GB/T 2625-1981 Graphic symbols and text codes for process detection and control flow charts
Some standard content:
National Standard of the People's Republic of China Graphical Symbols and Text Codes for Process Detection and Control Flowcharts GB 2625 8T 1.1 This standard is applicable to chemical, petroleum, metallurgy, electric power, light industry, textile, building materials and other industries, and aims to specify a unified representation method for instrument devices used in process detection and control flow charts. The graphic symbols and text codes specified in this standard can also be used for other design documents and technical documents. 1.2 The marking of instrument devices is composed of graphic symbols and text codes. 1.3 Under the conditions that do not violate the provisions of this standard, various departments may make supplementary provisions. 2. Definitions The following definitions apply only to this standard. 2.1 Process Any operation or series of operations that can cause a change in the state, composition, size or other characteristics that can be defined by data. 2.2 Function
The action or function performed by the instrument
2.3 Loop
A combination of one or more related instruments used to measure, control, or measure and control process variables. 2.4 Ballon
A circular symbol used to represent an instrument or an instrument logo. 2.5 Point of measurement
The point where a process variable can be measured.
2.6 Test point
A test connector to which the instrument is not permanently connected. It is used for temporary, intermittent or post-order connection of the instrument. 2.7 Detecting element, sensor, primary element An element that directly responds to the value of the measured variable and converts it into a form suitable for measurement. 2.8 Transmitter
An instrument that receives the measured variable with the help of a detecting element and converts it into a standard output signal. A transmitter may or may not include a detecting element.
2.9 Relay
An instrument that accepts information in the form of one or more instrument signals, changes the information when necessary, and outputs one or more output signals. It is a general term for converters, calculators, signal selectors, amplifiers, etc., but does not include switches, regulators, etc. 2.10 Calculator Computing instrument. An instrument that completes one or more calculations, logic, or calculation and logic functions, and outputs one or more signals. 2.ll Converter SignalCouvertcr
An instrument that accepts information in the form of instrument signals, changes the information in the form of signals, and outputs a signal. 2.12 SignalSelector SignalSeleutor An instrument that automatically selects the highest or lowest input signal from two or more input signals. Issued by the State Administration of Standardization
Proposed by the State Administration of Instrument Industry
Implemented on March 1, 1982
Initiated by Shanghai Industrial Automation Instrument Research Institute 2.13 Alarm
CB2625-81
When an abnormal condition exists, it emits a sound, light or both signal to attract attention. The instrument with the above function is called an alarm. 2.14 Scan
Sequentially conduct automatic sampling of several input signal traces. 2.15 Pilot light
A light indicating that the process or equipment is in a normal state. It is different from the alarm light indicating an abnormal state. Note: The pilot light may be accompanied by an audible signal.
2.16 Switch
A device that connects, disconnects or changes one or more circuits, not a regulator, relay or regulator. This term also applies to the function performed by a switch. 2.17 Controller An instrument that automatically operates to control a controlled variable. 2.18 Operator A device that can manually select between manual and automatic control of a controlled variable. 2.19 Manual operator A device that has only manually adjusted outputs and is used to operate one or more remote devices. 2.20 Setpoint An input variable used to set the desired value of a controlled variable. This input variable value can be set manually, automatically or by a program. 2.21 Final control element, correcting unit An instrument that responds to a signal to change the value of a manipulated variable. It consists of an actuator and a regulating element. 2.22 Control valve An actuator that responds to a signal to change the flow of a fluid. 2.23 Actuator An actuator element The part of an actuator that responds to a signal from, for example, a regulator to adjust the regulating element. 2.24 regulating mechanism correcting element part of the actuator, which is used to directly change the value of the manipulated variable. 2.25 instrument panel, board
a component composed of one or more screens, cabinets, tables or racks on which instruments are mounted. 2.26 board-mounted
instruments installed on a panel accessible to operators during normal use are called panel-mounted. 2.27 mounted bchind the board instruments installed in an area of the instrument panel that is inaccessible to operators during normal use are called behind-the-board installations. Note: Behind-the-board installations include installations within the board.
2.28 local
the location of instruments that are neither on the board nor behind the board, usually refers to the vicinity of the measuring point or the operating point. 2.29 local board
usually refers to instrument panels near process equipment subsystems or partitions. 2.30 Multiple-pen recorder (multiple-pointer indicator) is a recorder (indicator) suitable for multiple input signals. Each input signal is provided with a separate recording pen (pointer) or other recording device (indicator).
2.31 Multiple-channel recorder (indicator) is a recorder (indicator) suitable for multiple input signals. Different input numbers are connected to the measurement line of the recorder (indicator) in sequence, so the recorder (indicator) records (indicates) the values of the input signals in sequence. Graphic symbols
3.1 Measuring point
GB2625—81
3.1.1 The measuring point is the starting point of the line from the process equipment contour line or pipeline line to the instrument circle. "No specific graphic symbols are generally shown in Figure 1.
