What is a display adjustment instrument

display instrumentIt refers to an instrument that receives the output signal of a detection instrument and displays the measured value. It is used in conjunction with detection instruments, transmitters, and sensors. Display instruments generally indicate the detection values sent by sensors such as temperature, pressure, flow rate, level, and mechanical quantity with pointers or numbers. According to different display modes, it can be divided into analog display instruments, digital display instruments, and character image display instruments.

　　Regulating instrumentAlso known as a regulator, its function is to compare the measured parameters in the production process with the set parameters, and then send adjustment signals to the actuator according to a certain adjustment rule.

Regulating instruments are divided into intermittent regulators and continuous regulators according to different adjustment methods; According to the structural form, it can be divided into base type, unit combination type, and assembly type; According to the working energy and medium, it can be divided into self operated, electric, pneumatic, and hydraulic types. Some regulating instruments also have detection and display parts.

The indicating component of analog indicating instruments is generally called an indicator, the display component of digital display instruments is called a display, and the display device used in computer human-machine dialogue systems is generally also called a display.

Analog indicating instrumentGenerally, pointers are used to indicate measurement values, which come in two forms: full range indication and deviation indication. The input signal is a unified signal (4-20mA DC) sent from various transmitters, and there are also direct connections between indicator instruments and sensors. Some indicator instruments also have control output functions. Figure 1 shows the commonly used dynamic coil indicator regulator. The ruler has a length of 100 millimeters and an indication accuracy of level 1. It has two pointers, red and black. When the deviation value is equal to zero, the two pointers overlap. The indicator adopts a wire supported structure with high sensitivity and long service life. This type of instrument is easy to operate, easy to maintain, cost-effective, and can be adapted to various transmitters, making it widely used in process detection and control instruments. It is usually installed on the dashboard for operators to monitor and control on-site operations. Since the 1970s, new types of light-emitting devices have been constantly emerging, gradually replacing traditional pointer type indicator instruments. Such as high brightness and high-resolution plasma indicator adjusters, color LCD display indicators, and LED deviation indicators.

　　digital display instrumentUse digital display to indicate the instrument being measured. The display devices used include fluorescent digital tubes, liquid crystal displays, and light-emitting diodes (also known as LED digital tubes). It was developed on the basis of analog indicating instruments. Especially in the late 1960s, the emergence of digital integrated circuits led to rapid development of digital display instruments. Compared with analog indicators, digital displays have the advantages of high resolution, large range, convenient reading, no parallax, and easy connection with computers. Its disadvantage is that it is difficult to interpret the trend of the measured changes; The frequent jumping of numbers affects the interpretation. Therefore, analog indicator instruments are still the mainstream of display instruments. Digital display instruments are usually used when readings are required. Figure 2 shows a digital temperature indicator regulator. It can display set values, measured values, and deviation values, and has upper and lower limit settings, alarm output, and control functions. Digital display instruments are classified into various types based on their principles, display functions, and points (Figure 3). It is matched with various transmitters to display and control the measured data. Generally, it is equipped with a printing output device and can be connected to a computer. Various intelligent digital display instruments with microprocessors that emerged in the late 1970s have functions such as high display accuracy, self calibration, and self diagnosis, and can communicate with computers.