ISA S5.1 (1992) Instrumentation Symbols and Identification PDF

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COPYRIGHT NOTICE This material is electronically reproduced by ILI under license from the Instrument Society of America (ISA) who retain full copyright in the document. You have a nonexclusive, nontransferable license to use the document on one computer at any one time, and the document may not be reproduced, redistributed, or transmitted in any form except as may be permitted by Section 107 of Title 17 of the United States Code (related to fair use). ILI makes no guarantees or warranties as to the correctness of the document or as to the results arising from the purchase and use of the document and is not responsible for problems in the delivery of the document. Any difficulties or queries should be addressed to ILI below. In USA and Canada Contact:- ILI INFODISK INC, 610 Winters Avenue, Paramus, NJ 07652 Toll Free 1-888-454-2688 or 201-986-1131 Fax: 201-986-7886 E-mail: [email protected] Web: www.ili-info.com In Rest of World Contact:- ILI, Index House, Ascot, Berks, SL5 7EU, UK : +44 (0)1344 636400 Fax: +44 (0)1344 291194 E-mail: [email protected] Web: www.ili.co.uk  AMERICAN NATIONAL STANDARD ANSI/ISA–S5.1–1984 (R1992) Instrumentation Symbols and Identification Reaffirmed 13 July 1992 ANSI/ISA-S5.1 — Instrumentation Symbols and Identification ISBN 0-87664-844-8 Copyright  1984 by the Instrument Society of America. All rights reserved. Printed in the United States of America. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of the publisher. ISA 67 Alexander Drive P.O. Box 12277 Research Triangle Park, North Carolina 27709 Preface This preface is included for information and is not a part of ANSI/ISA-S5.1. This standard has been prepared as part of the service of ISA toward a goal of uniformity in the field of instrumentation. To be of real value, this document should not be static, but should be subject to periodic review. Toward this end, the Society welcomes all comments and criticisms, and asks that they be addressed to the Secretary, Standards and Practices Board, ISA, 67 Alexander Drive, P.O. Box 12277, Research Triangle Park, NC 27709, Telephone (919) 549- 8411, e-mail: [email protected]. The ISA Standards and Practices Department is aware of the growing need for attention to the metric system of units in general, and the International System of Units (SI) in particular, in the preparation of instrumentation standards. The Department is further aware of the benefits to U.S.A. users of ISA standards of incorporating suitable references to the SI (and the metric system) in their business and professional dealings with other countries. Toward this end, this Department will endeavor to introduce SI-acceptable metric units in all new and revised standards to the greatest extent possible. The Metric Practice Guide, which has been published by the Institute of Electrical and Electronics Engineers as ANSI/IEEE Std. 268-1982, and future revisions will be the reference guide for definitions, symbols, abbreviations, and conversion factors. It is the policy of ISA to encourage and welcome the participation of all concerned individuals and interests in the development of ISA standards. Participation in the ISA standards-making process by an individual in no way constitutes endorsement by the employer of that individual, of ISA, or of any of the standards that ISA develops. The information contained in the preface, footnotes, and appendices is included for information only and is not a part of the standard. The instrumentation symbolism and identification techniques described in the standard accommodate the advances in technology and reflect the collective industrial experience gained since the publication of Recommended Practice RP5.1 in 1949. This revision attempts to strengthen the standard in its role as a tool of communication in the process industries. Communication presupposes a common language; or, at the very least, it is facilitated by one. The standard offers the foundation for that common language. When integrated into a system, the symbols and designations presented here form a concise, dedicated language which communicates concepts, facts, intent, instructions, and knowledge about measurement and control systems in the process industries. This document is a consensus standard rather than a mandatory one. As such, it has many of the strengths and the weaknesses of consensus standards. Its primary strength is that it can be used in widespread, interdisciplinary ways. Its weakness is generally that of not being specific enough to satisfy the special requirements of particular interest groups. The symbols and identification contained in ISA-S5.1 have evolved by the consensus method and are intended for wide application throughout the process industries. The symbols and designations are used as conceptualizing aids, as design tools, as teaching devices, and as a concise and specific means of communication on all types and kinds of technical, engineering, procurement, construction, and maintenance documents. ANSI/ISA-S5.1-1984 (R 1992) 3 In the past, the standard has been flexible enough to serve all of the uses just described. In