This regulation applies to the preliminary design, basic design, engineering design, construction drawing design of chemical automation, instrument position number compilation, P and ID (pipeline instrument flow chart), monitoring system schematic diagram and other design work. HG/T 20505-2000 Functional signs and graphic symbols of process measurement and control instruments (with clause explanation) HG/T20505-2000 standard download decompression password: www.bzxz.net

Industry Standard of the People's Republic of China
Functional Identification and Symbols for Process Measuring and Controlling Instrumentation HG/T20505-2000
Main Editor: China Chengda Chemical Engineering Company Approved by: State Administration of Petroleum and Chemical Industry Implementation Date: June 1, 2001 National Chemical Engineering Construction Standard Editing Center
(Former Engineering Construction Standard Editing Center of the Ministry of Chemical Industry) 2001 Beijing
1.0.1 This regulation applies to the preparation of instrument position numbers in the preliminary design/basic design, engineering design/construction drawing design of chemical automatic control, P&ID (piping instrument flow chart), monitoring system schematic diagram and other design work. This regulation and "Graphic Symbols and Text Codes for Engineering Design of Automatic Control" (HG/T20637.2) are the standing technical standards for graphic symbols in chemical automatic control design. 1.0.2 The relevant standards are as follows:
HG/T 20637.2
"Instrument Symbols and Signs"
"Graphical Symbols and Text Codes for Automatic Control Engineering Design" When implementing this regulation, it shall also comply with the requirements of the relevant national standards in force. 2
Instrument Function Sign
Composition of Function Sign
The instrument function sign consists of an initial letter and one or two to three subsequent letters. Examples are as follows: Example 1
PI--Function mark
P—First letter (indicating the measured variable)
I—Subsequent letters (indicating the readout function)
TIC Function mark
T—First letter (indicating the measured variable)
IC—Subsequent letters (indicating the readout function + output function)HIC-
Example 4FFICA
Function mark
—First letter (indicating the triggering variable)
Subsequent letters (indicating the readout function + output function) Function mark
First letter (indicating the measured variable + modifying letters) Subsequent letters (indicating the readout function + output function + readout function) Function mark
PD—First letter (indicating the measured variable with additional modifying letters)AHL-—Subsequent letters (indicating the readout function + modifying letters) The selection of the first letter and subsequent letters of the instrument function mark shall comply with the provisions of Article 3.1.1 of these Regulations. 2.1.2
2.1.3 The function mark only indicates the function of the instrument, not the structure of the instrument. If you want to realize the FR (flow recording) function, you can use a differential pressure recorder, or a single or multiple recorder. 2.1.4 The first letter of the function mark should correspond to the measured variable or the triggering variable, and it may not correspond to the processed variable. For example, for a control valve that adjusts the flow, the function mark used in the liquid level control system is LV, not FV.
A modifier letter can be added after the first letter of the instrument function mark, and the original measured variable becomes a new variable. For example, if D is added after the first letter P or T, it becomes PD or TD, and the original pressure and temperature become differential pressure and differential temperature.
2.1.6 One or two modifier letters can also be added after the subsequent letters of the instrument function mark to modify the readout function. For example, in the function mark PAH, the letter A is followed by H, which limits the alarm of the read function A to a high alarm.
2.1.7 The number of letters in the letter group of the function mark is generally not more than 4. In order to reduce the number of letters in the letter group, 1 (indication) can be omitted when an instrument is used to indicate and record the same measured variable at the same time. All letters of the instrument function mark should be capitalized. 2.2
Instrument position number
The instrument position number consists of two parts: the instrument function mark and the instrument loop number. The following is an example: FIC-116-
Instrument position number
FIC——Function mark
FFSHL-2-
One loop number
One instrument position number
Function mark
Loop number
The loop number can be composed of the process number plus the instrument sequence number, or it can be numbered by other specified methods. The examples are as follows:
Example 1 Instrument position number
FIC-116
Sequence number (generally two digits, three digits are also available) Process number (generally one digit, two digits are also available)FFSHL-2
Instrument position number 1
Sequence number (no process number)
2.2.3 Instrument position numbers are classified according to different measured variables. The sequence numbers in the instrument position numbers of the same type of measured variables in the same device (or process) should be continuous, and there can be blank numbers in the middle of the sequence numbers; instrument position numbers of different measured variables cannot be numbered continuously.
