Composition and classification of precision instruments

　Fine instruments refer to equipment and devices used to generate and measure fine quantities, including observation, monitoring, measurement, verification, recording, transmission, transformation, display, analysis, processing, and control of fine quantities. Fine instruments are an important branch of instrument appearance.


There are various types and structures of precision instruments. For precision instruments used for measurement, their structure can be divided into eight major functional components: reference, sensing conversion, conversion and expansion transmission, aiming/reading, data processing, display and recording, drive control, and mechanical structure. However, it is not necessary to include the eight major functional components mentioned above in a precision instrument, but rather to choose according to the requirements of the instrument's functions.


1. Reference component


The reference component provides a standardized measurement for measurement, and the measurement results must be compared to obtain accurate measurement values. Therefore, it is the primary step in determining the accuracy of precision instruments.


There are many types of reference devices, such as standard devices used for measuring geometric quantities (length and angle): measuring blocks, fine measuring screws, line rulers, measuring discs, polyhedral prisms, multi tooth indexing discs, grating rulers (discs), magnetic grating rulers (discs), induction synchronizers, light waves, etc. For complex parameters, there are standard components such as involute templates and surface roughness templates, as well as standard circular motion, involute motion, and gear motion equipment that provide standard motion. In addition, there are standards for hardness blocks, frequency meters, as well as time, illumination, flow rate, chromaticity, laser parameters, temperature, force measurement, and weighing. You can choose according to your needs.


2. Sensory conversion component


The sensing conversion component measures the sensing and picks up the original signal for further conversion, processing, and analysis. Its accuracy directly affects the accuracy of the entire instrument.


Some instruments only use the sensing conversion component to sense the original signal, while others also perform a signal conversion at the same time. There are two main types of sensing conversion components: one is contact type, such as various mechanical probes; One type is non-contact, such as pneumatic non-contact measuring heads, optical probes, infrared, eddy current measuring heads, pickups, etc.


3. Transform and expand transmission components


The conversion and expansion transmission component further converts and expands the small signals converted from touch through various principles (light, machinery, electricity, gas), becoming signals that can be directly received by the observer or its next component, such as display or further processing.


4. Aiming/reading components


The aiming/reading component senses the measured/standardized quantity, used to zero/read.


The aiming component is used for sensing and measuring, and requires accurate zero indication. Generally, it is not used for reading, so its sensitivity is not required. The reading component is used to sense the standard quantity and generate measurement results. In actual measurement, the two are interchangeable rather than definite. But some instruments cannot be interchanged.


5. Data processing components


The data processing component processes, proofreads, and calculates measurement data. Usually completed by microprocessors or microcomputers.


6. Display recording component


The display and recording components are used to display and store measurement results, including many types, such as pointer dials, recorders, digital displays, printers, fluorescent image displays, as well as various ROM and RAM memories, disks, CF and SD memory cards.


7. Drive control components


The driving control component drives the measuring head of the measuring part to move or drives the workbench to complete the measurement action; In automatic detection instruments, it expands and converts the output of data processing components to the measured error amount, driving the execution components to complete the system's actions.


8. Mechanical structural components


Mechanical structural components are mechanical structures that connect, support, protect, limit, and guide movement to ensure the completion of other component functions. The main components include the base, bracket, guide rail, workbench, shaft system, and other components, such as fine adjustment, locking, limit, protection, and other mechanisms. It is an indispensable component in the instrument, and its accuracy sometimes plays a decisive role in affecting the accuracy of the instrument.

According to different measurement objectives, precision instruments can be divided into the following categories:

Geometric precision instrument


It mainly includes fine instruments for detecting various geometric quantities, such as vertical Goniometer, laser interferometer and comparator, Theodolite, three coordinate measuring machine, roundness meter, profiler, Scanning tunneling microscope and other measuring instruments.

Thermal precision instrument


Mainly including temperature, humidity, pressure, and flow detection precision instruments, such as various barometers, vacuum gauges, multi wavelength temperature measurement surfaces, flow meters, and altimeters.

Mechanical precision instrument


Mainly including various force measuring instruments, strain gauges, acceleration and velocity measuring instruments, torque measuring instruments, vibration measuring instruments, universal material testing machines, and Brinell hardness testers.

Time frequency precision instrument


It mainly includes various timing instruments and appearance, Atomic clock, time and frequency measuring instrument, etc.

Electromagnetic precision instrument


It is mainly used to measure various electric quantities and magnetic quantities, such as Ammeter, Voltmeter, power meter, resistance meter, capacitance meter, electrostatic meter and magnetic parameter meter.

Radio precision instruments


It mainly includes oscilloscope, signal generator, phase measuring instrument, Spectrum analyzer, dynamic signal analyzer, etc.


Optical and acoustic precision instruments mainly include spectrometers, photometers, colorimeters, laser parameter measuring instruments, optical transfer function measuring instruments, noise measuring instruments, and sonar measuring instruments.

Ionizing radiation precision instrument


Mainly including various types of radioactivity, nuclide measurement, X and λ Isoradiometric instruments, etc.