the future, it must continue to do so. To this end, this revision offers symbols, identification, and definitions for concepts that were not previously described; for example, shared display/control, distributed control, and programmable control. Definitions were broadened to accommodate the fact that, although similar functions are being performed by the new control systems, these functions are frequently not related to a uniquely identifiable instrument; yet they still must be conceptualized and identified. The excellent SAMA (Scientific Apparatus Makers Association) method of functional diagramming was used to describe function blocks and function designators. To help the batch processing industries, where binary (on-off) symbolism is extremely useful, new binary line symbols were introduced and first-letter Y was selected to represent an initiating variable which could be categorized as an event, presence, or state. In general, breadth of application as opposed to narrowness has been emphasized. The ISA Standards Committee on Instrumentation Symbols and Identification operates within the ISA Standards and Practices Department, with William Calder III as vice president. The persons listed below served as members of or advisors to the SP5.1 committee. The SP5.1 committee is deeply appreciative of the work of previous SP5.1 committees and has tried to treat their work with the respect it deserves. In addition, this committee would like to acknowledge the work of the SP5.3 committee in developing ISA-S5.3, "Graphic Symbols for Distributed Control/Shared Display Instrumentation, Logic and Computer Systems." The key elements of ISA-S5.3 have been incorporated into ISA-S5.1, and it is the Society's intent to withdraw ISA-S5.3 after publication of this revision of ISA-S5.1. The following people served as members of ISA Committee SP5.1, which prepared this standard: NAME COMPANY R. Mulley, Chairman Fluor Engineers, Inc. E. J. Blahut Blahut Engineering, Inc. P. R. Boubel TXE, Inc. J. P. Carew Stone and Webster Engineering Corporation N. Dogra ANK Engineers J. E. Doyle Tweedcrest Limited C. R. Gross EXXON Company U.S.A. T. E. Hamler Owens Corning Fiberglass Corporation F. Horn Allied Chemical Company A. A. Iverson ARCO Chemical Company A. Langelier Polaroid Corporation W. E. Mapes Eastman Kodak Company T. C. McAvinew Vertech Treatment Systems W. L. Mostia AMOCO Chemicals G. K. Pace Phelps Dodge Corporation G. Platt*, Past Chairman Bechtel Power Corporation A. W. Reeve AWR Controls (Canada) Ltd. S. Sankaran McDermott Engineering R. M. Shah Olin Chemicals Corporation D. G. Turnbull Sandwell and Company, Limited R. von Brecht The M. W. Kellogg Company G. Wilbanks The Rust Engineering Company *Member Emeritus 4 ANSI/ISA-S5.1-1984 (R 1992) The following people served as members of ISA Committee SP5: NAME COMPANY D. E. Rapley, Chairman Stearns Catalytic Corporation R. C. Greer Bailey Controls Company D. G. Kempfer Standard Oil Company of Ohio R. H. Kind El Paso Natural Gas Company R. Mulley Fluor Engineers, Inc. T. J. Myron The Foxboro Company This standard was approved for publication by the ISA Standards and Practices Board in September 1984. NAME COMPANY W. Calder III, Chairman The Foxboro Company P. V. Bhat Monsanto Company N. L. Conger Conoco B. Feikle Bailey Controls Company H. S. Hopkins Westinghouse Electric Company J. L. Howard Boeing Aerospace Company R. T. Jones Philadelphia Electric Company R. Keller The Boeing Company O. P. Lovett, Jr. ISIS Corporation E. C. Magison Honeywell, Inc. A. P. McCauley Chagrin Valley Controls, Inc. J. W. Mock Bechtel Corporation E. M. Nesvig ERDCO Engineering Corporation R. Prescott Moore Products Company D. E. Rapley Stearns Catalytic Corporation W. C. Weidman Gilbert Commonwealth, Inc. K. A. Whitman Consultant P. Bliss* Consultant B. A. Christensen* Contintental Oil Company L. N. Combs* Retired R. L. Galley* Consultant T. J. Harrison* IBM Corporation R. G. Marvin* Roy G. Marvin Company W. B. Miller* Moore Products Company G. Platt* Bechtel Power Corporation J. R. Williams* Stearns Catalytic Corporation *Director Emeritus ANSI/ISA-S5.1-1984 (R 1992) 5 Contents Section Title Section Number 1 Purpose........................................................................................................................ 9 2 Scope............................................................................................................................ 9 2.1 General.............................................................................................................. 9 2.2 Application to industries.................................................................................... 9 2.3 Application to work activities............................................................................. 9 2.4 Application to classes of instrumentation and to instrument functions............ 10 2.5 Extent of functional identification..................................................................... 10 2.6 Extent of loop identification............................................................................. 10 3 Definitions.................................................................................................................. 