2.2.4 If there are more than two instruments with the same function in the same instrument loop, the instrument position number can be distinguished by adding a suffix letter (the suffix letter should be capitalized). For example, FT-201A and FT-201B indicate that there are two flow transmitters in the same loop; FV403A and FV-403B indicate that there are two control valves in the same loop. 2.2.5 When multiple detection elements of different processes share a display instrument, the position number of the display instrument does not indicate the process number, but only the sequence number: the position number of the detection element is a suffix added to the number of the shared display instrument. For example, the position number of the multi-point temperature indicator is TI-1, and the position number of its detection element is TE-1-1, TE-1-2, etc. 2.2.6 When an instrument is shared by two or more circuits, the instrument position number of each circuit should be marked. For example, when a dual 3
pen recorder is to record flow FR=121 and pressure PR-131, the instrument position number is FR-121/PR-131. 2.2.7 The instrument position numbers of multiple units are generally compiled in sequence, and the method of adding suffix letters to the same position number is not used. For example, the position numbers of the shaft temperature measuring instruments of compressor units 106-JA, 106-JB, and 106-JC are: TI1~TI-10 (106-JA), TI-11~TI-20 (106-JB), and TI-21~TI-30 (106-JC). 2.2.8 A loop code (also called loop mark) can be used to represent a monitoring loop. The loop code consists of the first letter and the loop number. For example, the loop code T-105 is used to represent the TI-105 detection loop; the loop code F-303 is used to represent the FIC-303 control loop.
2.2.9 In the design documents of the automatic control professional table category, the requirement for writing the instrument position number is that in general, no modifier letters are added to the subsequent letters of the function mark. For example, for the position number of the indication and control system with upper and lower limit alarms (interlocks), only PIA-101, TIS213 or FICA-502, LICS-201 are written, and the modifier letters H and L of the alarm (interlock) do not need to be written.
3. Instrument function letters and common abbreviations
3.1 Function letter code
The letter code of the instrument function mark is shown in Table 3.1.1 (the numbers in brackets in the table are annotation numbers). Table 3.1.15
Letter code
First letter
Measured variable or triggering variable
Analysis (3)
Burn, flame
Conductivity
Voltage (electromotive force)
Toxic gas or flammable gas
Time, time program
Water or humidity
Optional (4)
Optional (4)
Pressure, vacuum
Nuclear radiation
Speed, frequency
Multivariable (m)
Vibration, mechanical monitoring
Weight, force
Unclassified (13)
Event, state (（14））
Position, size
Main ()
Modifier
Ratio (ratio)
Rate of change (7)
Integration, accumulation
Safety (（10））
Readout function
Optional (4)
Detection element
Mirror, observation (5)
Optional (4)
Throttle hole
Connection or test point
Record, DCS trend record
Multi-function (12)
Unclassified (13)
Following letter (2)
Output function
Modifier
Optional (*)
Operator (8)
Optional (4)
Switch, Interlock
Transmission
Multi-function(（32）
Valve, damper, shutter
Unclassified(13)
Relay
Calculator, converter(15)
Driver, actuator
For selection(4)
High(6)
Low(6)
Medium, intermediate(6)
For selection(4)
Multi-function(12))
Unclassified(（13）
（1）“First letter” is generally a single letter representing the measured variable or the triggering variable (referred to as variable letter). After the first letter is supplemented with a modifier, the first letter is the first letter + modifier. (2) "Subsequent letters" can be one letter (readout function), two letters (readout function + output function), or three letters (readout function + output function + readout function), etc. as required.
