What is a digital meter and what are the types of digital measuring instruments

A digital meter is a meter in which the measurement results are displayed in digital form. It is divided into two categories: organic and electronic. The former is such as kilowatt-hour meters (fire meters), etc., and the latter is such as digital multimeters, frequency meters, etc.

It has high accuracy, fast measurement speed, convenient reading and no reading error and estimation error. Some also have functions such as automatic range switching, encoded output, and connection with other instruments or computers.

A digital multimeter generally contains functions such as an ampere meter, voltmeter, ohmmeter, etc., and is sometimes called a multimeter, a multimeter, a multimeter, or a triplemeter. DMMs are suitable for portable devices for basic fault diagnosis, as well as devices placed on a workbench with a resolution that can be achieved.

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The so-called digital instrument is to convert all the measured (such as voltage, current, power, electric energy and other analog quantities) into digital quantities after sampling and holding, A D conversion into digital quantities as processed signals, and then use microcomputers and other means to analyze, process, transmit and 、.. the measured measurementsThere are many advantages over analog instruments. It is the development goal of instruments and equipment in the industrial field at present.

The digital meter is said as opposed to the analog meter. In terms of analog quantities, such as voltage and current, they are indicated by a pointer.

On the other hand, digital meters display voltage and current values through numbers. Of course, digital meters are much more complex than analog analog meters.

About the meaning of digitizer.

The full name of digitizer is the graphic digitizer, which is an external device that digitizes the position of points on the plane and contains the coordinate data in the Zen Mountain display or sends it to the computer. It is widely used in industries such as digital drawing, CAD, and GIS.

Classified according to the principle of composition:

Mechanical digital display instrument: the use of gears and other mechanical transmission devices to connect the detection instrument and the word wheel digital display, by the mechanical linkage to reflect the changes of the measured variables, to achieve displacement, speed and flow and other variables of the digital display; Electronic digital display instrument: An electronic instrument composed of components such as transistors and integrated circuits.

Classification by measurement type:

resistance measuring instrument; Signal frequency measuring instrument; voltage measuring instrument; pressure measuring instrument; temperature measuring instrument; Level gauges.

Digitizer is a kind of computer input device, which can accurately input various graphics into the computer according to the coordinate values, and can be displayed through the screen.

Digitizers, which are widely used for the input of design drawings in engineering, are used for computer-aided design (CAD). In recent years, it has also been used for non-keyboard (handwriting) input of Chinese characters, plus for personal digital assistants (PDAs). With it, there is no need to learn any kanji input.

method, you can enter Chinese characters naturally and conveniently. When using it to input Chinese characters, it will not affect people's thinking, and it also has a function that the keyboard cannot match: leave a handwritten signature to regret the name. It is useful for chiefs and elders when entering Chinese characters.

The working principle of the digitizer is roughly as follows: when the positioning device moves on the surface of the digital board, through electromagnetic and electrostatic induction, the graphic coordinate information on the digital board is digitized little by little (this is the origin of the name "digitizer"), and is transmitted to the computer, and then processed by the computer, it can be restored to an original graphic on the screen. This completes the digitization and import process of the graphic front paulownia.

Of course, as a non-mainstream way of typing Chinese characters, its input speed is not fast enough, and the accuracy rate is lower than that of keyboard input.

1) Digital display, there is no visual error in the reading.

2) The accuracy is generally higher, the digital electrical instrument because there is no moving part of the electromechanical instrument, so the mechanical friction, the impact of deformation is very small, as long as the quality and performance of the components are no problem, the digital instrument is relatively easy to make a very high accuracy instrument, such as the KM display meter accuracy produced by Shenzhen Keliheng Electronics has been reached, the CSS series products have reached the accuracy of one hundredth of a thousandth, and the accuracy of the general electromechanical instrument is not easy, Digital meters can be easily achieved, and there are currently some digital meters to achieve the degree of accuracy.

High sensitivity. Because some digital meters are equipped with various amplification lines or devices, they can measure smaller signals, such as voltage signals of about 1 V, current signals of about 1 mA, and frequency signals.

4) High input impedance. Digital instruments generally have their own working power supply, in addition to the measurement of current, the general impedance can be made higher, so that the measurement has little impact on the measured physical quantity.

5) Easy to use. In particular, portable and desktop instruments for laboratory use can be made into multi-range (currently there is a km meter system with -1999 9999 display range) and multi-functional instruments (can measure current, voltage, frequency, power, line speed, and rotational speed).

6) The anti-interference performance is poor, due to the high sensitivity of the digital instrument, the anti-interference performance is poor, and the changes in the external magnetic field and electric field are easy to cause changes in the reading, in order to solve this phenomenon; Shenzhen Keliheng Company has invested heavily in technology, applying advanced surface mount technology and electromagnetic isolation technology, and the arc design panel ensures the long-term stability of the instrument.

7) The accuracy of the digital instrument, the expression method is different from the pointer instrument, the digital instrument is generally more than the percentage of the above limit or reading value as the benchmark value, plus a few numbers to indicate the accuracy of the meter, such as km series digital display instrument, system accuracy DC), AC) full scale 1 word. Generally, the accuracy of the multi-functional, multi-range digital multimeter is different when the functions and ranges are different. Therefore, attention should be paid to the selection and use of digital instruments, and it is best to find a special instrumentation company to select the model for you.

A digital display instrument is a type of instrument that displays the measured variable in decimal digital form, and it is used with various sensor transmitters to display a variety of different parameters. Digital display instrument work.

The process is to send the detection signal to the preamplifier, and the preamplifier amplifies the small electrical signal output by the transmitter, and then carries out modular-to-digital (AD) conversion to convert the continuous electrical signal into.

Intermittent digital output and display as a numeric value in engineering units. Most of the measured variables have a non-current functional relationship with the displayed values of the engineering units. In the digital display meter, must.

It must be equipped with a linearizer for nonlinear compensation, and a scale transformation of various coefficients should be carried out so that the process variables are displayed in decimal engineering units.