HG/T 20637.2-1998 Graphic symbols and text codes for automatic control engineering design HG/T20637.2-1998 Standard download decompression password: www.bzxz.net

Symbols and Identiers for Engineering Design of InstrumentationHG/T20637.2-1998
Prepared by: China Wuhuan Chemical Engineering CompanyApproved by: State Administration of Petroleum and Chemical IndustryImplementation date: January 1, 1999Prepared by:
An TiefuSun Jianwen
Reviewed by:
Gao XinWang DazhengSong Xiaoxian
Duan Benxian
1 General Provisions
In order to meet the needs of engineering design of automatic control industry and standardize and normalize engineering design documents, this regulation is specially prepared.
1.0.2This regulation applies to the drawing of graphic symbols such as instrument loop diagrams, instrument location diagrams, instrument cable tray layout diagrams, instrument cable (pipe cable) and tray layout diagrams, field instrument wiring diagrams, logic diagrams, semi-simulation flow charts, DCS process displays, and common electrical equipment for instruments in the design of automatic control engineering for chemical plants. 1.0.3The relevant standards are as follows:
IEC617
HG20505
Binary logic diagrams for process operations
Instrument loop diagrams
Graphic symbols for process displays
Part 12: Binary logic units
When implementing this regulation, the text codes and graphic symbols for process detection and control systems shall also comply with the provisions of the relevant current national standards. 227
2 Graphic symbols for instrument loop diagrams
2.1 Overview
The graphic symbols for instrument loop diagrams are applicable to instrument loop diagram files for automatic control engineering designs that use conventional instruments or distributed control systems, to indicate the instrument functions for process detection and control systems, as well as the installation locations of junction boxes, pipe boxes, terminal boards, and through-plate connectors, the connection relationship between signal lines between instruments, and the connection of energy lines. 2.1.2 Instrument loop diagrams should be drawn using double-line drawing. 2.2 Graphic symbols
The graphic symbols for instruments should include descriptions of the connection terminals and energy sources (power supply, gas source, hydraulic source). 2.2.1
2.2.2 The size of graphic symbols such as terminal boards or through-plate connectors shall be determined by the designer based on needs and drawing size. The graphic symbol of the instrument signal shielding line is represented by a thin solid line ellipse, as follows: 2.2.3
The graphic symbols of terminal boards or through-plate connectors are represented as follows: 2.2.4
Terminal board or junction box number
Through-plate connector or connecting box number
2.2.5The instrument terminal or channel number can be letters, numbers or both, and should be the letter and number number specified by the manufacturer. The graphic symbols are represented as follows:
Instrument terminal or channel number
2.2.6The graphic symbol of the instrument system energy is represented as follows: The power supply box and power supply circuit number should be marked, and the power supply category and specification can be marked. ES220V
Air source can be marked with air source category and pressure.
AS0.14MPa
Hydraulic source can be marked with hydraulic source pressure.
2.3.1 The example of instrument loop diagram using pneumatic instruments is shown in Figure 2.3.1. 2.3.2 The example of instrument loop diagram using electric instruments is shown in Figure 2.3.2. 2.3.3
The example of instrument loop diagram using DCS system is shown in Figure 2.3.3229
ONIEMNOO
600-31a/216-31
ONO Club Wine
100011080
3 Graphic symbols of logic diagram
3.1 Overview
3.1.1 Graphic symbols of logic diagram are applicable to the drawing of binary interlocking and program control systems such as starting, operation, alarm and parking of production processes and equipment in automatic control engineering design. They are also applicable to the use of logic diagrams to represent logical functions. They can also be used to represent physical devices that can perform these logical functions and can be used for any kind of hardware. 3.2 Composition of symbols
The symbol consists of a box or a combination of boxes and one or more limiting symbols. Box
Input line
Optimal position of the general limiting symbol
Output line
General limiting symbol optional position
Note: 1. Input and output lines must be attached when the symbol is used. 2. A single asterisk (*) indicates the allowed position of the limiting symbol related to input and output. 3. The general limiting symbol is not required only when the function of the unit is completely determined by the input and/or output limiting symbols. 4. The size of the symbol can be determined according to the space required for internal marking and the number and spacing of input/output lines. 3.2.2 Letters marked outside the symbols (I\input" and 0\output\) are not part of the symbols, but are only used as references to explain the input and output terminals of the logic elements. 233
3.3 Use of symbols
3.3.1 The logic system can be described using only the most basic logic block diagram composed of "basic" symbols. In order to make the drawn logic system diagram clear, easy to understand, and simple, optional non-"basic" symbols can also be used. The graphic symbols framed by bold lines in Article 3.4 of these regulations are all "basic" symbols. 3.3.2 The depth of the logic diagram depends on the intended use. In order to make the logic diagram more clear, some auxiliary, actually non-logical information may be included. Such as reference file logos, bit numbers, terminal markings Etc. 3.3.3 In Section 3.4 of this Regulation, a logic symbol with three inputs - 11, 12 and 13 - is shown, which represents a logic function with two or more input signals. 3.3.4 Signal flow is represented by signal flow lines that express logical relationships. The usual flow direction is from left to right or from top to bottom. For clarity, arrows may be added to flow lines, but for flow lines that are different from the usual flow direction mentioned above, arrows must be added to indicate their flow direction.