10 4 Outline of the identification system......................................................................... 13 4.1 General............................................................................................................ 13 4.2 Functional identification................................................................................... 14 4.3 Loop identification........................................................................................... 15 4.4 Symbols........................................................................................................... 16 5 Tables.......................................................................................................................... 17 6 Drawings.................................................................................................................... 27 6.1 Cautionary notes............................................................................................. 27 6.2 Instrument line symbols................................................................................... 28 6.3 General instrument or function symbols.......................................................... 29 6.4 Control valve body symbols, damper symbols................................................ 31 6.5 Actuator symbols............................................................................................. 32 6.6 Symbols for self-actuated regulators, valves, and other devices.................... 34 6.7 Symbols for actuator action in event of actuator power failure........................ 37 6.8 Primary element symbols................................................................................ 38 6.9 Examples — functions..................................................................................... 48 6.10 Examples — miscellaneous combinations...................................................... 56 6.11 Example — complex combinations................................................................. 61 6.12 Example — degree of detail............................................................................ 62 ANSI/ISA-S5.1-1984 (R 1992) 7 1 Purpose The purpose of this standard is to establish a uniform means of designating instruments and instrumentation systems used for measurement and control. To this end, a designation system that includes symbols and an identification code is presented. 2 Scope 2.1 General 2.1.1 The procedural needs of various users are different. The standard recognizes these needs, when they are consistent with the objectives of the standard, by providing alternative symbolism methods. A number of examples are provided for adding information or simplifying the symbolism, as desired. 2.1.2 Process equipment symbols are not part of this standard, but are included only to illustrate applications of instrumentation symbols. 2.2 Application to industries 2.2.1 The standard is suitable for use in the chemical, petroleum, power generation, air condition- ing, metal refining, and numerous other, process industries. 2.2.2 Certain fields, such as astronomy, navigation, and medicine, use very specialized instruments that are different from the conventional industrial process instruments. No specific effort was made to have the standard meet the requirements of those fields. However, it is expected that the standard will be flexible enough to meet many of the needs of special fields. 2.3 Application to work activities 2.3.1 The standard is suitable for use whenever any reference to an instrument or to a control system function is required for the purposes of symbolization and identification. Such references may be required for the following uses, as well as others: Design sketches Teaching examples Technical papers, literature, and discussions Instrumentation system diagrams, loop diagrams, logic diagrams Functional descriptions Flow diagrams: Process, Mechanical, Engineering, Systems, Piping (Process) and Instrumentation Construction drawings Specifications, purchase orders, manifests, and other lists ANSI/ISA-S5.1-1984 (R 1992) 9  Identification (tagging) of instruments and control functions Installation, operating and maintenance instructions, drawings, and records 2.3.2 The standard is intended to provide sufficient information to enable anyone reviewing any document depicting process measurement and control (who has a reasonable amount of process knowledge) to understand the means of measurement and control of the process. The detailed knowledge of a specialist in instrumentation is not a prerequisite to this understanding. 2.4 Application to classes of instrumentation and to instrument functions The symbolism and identification methods provided in this standard are applicable to all classes of process measurement and control instrumentation. They can be used not only to describe discrete instruments and their functions, but also to describe the analogous functions of systems which are variously termed "shared display," "shared control," "distributed control," and "computer control." 