is the continuous signal of voltage and current output by analog sensor. The input signal of the frequency-type digital display instrument is the discrete signal of the frequency, pulse and code output by the digital sensor.

This paper is going to introduce the digital display meter from its classification, working principle, characteristics and uses.

Classification:

Commonly, the digital display meters can be divided into mechanical type and electronic type.  

① Mechanical digital display meters:

Using gear and other mechanical transmission devices to connect the detection instrument and the wheel type digital display together. And the change of the measured variable is reflected by the mechanical linkage, so as to realize the digital display of the displacement, speed and flow rate. One of this kind of meters is mechanical odometer.

② Electronic digital display meters:

An electronic meter, consisting of components such as transistors and integrated circuits, is divided into voltage type and frequency type according to the input signal forms.

Working Principle:

①Voltage-type meter:

It accepts voltage or current signal and then, through analog-digital conversion, converts the input signal into the corresponding intermittent signal which is generally a two-decimal coded signal, and finally the figures will be shown by digital decoding and photoelectric display devices.

② Frequency-type meter:

With Receiving pulse or frequency signal and by counting and logical control of the input signal, it accumulates the number of pulses within a certain time interval, and then converts the calculated pulse number into the corresponding two-decimal coded signal, and finally achieves digital display by decoding the signal. It can also directly accept the digital signal from the detection instrument to achieve the digital display after transformation and data processing.

Characteristics:

The reading is accurate and convenient, the measurement speed is fast, and the digital signal output can be provided. If equipped with additional functions, the meters can achieve measurement alarm and fixed value control.

Uses:

In the process of production, the meter is combined with various detection instruments, which can be used to display process variables such as temperature, pressure and flow rate, and thus used for visual observation, digital recording or data remote processing, and used in laboratory precision test and others as well.