3.1.2 When it is necessary to mark the position of the measuring point in the process equipment, the line should be drawn to the appropriate position within the outline of the process equipment, and a small circle symbol with a diameter of about 2mm should be added at the starting point of the line, as shown in Figure 2. Figure 2
3.1.3 The position of the measuring base point should be correct in terms of function and process sequence, but it does not indicate its exact position. 3.2 Detection element
In the flow chart, the detection element is generally No indication is required. If necessary, it can be indicated by the instrument circle and instrument position number or the graphic symbols listed in Table 1.
Detection element name
Thermal resistor
Embedded in the pipeline
Detection element*
Pressure tap
(without hole plate)
Graphic symbol of detection element
Graphic symbol
Mark in the circle
Instrument position number
Detection element name
Venturi tube
*Embedded in the pipeline means that the detection element occupies a pipeline. 3.3 Line
GB2625-81
Graphic symbols
3.3.1 The symbols of machine connection lines and instrument energy lines (including flushing fluid sources) are thin solid lines. Note: ① When it is necessary to classify the instrument energy categories, the following abbreviations can be marked on the energy line symbols: As
Air source
Other flushing thin source
Hydraulic Source
Dual air source
Steam source
Continued Table 1
②The energy rating of the instrument can be added after the energy abbreviation letter, for example, AS1.4 is an air source of 1.4kgf/cm, ES21DC is a 2+V DC power supply.
3,3.2 For instrument circular diagrams used only for instrument marking, the lines connected to the process equipment contour line or pipeline line are thin solid lines. 3.3.3 General unclassified signal lines are thin solid lines. 3.3.4 When it is necessary to distinguish the types of signal lines, the graphic symbols listed in Table 2 should be used. Table 2
Types of signal lines
Telecommunication wires
Pneumatic signal lines*
Hydraulic signal lines
Electromagnetic or electromagnetic
Signal lines**
The dashed line is at an angle of 00 to the solid line
* Air is not used as the medium of the pressure signal line. The gas used is indicated on the gas signal line or in other ways. *Electromagnetic phenomena include heat, radio waves, nuclear radiation and light. GB2625-81
3.3.5 The line from the measuring point or detection element symbol to the instrument circle representing the instrument, except for the line indicating the mechanical connection, should be a signal line.
3.3.6 When it is necessary to indicate the direction of information transmission, a header should be added to the signal line, as shown in Figure 3 (taking the general signal line as an example). Figure 3Www.bzxZ.net
3.4 Instrument Circle
3.4.1 The instrument circle is a thin solid circle with a diameter of 10mm. It can be appropriately enlarged or reduced when necessary. When the instrument position number is too long and the circle cannot accommodate it, it can be disconnected, as shown in Figure 4. Figure 4
3.4.2 An instrument circle can be used to represent a meter, a combination of multiple meters in a circuit, an instrument connection and its accessories, or an instrument to mark the position number of a measuring point.
Sometimes, a meter is also represented by two or more instrument circles. 3.4.3 When it is necessary to distinguish the installation location of the meter, the instrument circle should be represented as shown in Table 3. Table 3
Installation position
On-site installation
Panel installation
Behind-panel installation
On-site panel installation
On-site panel installation
Graphic symbols
Embedded in pipelines
Method: When multi-level control requires different control levels of instrument panels or when there are necessary marking panels, words or numbers can be marked in the middle position outside the instrument circle.
GB2625-81
3.4.4 Instruments that process two or more variables (when the multi-variable letter U is not used) (such as multi-pen recorders or multi-point recorders) or instruments that process one variable but have multiple functions can be represented by two or more tangent instrument circles, as shown in Figure 5. Figure 5
3.4.5 In the case of 3.4.4 above, when the two measuring points are far apart on the drawing and are not on the same drawing, if necessary, two tangent solid circles and dotted circles can be used to represent them near the two measuring points, as shown in Figure 6. Figure 6
3.5 Actuator
3.5.1 The graphic symbol of the actuator is a combination of the graphic symbols of the actuator and the regulating mechanism. 3.5.2 Actuator
3.5.2.1 The general graphic symbol of the actuator that does not distinguish the type is a thin solid circle with a diameter of about 5 mm and a thin solid line connected to the graphic symbol of the regulating mechanism, as shown in the figure.
3.5.2.2 When it is necessary to distinguish the type of actuator, the graphic symbols listed in Table 4 should be used. Table 4
Actuator types
Diaphragm actuator with spring
Diaphragm actuator without spring
Piston actuator
Electric motor actuator
Electromagnetic thermal actuator
Graphic symbols
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3.5.2.3 When it is necessary to indicate the additional devices of the actuator, the graphic symbols listed in Table 5 should be used. No.
