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1、BRITISH STANDARD BS 1646-2: 1983 Symbolic representation for process measurement control functions and instrumentation Part 2: Specification for additional basic requirements UDC 53.08:681.2:003.62 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:10:45 GMT+00:00 2006, Uncontrolled Copy, (c)
2、 BSI BS 1646-2:1983 This British Standard, having been prepared under the direction of the Industrial-process Measurement and Control Standards Committee, was published under the authority of the Board of BSI and comes into effect on 30 November 1983 BSI 01-1999 The following BSI references relate t
3、o the work on this standard: Committee reference PCL/4 Draft for comment 78/31228 DC ISBN 0 580 13627 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Industrial-process Measurement and Control Standards Committee (PCL/-) to Technical C
4、ommittee PCL/4 upon which the following bodies were represented: Association of Consulting Engineers Beama Transmission and Distribution Association British Industrial Measuring and Control Apparatus Manufacturers Association (BEAMA) Energy Industries Council Institute of Measurement and Control Ins
5、titution of Gas Engineers Ministry of Defence Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:10:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1646-2:1983 BSI 01-1999i Contents Page Committees responsibleInside front cove
6、r Forewordii 0Introduction1 1Scope and field of application1 2References1 3Definitions1 4Letter code1 5Instrument signal lines3 6Primary elements, correcting elements, and actuating elements3 7Local control panels5 8Signal modifiers, analogue6 9Binary logic7 10Action of binary signals on analogue si
7、gnals7 Table Letter code for identification of instrument functions2 List of referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:10:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1646-2:1983 ii BSI 01-1999 Foreword This British Standard has been prepared under the
8、 direction of the Industrial-process Measurement Control Standards Committee and is technically equivalent to the International Organization for Standardization (ISO) draft international standard ISO/DIS 3511/2 “Process measurement control functions and instrumentation Symbolic representation, Part
9、2: Extension of basic requirements”. The decision to publish now rather than await the publication of the corresponding ISO standard, recognises the urgent need of the industry for a standard with worldwide application based on an international text. It is anticipated that any differences with the f
10、inally published ISO version will be of a minor nature. This standard incorporates minor editorial corrections to the ISO draft which have been submitted by the British Member Body to the ISO Technical Committee. For ease of production the text of the draft international standard has been used for t
11、his British Standard; some terminology and certain conventions are not identical with those used in British Standards. The rectangular symbols in accordance with IEC 117-15, referred to in clause 9, are identical with those given in BS 3939-21. A British Standard does not purport to include all the
12、necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-reference International standardCorresponding British Standard IEC 117BS 3939 Graphical sy
13、mbols for electrical power, telecommunications and electronic diagrams (Technically equivalent) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 8, an inside back cover and a back cover. This standard has been updated (see copyright date) and
14、may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:10:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1646-2:1983 BSI 01-19991 0 Introduction This British Standard has been devised
15、to provide a universal means of communication among the various interests involved in the design, manufacture, installation and operation of measurement and control equipment used in the process industries. Requirements within the industries vary considerably; in recognition of this, this British St
16、andard is presented in several parts, as follows: Part 1: Basic requirements (directed towards the needs of those employing comparatively simple measurements and control means); Part 2: Extension of basic requirements; Part 3: Detailed symbols for instrument interconnection diagrams; Part 4: Basic s
17、ymbols for process computer, interface, and shared display/control functions1). The four parts together are intended to: a) meet the requirements of those, possibly employing more sophisticated measurement and control means, who may wish to depict such aspects as the measurement techniques embodied