2.5 Extent of functional identification The standard provides for the identification and symbolization of the key functions of an instrument. Additional details of the instrument are better described in a suitable specification, data sheet, or other document intended for those requiring such details. 2.6 Extent of loop identification The standard covers the identification of an instrument and all other instruments or control functions associated with it in a loop. The user is free to apply additional identification — by serial number, unit number, area number, plant number, or by other means. 3 Definitions For the purpose of understanding this standard, the following definitions apply. For a more complete treatment, see ISA-S51.1 and the ISA-S75 series of standards. Terms italicized in a definition are also defined in this section. Accessible: A term applied to a device or function that can be used or be seen by an operator for the purpose of performing control actions, e.g., set point changes, auto-manual transfer, or on-off actions. Alarm: A device or function that signals the existence of an abnormal condition by means of an audible or visible discrete change, or both, intended to attract attention. It is not recommended that the term alarm switch or alarm be used to designate a device whose operation is simply to close or open a circuit that may or may not be used for normal or abnormal interlock, start-up, shutdown, actuation of a pilot light or an alarm device, or the like. The first device is properly designated as a level switch, a flow switch, etc., because "switching" is what the device does. The device may be designated as an alarm only if the device itself contains the alarm function. [See also Table 1, note (13).] Assignable: A term applied to a feature permitting the channeling (or directing) of a signal from one device to another without the need for switching, patching, or changes in wiring. Auto-manual station : Synonym for control station. 10 ANSI/ISA-S5.1-1984 (R 1992) Balloon: Synonym for bubble. Behind the panel: A term applied to a location that is within an area that contains (1) the instrument panel, (2) its associated rack-mounted hardware, or (3) is enclosed within the panel. Behind the panel devices are not accessible for the operator's normal use, and are not designated as local or front-of-panel-mounted. In a very broad sense, "behind the panel" is equivalent to "not normally accessible to the operator." Binary: A term applied to a signal or device that has only two discrete positions or states. When used in its simplest form, as in "binary signal" (as opposed to "analog signal"), the term denotes an "on-off" or "high-low" state, i.e., one which does not represent continuously varying quantities. Board: Synonym for panel. Bubble: The circular symbol used to denote and identify the purpose of an instrument or function. It may contain a tag number. Synonym for balloon. Computing device: A device or function that performs one or more calculations or logic operations, or both, and transmits one or more resultant output signals. A computing device is sometimes called a computing relay. Configurable: A term applied to a device or system whose functional characteristics can be selected or rearranged through programming or other methods. The concept excludes rewiring as a means of altering the configuration. Controller: A device having an output that varies to regulate a controlled variable in a specified manner. A controller may be a self-contained analog or digital instrument, or it may be the equivalent of such an instrument in a shared-control system. An automatic controller varies its output automatically in response to a direct or indirect input of a measured process variable. A manual controller is a manual loading station, and its output is not dependent on a measured process variable but can be varied only by manual adjustment. A controller may be integral with other functional elements of a control loop. Control station : A manual loading station that also provides switching between manual and automatic control modes of a control loop. It is also known as an auto-manual station. In addition, the operator interface of a distributed control system may be regarded as a control station. Control valve: A device, other than a common, hand-actuated ON-OFF valve or self-actuated check valve, that directly manipulates the flow of one or more fluid process streams. It is expected that use of the designation "hand control valve" will be limited to hand-actuated valves that (1) are used for process throttling, or (2) require identification as an instrument. Converter : A device that receives information in one form of an instrument signal and transmits an output signal in another form. An instrument which changes a sensor's output to a standard signal is properly designated as a transmitter, not a converter. Typically, a temperature element (TE) may connect to a transmitter (TT), not to a converter (TY). A converter is also referred to as a transducer ; however, "transducer" is a completely general term, and its use specifically for signal conversion is not recommended. Digital: A term applied to a signal or device that uses binary digits to represent continuous values or discrete states. Distributed control system: A system which, while being functionally integrated, consists