3.3.5 The consequences of power failure to any logic component or the entire logic system should be considered. In this case, power on or off can be used as a necessary condition for the logic signal to be input to the system or individual logic elements. For memory devices, power considerations can be applied in the above method or as described in 3.4.7(b) As shown in Article 3.4.7(c), Article 3.4.7(b) 1 of this Regulation has already specified how to use symbols to indicate that the memory device disappears when the power fails. Therefore, the logic feedback symbol should not be used to indicate the memory device, and the following symbols should not be used. .01
The consequences of power restoration should also be considered.
3.4 ​​Graphic symbols
The provisions for representing binary logic symbols are shown in Table 3.4. 234
* Detailed description inside, expressed by
mathematical symbols and values ​​(see
Explanation)
Provisions for representing binary logic symbols
Input signal to logic program
Output signal to logic program
When interlocking||tt ||Action status
Contact status when a fault occurs
Interlock reason
Contact position
See Figure 3.5.4
Position number or device name
See Figure 3.5.4
Only when 11, I2, and 13 meet
If the liquid level in the suction tank is high and the discharge valve is open, the inputs are all in "1" state, and the logic start pump output O1 is "1\ state
Suction tank liquid level is high
Discharge valve is open
Only when one or more of the logic
inputs 11, 12, and 13 are
"1" state, the logic output 01 is
"1\ state
Only when 11.12 and 13 logic
Start the pump
If the cooling water pressure is low or the bearing temperature is high, then stop the pressure water pressure low
Stop the compressor
High bearing temperature
a) If two and only two storage bins are in use, the input is in the "1\ state. The mixer is started only when the value represented by the limited derivative number is met. The logical output
01 is in the "1" state. The following limited mathematical titles must be used and the corresponding values ​​must be specified:
a) =equal to
b)half not equal to
c)<less than
red bin in use
blue bin in use
white bin in use
yellow bin in use
mixer
1)not gate (inverter)
2)not gate at input endbzxz.net
3)not gate at output end
d)>greater than
enot less than
subnot greater than
g)<less than or equal to
(equivalent to f)
h)≥greater than or equal to
(equivalent to e)
Only when the logic input 11
is in the "1" state, the logic output 01
is in the "0" state
Only when the logic input 11
is in the "1" state, the internal logic output
is on the contrary in the "0\ state
Only when the internal logic output
is in the "1" state, the external logic
output 01 is on the contrary in the "0" state||tt ||When the logic input 11 is in the "1" state, the logic output O1 immediately
is in the "1\ state and continues to be in the "1\
state until the logic input 12 is
in the "1" state, then the logic output 01
is in the "0\ state and continues to be in the "0\ state, unless the input
11 is in the "1" state again, in which case the output
will not be displayed until the output 02 is not used and the output 01 is in the "1" state again.
b) The reaction stops only when at least two safety devices require stopping
Device triggers
2# device triggers
3# device triggers
Device triggers
Device triggers
If both 1# burner and 2# burner are not opened, the fuel gas is cut off
1# burner opens
2# burner opens
1# burner opens
2# burner opens
Fuel gas
Fuel gas
If the tank pressure becomes high, the tank is vented and depressurized, and the venting continues regardless of how the pressure changes afterwards. The venting can only be stopped by manually operating the manual switch HS-1 when the pressure is not high. The tank venting stops and the compressor can be started
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