Automation InstrumentIt can be divided into six categories: on-site measuring instruments, on-site control instruments, on-site instrument actuators, display recording instruments, regulating control instruments, and special measuring instruments, each of which can be further subdivided into several subcategories. Jianheng Instrument editor will discuss in detail with everyone in this article.

Definition of Automation Instruments
Automation instruments are automation technology tools composed of several automation components with relatively complete functions. Automated instruments generally have multiple functions simultaneously, including measurement, display, recording, control, alarm, etc.

Origin of Automation Instruments
The true emergence of automation instruments was in the 1980s, when people effectively combined automation technology with industrial instruments through a control device, and then integrated control through assembled electronic devices. Later, with the continuous development of control technology, automation technology gradually became the main tool for the development of industrial instruments, and true automation instruments emerged.

The rapid development of new technologies such as microelectronics, computer technology, network communication technology, and information processing technology has had a profound impact on the innovation of automation instruments, and has become a new driving force for the development of industrial automation instruments. It not only enables industrial automation instruments to obtain information of objects more quickly, sensitively, reliably, and simply, but also breaks through the traditional framework of light, machine, and electricity, and develops towards intelligence, networking, bus, and openness. Today, we will use a diagram to help you clarify the "kinship" relationship of the automation instrument family.

Classification of Automation Instruments
Automation instruments can be divided into six categories: field measuring instruments, field control instruments, field instrument actuators, display recording instruments, regulating control instruments, and special measuring instruments. Each major category can be further subdivided into several subcategories.

1、 On site measuring instruments
On site measuring instruments are installed in industrial production sites, and can be divided into level instruments, pressure instruments, temperature instruments, flow instruments, gas analysis instruments, and liquid analysis instruments.
1. Level instrument
A level gauge is an instrument used in industrial production processes to measure liquid levels, the height of solid and powder accumulation, and the position of liquid-liquid and liquid-solid phase interfaces. There are two types of level instruments: continuous measurement and intermittent measurement: continuous level instruments and limit level instruments.
① Continuous level gauge
Continuous level gauges can be further subdivided into: direct reading level gauges (measuring liquid level based on the principle of fluid connectivity, such as glass level gauges, glass level gauges, quartz tube dual color level gauges), capacitive level gauges, buoyant level gauges (such as magnetostrictive level gauges, fiber optic level gauges, float level gauges, servo level gauges, float steel strip level gauges, float ball level gauges, magnetic flap level gauges), laser level gauges, ultrasonic level gauges, radar level gauges (such as pulse radar level gauges, guided wave radar level gauges), external mounted level gauges, RF level gauges, differential pressure level gauges, heavy hammer level gauges
② Limit type level measuring instrument
The common limit type level measuring instruments are divided into capacitor/pole level switches, float level switches, tuning fork level switches, rotary blade level switches, and ultrasonic level switches.

2. Pressure gauge
Pressure gauges are instruments used to measure changes in medium pressure or differential pressure during industrial production processes. Pressure instruments can be divided into liquid column pressure gauges (such as U-tube pressure gauges, single tube pressure gauges, inclined pressure gauges), pressure transmitters, differential pressure transmitters, pressure sensors, pressure gauges, pressure switches, and glass tube liquid.

3. Temperature gauge
A temperature gauge is an industrial automation instrument that measures the temperature of an object. Temperature instruments can be subdivided into glass tube liquid thermometers, pressure thermometers, thermocouples, thermistors, temperature transmitters, bimetallic thermometers, temperature switches, optical thermometers, radiation thermometers, and non-contact infrared thermometers.

4. Flow meter
Flow meters, also known as mass flow meters, can be subdivided into mass flow meters (such as Coriolis mass flow meters, thermal mass flow meters), volumetric flow meters (scraper flow meters, waist wheel flow meters, elliptical gear flow meters), punch plate flow meters, flow switches, speed flow meters (such as rotor flow meters, turbine flow meters, ultrasonic flow meters, electromagnetic flow meters, vortex flow meters), open channel flow meters, target flow meters, differential pressure flow meters (such as orifice flow meters, nozzle flow meters, Venturi tube flow meters, curved tube flow meters, V-cone flow meters, pitot tube flow meters, constant velocity tube flow meters)

5. Gas analysis instrument
Gas analysis instruments are process analysis instruments used to measure gas composition, which can be subdivided into gas chromatography/mass spectrometry analyzers, oxygen analyzers, toxic/flammable gas detection instruments, thermal conductivity analyzers, magnetic conductivity analyzers, electrochemical analyzers, infrared analyzers, ultraviolet analyzers, laser gas analyzers, and photoelectric gas analyzers.

6. Liquid analysis instrument
Liquid analysis instruments can be subdivided into electrochemical analyzers, UV visible light analyzers, infrared absorption spectroscopy analyzers, distillation range analyzers, liquid chromatography/mass spectrometry analyzers, water quality analyzers (such as pH meters, conductivity meters, concentration/turbidity meters, dissolved oxygen analyzers, residual chlorine analyzers, DOC/COD analyzers), and viscosity/density meters.

2、 On site control instruments
On site instruments refer to instruments installed on production sites for measuring various process parameters, executing various control instructions or converting signals, and achieving communication. On site control instruments include pneumatic control instruments, hydraulic control instruments, and electric control instruments.

3、 On site instrument actuator
On site instrument actuators are divided into pneumatic diaphragm control valves, pneumatic diaphragm control valves used in conjunction with valve positioners, electrical valve positioners, and intelligent electrical valve positioners.

4、 Display recording instrument
Display recording instruments are divided into paper-based recorders, paperless recorders, display instruments (analog display instruments, digital display instruments, touch screen HMI and CRT display terminals, flash alarm instruments).

5、 Adjust control instruments
Including PID regulators PLC、 Digital control systems (such as alarm continuous control systems, DCS systems, FCS bus control systems, ESD emergency shutdown systems, SIS safety instrumented systems), IPC industrial computers.

6、 Special measuring instruments
Special measuring instruments include shaft vibration measuring instruments, shaft displacement measuring instruments, tachometers, weighing instruments, thickness measuring instruments, signal calibrators, flame detectors, etc.

The classification of automation instruments is not static. With the development of instrument technology, the classification boundaries of some products have merged. For example, bus pressure transmitters (with PID control function) belong to both on-site measuring instruments and regulating control instruments.