of subsystems which may be physically separate and remotely located from one another. ANSI/ISA-S5.1-1984 (R 1992) 11 Final control element: The device that directly controls the value of the manipulated variable of a control loop. Often the final control element is a control valve. Function: The purpose of, or an action performed by, a device. Identification: The sequence of letters or digits, or both, used to designate an individual instrument or loop. Instrument: A device used directly or indirectly to measure and/or control a variable. The term includes primary elements, final control elements, computing devices, and electrical devices such as annunciators, switches, and pushbuttons. The term does not apply to parts (e.g., a receiver bellows or a resistor) that are internal components of an instrument. Instrumentation: A collection of instruments or their application for the purpose of observation, measurement, control, or any combination of these. Local: The location of an instrument that is neither in nor on a panel or console, nor is it mounted in a control room. Local instruments are commonly in the vicinity of a primary element or a final control element. The word "field" is often used synonymously with local. Local panel: A panel that is not a central or main panel. Local panels are commonly in the vicinity of plant subsystems or sub-areas. The term "local panel instrument" should not be confused with "local instrument." Loop: A combination of two or more instruments or control functions arranged so that signals pass from one to another for the purpose of measurement and/or control of a process variable. Manual loading station : A device or function having a manually adjustable output that is used to actuate one or more remote devices. The station does not provide switching between manual and automatic control modes of a control loop (see controller and control station). The station may have integral indicators, lights, or other features. It is also known as a manual station or a manual loader. Measurement: The determination of the existence or the magnitude of a variable. Monitor : A general term for an instrument or instrument system used to measure or sense the status or magnitude of one or more variables for the purpose of deriving useful information. The term monitor is very unspecific — sometimes meaning analyzer, indicator, or alarm. Monitor can also be used as a verb. Monitor light: Synonym for pilot light. Panel: A structure that has a group of instruments mounted on it, houses the operator-process interface, and is chosen to have a unique designation. The panel may consist of one or more sections, cubicles, consoles, or desks. Synonym for board. Panel-mounted: A term applied to an instrument that is mounted on a panel or console and is accessible for an operator's normal use. A function that is normally accessible to an operator in a shared-display system is the equivalent of a discrete panel-mounted device. Pilot light: A light that indicates which of a number of normal conditions of a system or device exists. It is unlike an alarm light, which indicates an abnormal condition. The pilot light is also known as a monitor light. Primary element: Synonym for sensor. Process: Any operation or sequence of operations involving a change of energy, state, composition, dimension, or other properties that may be defined with respect to a datum. Process variable: Any variable property of a process. The term process variable is used in this standard to apply to all variables other than instrument signals. 12 ANSI/ISA-S5.1-1984 (R 1992) Program: A repeatable sequence of actions that defines the status of outputs as a fixed relationship to a set of inputs. Programmable logic controller : A controller, usually with multiple inputs and outputs, that contains an alterable program. Relay: A device whose function is to pass on information in an unchanged form or in some modified form. Relay is often used to mean computing device. The latter term is preferred. The term "relay" also is applied specifically to an electric, pneumatic, or hydraulic switch that is actuated by a signal. The term also is applied to functions performed by a relay. Scan: To sample, in a predetermined manner, each of a number of variables intermittently. The function of a scanning device is often to ascertain the state or value of a variable. The device may be associated with other functions such as recording and alarming. Sensor: That part of a loop or instrument that first senses the value of a process variable, and that assumes a corresponding, predetermined, and intelligible state or output. The sensor may be separate from or integral with another functional element of a loop. The sensor is also known as a detector or primary element. Set point: An input variable that sets the desired value of the controlled variable. The set point may be manually set, automatically set, or programmed. Its value is expressed in the same units as the controlled variable. Shared controller: A controller, containing preprogrammed algorithms that are usually accessible, configurable, and assignable. It permits a number of process variables to be controlled by a single device. Shared