18、in a particular instrument, or the means hydraulic, pneumatic, electrical, mechanical used for its actuation; b) provide standard symbolic representation for process measurement control functions and instrumentation. These symbols are not intended to replace graphic symbols for electrical equipment
19、as contained in IEC Publication 117. 1 Scope and field of application This Part of BS 1646 is an extension of Part 1, which is limited to identification of instrument functions. It includes additional symbols and is intended for the communication of measurement and control functions among instrument
20、 specialists and other engineers involved with vessels, piping, layout design and operation. The symbols are used on piping and instrumentation diagrams and engineering line diagrams. 2 Reference IEC 117-15, Recommended graphical symbols; graphical symbols Part 15: Binary logic elements. 3 Definitio
21、ns The definitions given in BS 1646-1 equally apply to this Part of BS 1646. The following definition also applies: 3.1 sensing element that part of an instrument loop that first senses the value of a process variable and that assumes a predetermined and intelligible state or output NOTEThe sensing
22、element may be separate from or integral with another functional element of a loop, but should be given an individual tag number only if it is separate. Examples: Where a direct-connected pressure transmitter has an integral pressure-sensitive element, the combined element and transmitter assembly s
23、hall be tagged PT. Where an external pressure cell is connected to a transmitter, the pressure cell shall be tagged PE and the transmitter shall be tagged PT. 4 Letter code 4.1 Identifying letters The function of the instrument shall be defined by a letter code included within the instrument symbol
24、circle. 4.2 Basis for the letter code The letter code is built up similarly to the letter code for basic symbols given in BS 1646-1 but the table extends the letters available for use. 1) At present at the stage of draft. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:10:45 GMT+00:00 2006
25、, Uncontrolled Copy, (c) BSI BS 1646-2:1983 2 BSI 01-1999 Table Letter code for identification of instrument functions NOTEEntries in normal type are identical with the entries in the Table of BS 1646-1. Entries in italics indicate the supplementary symbols. 1234 First letteraSucceeding lettera Meas
26、ured or initiating variableModifierDisplay or output functions AAlarm BDisplay of state (e.g., motor running) CControlling DDensityDifference EAll electrical variablesbSensing element FFlow rateRatio GGauging, position or length HHand (manually initiated) operated IIndicating JScan KTime or time pro
27、gramme LLevel MMoisture or humidity NUsers choicecUsers choicec OUsers choicec PPressure or vacuumTest-point connection QQualityb for example AnalysisIntegrate or totaliseIntegrating or summating Concentration Conductivity RNuclear radiationRecording SSpeed of frequencySwitching TTemperatureTransmit
28、ting UMultivariabledMultifunction unit VViscosityValve, damper, louvre, actuating element, unspecified correcting unit WWeight or force XUnclassified variablescUnclassified functions (for example cathode-ray tube) YUsers choicecComputing relay, relay ZEmergency or safety acting a Upper case letters
29、shall be used for the measured or initiating variable and succeeding letters for display or output function. Upper case letters are preferred for modifiers, but lower case letters may be used if this facilitates understanding. b A note shall be added to specify the property measured. c Where a user
30、has a requirement for measured or initiating variables to which letters have not been allocated and are required for repetitive use on a particular contract, the letters allocated to “Users Choice” may be used provided that they are identified or defined for a particular measured or initiating varia
31、ble and reserved for that variable. Where a user has a requirement for a measured or initiating variable that may be used either once or to a limited extent the letter X may be used provided that it is suitably identified or defined. d The letter U may be used instead of a series of first letters wh
32、ere a multiplicity of inputs representing dissimilar variables feed into a single unit. NOTEWhere it is necessary to denote HIGH or LOW, the qualifying letters H or L may be used in association with the instrument symbol. Other letters may be used, for example for deviation, for rate of change, etc.