(3) "Analysis (A)" refers to analysis items not specified in this table. When it is necessary to specify a specific analysis item, it should be indicated next to the graphic symbol (circle or square) representing the instrument position number. For example, when analyzing carbon dioxide content, CO2 should be marked outside the graphic symbol, and CO2 cannot be used to replace "A" in the instrument mark. (4) "For optional use" means that the meaning of this letter is not specified in the corresponding column of this table. Its meaning can be determined according to the needs of the user, that is, the letter represents one meaning as the first letter, and another meaning when it is used as a subsequent letter. It should be specified in the design legend of the specific project. (5) "Sight glass, observation (G)" refers to on-site instruments and sight glasses used to observe the process, such as liquid level gauges, sight glasses, etc. (6) \High (H)\, \Low (L)\, \Middle (M)\ should correspond to the measured value, not the signal value output by the instrument. H, L, and M are marked at the upper right, lower, and middle of the graphic symbol (circle or square) representing the instrument position number, respectively. (7) \Change rate (K)\ When combined with the first letter L, T. or W, it indicates the rate of change of the measured or triggered variable. For example, WKIC can represent the weight change rate controller
(8) "Operator (K)" indicates an automatic-manual operator set in the control loop, such as the automatic-manual operator in the flow control national route is FK, which distinguishes it from the manual operator HC.
(9) "Light (L)" indicates a separately set indicator light, which is used to indicate the normal working status. It is different from the "A alarm light" in the normal state. If the "L" indicator light is part of the loop, it should be used in combination with the first letter, for example, the indicator light indicating the end of a time period (time accumulation) should be marked as KQL. If it is not part of the circuit, it can be represented by a single letter "L", such as the indicator light of the motor. If the voltage is the measured variable, it can be represented as EL. If it is used to monitor the operating status, it can be represented as YL. Do not use XL to represent the indicator light of the motor, because the unclassified variable "X" is only used in limited occasions. The optional letters "N" or "o" can be used to represent the indicator light of the motor, such as NL or OL. (10) "Safety (S)" is only used for detection instruments or detection elements and final control elements for emergency protection. For example, "PSV" represents a pressure relief valve or cut-off valve that plays a protective role under abnormal conditions. It can also be represented by PSE for pottery doors or facilities that provide safety protection under accident pressure conditions, such as explosion membranes or explosion panels. (11) The first letter "Multi-variable (U)" is used to replace a combination of letters for multiple variables. (12) The subsequent letter "Multi-function (U)" is used to replace a combination of letters for multiple functions. (13) "Unclassified (X)" means that its meaning as the first letter or the subsequent letter is not specified. It can have any meaning as the first letter or the subsequent letter in different places. It is suitable for use only once or a limited number of times in a design. For example, XR-1 can be a stress recorder, while XX-2 can be a stress oscilloscope. When applying X, the meaning of the unclassified letter "x" is required to be indicated outside the instrument graphic symbol (circle or square). (14) Event, state (Y) indicates a control or monitoring response driven by an event (different from time or time program drive), and can also indicate existence or state. (15) "Relay (relay), calculator. Converter (Y)" is explained as follows: "Relay (relay) indicates an automatic device or device that is not a detection device in the circuit and whose action is driven by a switch or position controller. When indicating relay, calculation, and conversion functions, the specific function should be marked outside the instrument graphic symbol (circle or square) (usually in the upper right corner). However, it is not necessary to mark it when the function is obvious, such as the electromagnetic reading on the actuator signal line. 6
Commonly used combination letters of instrument function symbols are shown in Table 3.1.2. Table 3.1.2
First letter
Measured variable
or trigger
Burn flame
Conductivity
Flow ratio
Flow accumulation
Combustible gas
Time program
For selection
For selection
Pressure vacuum
Pressure difference
Nuclear radiation
Speed ​​frequency
Temperature difference
Multivariable
Unclassified
Event status
or existence
Position size
Detection index
【Alarm A (modified)
AAHAALAAHL
BAHBALBAHL
CAH CALCAHL
DAHDALDAHL
EAHEALEAHL
FALFAHL
Common combination alphabets
Relay final switch S (modified)
Indication record fingerless self-operated
AICARC
BICBRC
CICCRC
DICDRC
EIC ERC
FFAHFFALFFAHL
FFICFFRC
FQAHFOAL
IAHIALIAHL
JAHJALJAHL
LAH LALLAHL | |tt | |SAHSAL
TAHTAL
RICRRC
TDR TDAHTDALTDAHL
TDTTDIC
TDRCTDCTDCV
WR/WAHWAIWAHIWTWICWRCWC
YAHYAL
ZAHZALZAHL
Combination of irrigated variable and subsequent letters P, W, G: P detection point such as: AP, FP, PP, TP
W casing or probe such as: AW, BW, LW, MW, RW, TWG sight glass, observation such as: BG, FG, LG, etc.; local indicating instruments such as: IG, PG, LG, etc. YT
Other letter combinations:
Limiting orifice
Level control, transmission
Time or time program control
Temperature scanning indication
ASHASL
BSHBSLBSHL
CSHCSL
DSHDSL
ESHESL
FSHFSL
FFVFFSH FFSL FFSHL
FOVFOSH FOSL
ISHISL
JSHJSL
LSHLSLLSHL
MSHMSLMSHL
PSHPSLPSHL
PDSHPDSL
OSHQSLQSHL
SSHSSLSSHL
TSHTSL
TDSH TDSLTDSHL
WSHWSLWSHL
YSHYSL
3.2 Additional function symbols of the letter Y
3.2.1 When the letter Y is used as a successor letter to indicate the output function of a relay, calculator, converter, etc., an additional function symbol should be marked outside the graphic symbol (circle or square) with Y. Commonly used additional function symbols are shown in Table 3.2.1.