display: The operator interface device (usually a video screen) used to display process control information from a number of sources at the command of the operator. Switch: A device that connects, disconnects, selects, or transfers one or more circuits and is not designated as a controller, a relay, or a control valve. As a verb, the term is also applied to the functions performed by switches. Test point: A process connection to which no instrument is permanently connected, but which is intended for the temporary or intermittent connection of an instrument. Transducer: A general term for a device that receives information in the form of one or more physical quantities, modifies the information and/or its form, if required, and produces a resultant output signal. Depending on the application, the transducer can be a primary element, transmitter, relay, converter or other device. Because the term "transducer" is not specific, its use for specific applications is not recommended. Transmitter: A device that senses a process variable through the medium of a sensor and has an output whose steady-state value varies only as a predetermined function of the process variable. The sensor may or may not be integral with the transmitter. 4 Outline of the identification system 4.1 General 4.1.1 Each instrument or function to be identified is designated by an alphanumeric code or tag number as shown in Figure 1. The loop identification part of the tag number generally is common ANSI/ISA-S5.1-1984 (R 1992) 13 to all instruments or functions of the loop. A suffix or prefix may be added to complete the identi- fication. Typical identification is shown in Figure 1. TYPICAL TAG NUMBER TIC 103 - Instrument Identification or Tag Number T 103 - Loop Identification 103 - Loop Number TIC - Functional Identification T - First-letter IC - Succeeding-Letters EXPANDED TAG NUMBER 10-PAH-5A - Tag Number 10 - Optional Prefix A - Optional Suffix Note: Hyphens are optional as separators Figure 1 — Tag numbers 4.1.2 The instrument loop number may include coded information, such as plant area designation. It is also possible to set aside specific series of numbers to designate special functions; for instance, the series 900 to 999 could be used for loops whose primary function is safety-related. 4.1.3 Each instrument may be represented on diagrams by a symbol. The symbol may be ac- companied by a tag number. 4.2 Functional identification 4.2.1 The functional identification of an instrument or its functional equivalent consists of letters from Table 1 and includes one first-letter (designating the measured or initiating variable) and one or more succeeding-letters (identifying the functions performed). 4.2.2 The functional identification of an instrument is made according to the function and not according to the construction. Thus, a differential-pressure recorder used for flow measurement is identified by FR; a pressure indicator and a pressure-actuated switch connected to the output of a pneumatic level transmitter are identified by LI and LS, respectively. 4.2.3 In an instrument loop, the first-letter of the functional identification is selected according to the measured or initiating variable, and not according to the manipulated variable. Thus, a control valve varying flow according to the dictates of a level controller is an LV, not an FV. 4.2.4 The succeeding-letters of the functional identification designate one or more readout or passive functions and/or output functions. A modifying-letter may be used, if required, in addition to one or more other succeeding-letters. Modifying-letters may modify either a first-letter or suc- ceeding-letters, as applicable. Thus, TDAL contains two modifiers. The letter D changes the measured variable T into a new variable, "differential temperature." The letter L restricts the readout function A, alarm, to represent a low alarm only. 4.2.5 The sequence of identification letters begins with a first-letter selected according to Table 1. Readout or passive functional letters follow in any order, and output functional letters follow these in any sequence, except that output letter C (control) precedes output letter V (valve), e.g., PCV, a self-actuated control valve. However, modifying-letters, if used, are interposed so that they are placed immediately following the letters they modify. 14 ANSI/ISA-S5.1-1984 (R 1992) 4.2.6 A multiple function device may be symbolized on a diagram by as many bubbles as there are measured variables, outputs, and/or functions. Thus, a temperature controller with a switch may be identified by two tangent bubbles — one inscribed TIC-3 and one inscribed TSH-3. The instrument would be designated TIC/TSH-3 for all uses in writing or reference. If desired, however, the abbreviation TIC-3 may serve for general identification or for purchasing, while TSH-3 may be used for electric circuit diagrams. 4.2.7 The number of functional letters grouped for one instrument should be kept to a minimum according to the judgment of the user. The total number of letters within one group should not exceed four. The number within a group may be kept to a minimum by: 1) Arranging the functional letters into subgroups. This practice is described in Section 4.2.6 for instruments having more than one measured variable or input, but it may also be used for other instruments. 