33、 but must be defined on the drawing rather than the table. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:10:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1646-2:1983 BSI 01-19993 5 Instrument signal lines 5.1 Electric (E) 5.2 Pneumatic (A) 5.3 Hydraulic (L) 5.4 Capillary 5.5 Conducted
34、 radiation (radio waves, visible light) 6 Primary elements, correcting elements, and actuating elements NOTEIn cases where it is necessary to use detail symbols in functional diagrams the symbols should be as given in BS 1646-3, simplifying if possible. Examples are as follows. 6.1 Flow primary elem
35、ents 6.1.1 Orifice plate 6.1.2 Venturi tube 6.1.3 Nozzle 6.1.4 Variable area meter 6.1.5 Turbine meter 6.1.6 Volume meter general Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:10:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1646-2:1983 4 BSI 01-1999 6.1.7 Any other flow primary eleme
36、nt 6.2 Level instrument connections 6.2.1 Integrally mounted instrument, for example welded-on type 6.2.2 Instrument with single connection, for example internal-float type 6.2.3 Instrument with two connections, for example external displacer type 6.2.4 Tank gauge-float type 6.2.5 Tank gauge-float t
37、ype, top-mounted 6.2.6 Level control valve mechanical linkage 6.3 Pressure regulators, self-actuated 6.3.1 Pressure regulator with internal tap 6.3.2 Pressure regulator with external tap 6.3.3 Differential-pressure regulator with external taps Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 0
38、3:10:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1646-2:1983 BSI 01-19995 6.4 Actuating elements (where it is desired to show the type of actuating element) 6.4.1 Diaphragm actuator 6.4.2 Diaphragm actuator, pressure-balanced 6.4.3 Rotary motor actuator 6.4.4 Solenoid actuator (Preferred side r
39、elationship 1:2) 6.4.5 Piston actuator (Preferred side relationship 1:2) 6.4.6 Solenoid actuator with reset (manual) 6.4.7 Solenoid actuator with reset (remote electrical) 7 Local control panels Instruments on local control panels can be specified by an additional horizontal line across the symbol.
40、The particular panel can be identified by a note alongside the symbol, for example: CompressorPressure indicator on the compressor panel ServicesFlow recorder on the services panel Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:10:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1646-2:19
41、83 6 BSI 01-1999 8 Signal modifiers, analogue Lower case letter designations (for example a1, a2, etc.) are standardized values of signals, shown for descriptive purposes only. They are not part of the symbol. Other arithmetic functions may be similarly treated. Upper case letters (for example Z) re
42、present signals without specific values. 8.1 Addition For example, flow signals 8.2 Root extraction (square root) For example, flow signal 8.3 Limitation of output when a hand-set high-limit value is reached (same as selecting lower signal) For example, temperature controller signal when a1 a2 then
43、Z = a1 8.5 High-signal selector For example, pressure signals when a1 $ a2 then Z = a1 when a1 a2 then Z = a2 when a1 # a2 then Z = a1 8.7 Reversing relay For example, pressure signal Z = 1 a 8.8 Volume booster For example, level controller signal Licensed Copy: sheffieldun sheffieldun, na, Fri Nov
44、24 03:10:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1646-2:1983 BSI 01-19997 8.9 Gain or attenuation relay For example, flow signals 8.10 Characterizing relay f (x) For example, flow signal 8.11 Digital-to-analogue or analogue-to-digital signal converter For example, pressure signals 8.12 On-o
45、ff relay 1-0 For example, temperature analogue input signal with binary output signal 8.13 Bias relay , + or , representing relays respectively for plus-or-minus adjustability, for addition, or for subtraction. For example, flow signal, with adjustable plus or minus bias, k 9 Binary logic The basic
46、elements are “and”, “or”, “not” and “delay elements” and these shall have rectangular symbols in accordance with IEC 117 15. 10 Action of binary signals on analogue signals When an input analogue signal A is influenced by a binary signal B, the output analogue signal Z can a) retain the last value;
47、or b) assume a predetermined minimum value; or c) assume a predetermined maximum value; or d) assume some other predetermined value. This may occur in both the 1-state and the 0-state of the binary signal. Diagrams are shown with electrical signals but are otherwise typical for all signals. Where “A
48、”, “Z”, etc., appear in the examples, they are not a part of the symbol. They are there for clarity of the symbol. 10.1 When B = 1, then Z = A. When B = 0, then there are four possibilities as follows: 10.1.1 Z retains the last momentary value (N) Licensed Copy: sheffieldun sheffieldun, na, Fri Nov
49、24 03:10:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1646-2:1983 8 BSI 01-1999 10.1.2 Z assumes the minimum value 10.1.3 Z assumes the maximum value 10.1.4 Z assumes a predetermined value, for example 70 % 10.2 When B = 0, then Z = A. When B = 1, then there are four possibilities, as follows: 10.2.1 Z retains the last momentary value N 10.2.2 Z assumes the minimum value 10.2.3 Z assumes the maximum value 10.2.4 Z assumes a predetermined value, for example 70 % Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 03:10:45 GMT+00
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