Average value
Additional function symbol table
Mathematical equation
M=X++X++X.bZxz.net
XI+X+...*+X.
M=X1-X2
M=XiX2
The output is equal to the algebraic sum of the input signals
The output is equal to the algebraic sum of the input signals divided by the number of input signals
The output is equal to the algebraic difference of the input signals
The output is proportional to the input
The output varies with the amplitude and duration of the input signal, and the output Proportional to the time integral of the input signal
The output is proportional to the rate of change of the input signalThe output is equal to the product of the two input signals
The output is equal to the quotient of the two input signals
The output is equal to the square root of the input signal (such as square root, cubic root, 3/2 root, etc.)
Nonlinear
or undefined
function
Time function
ContinuedTable 3.2.1
Mathematical equations
M=f(x)
M=xf(t)
M=f( t)
M=When XX2
M=XWhen XX2
M=X2When X≥X2
M=XWhen X≤H
M=HWhen X≥H
M=XWhen X≥L
M-LXAL
M=X±b
The output is equal to the nth power of the input signal
The output is equal to a nonlinear or undefined function of the input signal
The output is equal to the input signal multiplied by a certain time function or only equal to a certain time function
The output is equal to one of several input signals Maximum value
Output is equal to the minimum value of several input signals
Output is equal to input (when X≤H) or output is equal to upper limit value (when X≥H)
Output is equal to input (when X≥L) or output is equal to lower limit value (when X≤L)
Output is inversely proportional to input
Output is equal to input plus (or minus) an arbitrary value (bias value)
Continued Table 3.2.1
Mathematical equation
Output = f(input)
3.2.2 Additional function Symbol application examples are shown in Table 3.2.2. Table 3.2.2
Names of relays, calculators,
converters
Arithmetic unit
Selector
Converter
Function generator
The type of output signal is different from the type of input signal,* as follows:
E-voltage
B-binary
1-current
H-hydraulic pressure
P-air pressure
0-electromagnetic wave
A-analog
R resistance
D-digital
Table of examples of application of additional function symbols
Conventional instruments
Common abbreviations for instruments
Common abbreviations other than instrument function symbols are shown in Table 3.3.1. Table 3.3.I
An.log signal
Almiating current
Analog/Digital
Auiomatic/Manual
AADgate
Average
Chromatograph
Common English abbreviations
Derivative control mode
Digital signal
Digital/Anaiog
D.eet current
Suhitract
Direet-acting
Voltage signal
Electric signal
Ele-ctnicmagetic flowmeter
El-utric supply|| tt||Emergency shutdown
Fail closed
Feedforward control mode
Feedforward unit
Fail indeterminate
Fail locked
Fail open|| tt||Hrdraulice signal
Highest(Higher)
Highest select
Electric current signal
Interlock
Integrate
Instrument air|| tt||Intemal orifice plate
Instrument panel
Analog signal
AC
Analog/digital
Automatic/manual
“AND” gate
Differential control method||tt ||Digital signal
Digital/analog
Direct current
Positive action
Voltage signal
Electrical signal
Electromagnetic flowmeter||tt ||Emergency stop
Fault off
Feedforward control mode
Feedforward unit
Any position when fault occurs
Hold position when fault occurs·||tt ||Fault open
Hydraulic signal
Highest (higher)
Current signal
Instrument air
Built-in orifice
Instrument plate
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