Additional device name
Combination of actuator and handwheel (taking
diaphragm actuator with spring as an example
Combination of actuator and valve positioner (taking
diaphragm actuator with elastic tube as an example)
Combination of actuator and valve positioner with conversion (taking
diaphragm actuator with elastic as an example)
Actuator with manual reset device (taking electromagnetic actuator as an example)
Actuator with remote reset device (taking electromagnetic actuator as an example) || tt||3.5.3 Adjustment mechanism
Graphic symbols
Top or side installation
All are indicated by the standard
method
3.5.3.1 The universal graphic symbol of the adjustment mechanism regardless of the type is an equilateral triangle with a side length of about 5mm, as shown in Figure 8,7
3.5.3.2 When the adjustment mechanism is a valve, the graphic symbols of various types shall comply with the relevant provisions of the national standard. Before the national standard for valve symbols is issued, valves for various types of nozzles may adopt the graphic symbols in Table 6 or the relevant provisions of various departments. Serial number
Other types of valves*
GB 2625—81
Graphic symbols
Various commonly used valves can use the graphic symbols in Table 7 or the relevant regulations of various departments. Serial number
Type of valve
Spherical, straight and thin valves such as butterfly valves, air doors, shutter valves
Xuan plugs, ball valves
*The type of valve should be explained in the legend.
Graphic number
GB 262581
3.5.4 When it is necessary to indicate the status of the instrument when the power supply is interrupted, the additional graphic symbols in Table 8 may be used. No.
Regulation status
When the power supply is interrupted, the valve
When the power supply is interrupted, the valve
retains the original position
When the power supply is interrupted, the valve
retains the original position and is allowed to drift in the open direction
When the power supply is interrupted, the valve
retains the original position and is allowed to drift in the closed direction
Three-way valve
When the power supply is interrupted, the fluid flow direction
Four-way valve When the valve energy is interrupted, the fluid flow direction will be indicated in the figure. Take the diaphragm two-way regulating valve as an example. Take the diaphragm two-way regulating valve as an example. Take the diaphragm two-way regulating valve as an example. Take the diaphragm two-way regulating valve as an example. Take the diaphragm three-way regulating valve as an example. The arrow indicates the fluid flow direction. When necessary, A, B, and C can be annotated next to each symbol for identification. And indicate the passage connected. Take the diaphragm four-way regulating valve as an example. The arrow indicates the direction of fluid flow. When necessary, A, B, C, D can be marked beside each passage symbol for identification, and the connection is marked as a passage, such as BA, D_C. GB 2625-81 3.5.5 The graphic symbols for self-adjusting valves are shown in Table 9. No.
3.6 Others
Bai Li type regulating valve type
Bai Li type liquid level regulating valve
(mechanical connection)
Bai type pressure regulating valve
Self-operated differential pressure regulating valve
Self-operated temperature regulating valve
3.6.1 Graphic symbols of other instruments and devices are shown in Table 10. No.
Name of instrument and device
Indicator light
Circuit board or matrix wiring board| |tt||Air blowing device or flushing device
Graphic symbol
Graphic symbol
Circular diameter is about 10mm
Side length is about m
Side length is about Bmm
Only installed and device called
Remote logic element
(AND gate)
Logic element
(OR gate)
Undetermined or complex
Logic optical element
Isolation device
GB 2625-—81
Character symbol
3.6.2 When it is necessary to distinguish the connection form of the level instrument, the graphic symbols in Table 11 can be used. No.
Type of level instrument
Integrally installed liquid level instrument
Liquid level instrument with two connecting pipes (external floating type)
Liquid level instrument with a single connecting pipe (internal floating type)
Graphic symbol
Continued Table 10
Numbers in the box
{such as 1 -
is the detailed drawing number
Type of level instrument
Differential pressure liquid level instrument
Differential pressure liquid level instrument
(single
flange instrument with balance)
Level instrument
4.Text code
4.1 Instrument position number
GB2625-81
Graphic symbols
Continued Table 11
4.1.1 Instrument position number consists of two parts: letter code and digital number, separated by a short dash. If necessary, a suffix may be added after the digital number.
4.1.2 Letter code consists of the first letter representing the variable to be measured or the initial variable and the subsequent letter representing the function. Unless it is the case described in Note (4) of Table 13 of 4.2.1, all letters are capital letters. 4.1.3 Digital number consists of area number and loop number. In general, the area number is one digit and the loop number is two digits. If necessary, the number of digits of the area number and loop number can be increased or decreased. In some cases, the area number can also be omitted. The digital number is Arabic numerals.
Note: The area number can represent train, section, device, system, equipment, base, or even both of them. 4.1.4 The suffix may be an uppercase English letter or an Arabic numeral followed by a hyphen. 4.1.5 If necessary, other arrangements of digital numbers and suffixes may be used. 4.1.6 Examples of instrument position numbers (temperature recorder and regulator) are shown in Table 12.
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