36 professional terms and 11 commonly used terms i

There are 36 professional terms and 11 common terms in the instrument and meter industry

instrument workers will carry out daily maintenance and fault handling of instruments and meters in the production process, so they are required to involve a wide range of knowledge. How much do you know about the terms in the instrument and meter industry? Here are 36 professional terms and 11 common terms for you. Come and see if you know them all

instrument classification

the most common classification of detection and process control instruments is based on the role of instruments in the measurement and control system, which is generally divided into four categories: detection instruments, display instruments, regulation (control) instruments and actuators

technical terms

36 technical terms and 11 commonly used terms in the instrument industry

a quantitative interval defined by the upper and lower limits

note: "scope" is usually modified. For example: measurement range, scale range. It can be applied to the measured or working conditions

2. Measuring range

the measured range measured according to the specified accuracy

measuring range lower limit

the minimum value measured according to the specified accuracy

measuring range higher limit

the maximum value measured according to the specified accuracy

3. Span

algebraic difference between the upper and lower range values. For example, when the range is -20 ℃ to 100 ℃, the range is 120 ℃

4. Performance characteristic

determine the relevant parameters and quantitative expression of the functions and capabilities of instruments and meters

reference performance characteristic

performance characteristic achieved under reference working conditions

5. Linear scale linear scale

the scale in which the spacing of each division is in constant proportion to the corresponding division value

note: linear scales with constant spacing between scale divisions are called regular scales

6. Nonlinear scale non linear scale

the scale in which the spacing of each scale division is in non-linear proportion to the corresponding division value

note: Some Nonlinear scales have special names, such as logarithmic scale and square law scale

7. The suppressed zero scale

scale range does not contain the scale of the scale value corresponding to the measured zero value. For example, the scale of medical thermometer

8. Expanded scale

within the scale range, The disproportional extension accounts for most of the origin on the scale strain curve (if the tensile load is deformed, the tensile secant elastic modulus: the scale of the tensile stress length.

9. Scale scale

an ordered set of scale marks and all relevant numbers that form part of the indicating device.

10. Scale range

the range limited by the starting and ending values of the scale.

11. Scale mark

the scale line corresponding to one or more determined measured values on the indicating device Or other marks

note: for digital indication, the number itself is equivalent to the scale mark

12. Zero scale mark

synonym: zero scale line

a scale mark or scale line marked with a "zero" number on the dial (board)

13. Scale division

the scale part between any two adjacent scale marks

14. Value of scale division

is also called lattice value

the difference between the measured values corresponding to two adjacent scale marks in the scale

15. Scale spacing

the distance between the centerlines of any two adjacent scale marks measured along the same line segment representing the scale length

16. Scale length

the length between the beginning and end scale marks of the line segment passing through the midpoint of all the shortest marks on a given scale

note: this line segment can be a real or imaginary curve or straight line

17. Minimum scale value

the measured value corresponding to the scale start mark

18. Maximum scale value

the measured value corresponding to the scale end mark

19. Scale numbering

the whole group of numbers marked on the scale, which corresponds to the measured value determined by the scale mark, or only represents the numerical sequence of the scale, which the company claims is a milestone event mark

20. Zero of a measuring instrument

when any auxiliary energy required by the measuring instrument operator is connected and the measured value is zero, the direct indication of the instrument

① when measuring instruments use auxiliary power supply, this term is usually referred to as "electrical Zero"

② when any auxiliary energy of the instrument is cut off and does not work, the term "mechanical zero" is often used

21. Instrument constant

in order to obtain the indicated value of the measuring instrument, it is necessary to multiply the direct indicated value by a coefficient

note: when the direct indicated value is equal to the measured value, the constant of the measuring instrument is 1

22. Characteristic curve

a curve indicating the functional relationship between the steady-state value of the output of the instrument and an input (other inputs are kept at the specified constant value)

23. Specified characteristic curve

under specified conditions, a curve indicating the functional relationship between the steady-state value of the output of the instrument and an input

24. Adjust the adjustment

to make the instrument work normally and eliminate the deviation to be suitable for the operation

user adjustment

Adjustments allowed by users

25. Calibration

under specified conditions, it is an operation to establish the relationship between the indicated value of measuring instruments or measuring systems or the value embodied by physical measuring tools and the known value corresponding to the measured value

26. Calibration curve

a curve indicating the relationship between the measured value and the actual measured value of the instrument under specified conditions

27. Calibration cycle calibration cycle

combination of up and down calibration curves between the limits of the calibration range of instruments and meters

28. Calibration table

refers to the data table form of the calibration curve

29. Traceability traceability

a feature of measurement results that can be linked with appropriate standards (usually international standards or national standards) through a continuous chain of comparisons

30. Sensitivity

divide the output change value of the instrument by the corresponding input change value

31. Accuracy

the consistency between the indicated value of the instrument and the measured [agreed] true value

32. Accuracy class

instruments and meters are classified according to the accuracy level

33. Limits of error

synonyms: maximum allowable error

the limit of instrument error specified by standards, technical specifications, etc

34. The basic error in is the same as the appearance of natural slate. The lines with deep shadows and well-defined edges are also called intrinsic error

indication error of instruments under reference conditions

35. Consistency

the consistency between the standard curve and the specified characteristic curve (such as straight line, logarithmic curve, parabola, etc.)

note: consistency is divided into independent consistency, end-based consistency and case-based consistency. When only called consistency, it refers to independent consistency

36. Independent consistency

adjust the calibration curve to be close to the specified characteristic curve, so that the maximum deviation is the smallest degree of consistency

the common term

1 measuring point (primary point)

refers to the point in the detection system or control system that is directly in contact with the process medium. Such as the pressure tapping point in the pressure detection system, the thermocouple and thermal resistance installation point in the temperature detection system, etc. The primary point can be on the process pipeline or on the process equipment

2 primary components (source components)

usually refer to the instrument processing parts installed on the primary point, such as the pressure tapping nipple in the pressure detection system, the thermometer boss in the temperature measurement system, etc

3 primary valve (pressure tapping valve)

refers to the valve installed on the primary component, such as the valve of the pressure detection system connected to the pressure tapping nipple, the valve connected to the outlet pipe of the orifice positive and negative pressure chamber, etc

4 primary element (sensor)

refers to the elements installed on site and in contact with the process medium, such as thermocouples, thermal resistors, etc

5 primary instrument

a kind of field instrument, which refers to the instrument installed on site and directly in contact with the process medium, such as spring tube pressure gauge, bimetal thermometer, differential pressure transmitter, etc

6 primary calibration (single calibration)

refers to the calibration of instruments before installation. According to the requirements of the code for construction and acceptance of Industrial Automation Instrument Engineering (gbj-86), in principle, each instrument should be calibrated once. The key point of adjustment is to check the indication error and variation of the instrument, adjust the proportional degree, integral time, differential time error, control point deviation, balance degree of the instrument, etc. Only instruments whose primary adjustment meets the requirements of the design or product instructions can be installed to ensure the quality of secondary adjustment

7 secondary instrument

refers to the general name of various instruments whose indicated value signal does not directly contact with the process medium. The input signal of the secondary instrument is usually the standard signal transformed by the transmitter. There are generally three kinds of standard signals received by secondary instruments: pneumatic signal; II type electric unit combination instrument signal,; Hi type electric unit combination instrument signal

8 field instruments

refers to the general term of instruments installed on site, including all primary instruments and secondary instruments installed on site

9 secondary calibration (secondary joint calibration, system calibration)

refers to the inspection of the entire detection circuit or automatic control system after the instrument is installed on site and the control room piping and wiring is completed and verified. It is also a comprehensive calibration before the instrument is delivered for formal use. The verification method is usually to add a signal in the detection link, and then carefully observe whether each instrument constituting the system works within the allowable error range. If the error is beyond the allowable range and the cause cannot be found, it is necessary to re debug all the instruments that make up the system

10 instrument machined parts

refers to the general term of all metal and plastic machined parts used for instrument installation, which occupies a special position in instrument installation

11 flow chart with control points

refers to the drawing that describes the automation content of the production process with the design symbols of the process detection and control system. It marks the installation position of the instrument in detail, is an important drawing to determine the primary point, is a comprehensive embodiment of the automatic control scheme and automation level, is also the basis of the automatic control design, and is a reference for construction installation and production operation