2) Omitting the I (indicate) if an instrument both indicates and records the same measured variable. 4.2.8 All letters of the functional identification are uppercase. 4.3 Loop identification 4.3.1 The loop identification consists of a first-letter and a number. Each instrument within a loop has assigned to it the same loop number and, in the case of parallel numbering, the same first- letter. Each instrument loop has a unique loop identification. An instrument common to two or more loops should carry the identification of the loop which is considered predominant. 4.3.2 Loop numbering may be parallel or serial. Parallel numbering involves starting a numerical sequence for each new first-letter, e.g., TIC-100, FRC-100, LIC-100, AI-100, etc. Serial numbering involves using a single sequence of numbers for a project or for large sections of a project, regard- less of the first-letter of the loop identification, e.g., TIC-100, FRC-101, LIC-102, Al-103, etc. A loop numbering sequence may begin with 1 or any other convenient number, such as 001, 301 or 1201. The number may incorporate coded information; however, simplicity is recommended. 4.3.3 If a given loop has more than one instrument with the same functional identification, a suffix may be appended to the loop number, e.g., FV-2A, FV-2B, FV-2C, etc., or TE-25-1, TE-25-2, etc. However, it may be more convenient or logical in a given instance to designate a pair of flow transmitters, for example, as FT-2 and FT-3 instead of FT-2A and FT-2B. The suffixes may be applied according to the following guidelines: 1) An uppercase suffix letter should be used, i.e., A, B, C, etc. 2) For an instrument such as a multipoint temperature recorder that prints numbers for point identification, the primary elements may be numbered TE-25-1, TE-25-2, TE- 25-3, etc., corresponding to the point identification number. 3) Further subdivisions of a loop may be designated by serially alternating suffix letters and numbers. (See Section 6.9R(3).) 4.3.4 An instrument that performs two or more functions may be designated by all of its functions. For example, a flow recorder FR-2 with a pressure pen PR-4 may be designated FR-2/PR-4. A two-pen pressure recorder may be PR-7/8, and a common annunciator window for high and low temperature alarms may be TAHL-21. Note that the slash is not necessary when distinctly separate devices are not present. 4.3.5 Instrument accessories such as purge meters, air sets, and seal pots that are not explicitly shown on a diagram but that need a designation for other purposes should be tagged individually ANSI/ISA-S5.1-1984 (R 1992) 15 according to their functions and should use the same loop identification as the instrument they directly serve. Application of such a designation does not imply that the accessory must be shown on the diagram. Alternatively, the accessories may use the identical tag number as that of their associated instrument, but with clarifying words added. Thus an orifice flange union associated with orifice plate FE-7 should be tagged FX-7, but may be designated FE-7 FLANGES. A purge meter associated with pressure gauge PI-8 may be tagged PI-8 PURGE. A thermowell used with thermometer TI-9 should be tagged TW-9, but may be tagged TI-9 THERMOWELL. The rules for loop identification need not be applied to instruments and accessories that are purchased in bulk quantities if it is the user's practice to identify these items by other means. 4.4 Symbols 4.4.1 The examples in this standard illustrate the symbols that are intended to depict instrumen- tation on diagrams and drawings. Methods of symbolization and identification are demonstrated. The examples show identification that is typical for the pictured instrument or functional interrela- tionships. The symbols indicating the various instruments or functions have been applied in typical ways in the illustrations. This usage does not imply, however, that the applications or designations of the instruments or functions are restricted in any way. No inference should be drawn that the choice of any of the schemes for illustration constitutes a recommendation for the illustrated meth- ods of measurement or control. Where alternative symbols are shown without a statement of preference, the relative sequence of symbols does not imply a preference. 4.4.2 The bubble may be used to tag distinctive symbols, such as those for control valves, when such tagging is desired. In such instances, the line connecting the bubble to the instrument symbol is drawn close to, but not touching, the symbol. In other instances, the bubble serves to represent the instrument proper. 4.4.3 A distinctive symbol whose relationship to the remainder of the loop is easily apparent from a diagram need not be individually tagged on the diagram. For example, an orifice flange or a control valve that is part of a larger system need not be shown with a tag number on a diagram. Also, where there is a primary element connected to another instrument on a diagram, use of a symbol to represent the primary element on the diagram is optional. 4.4.4 A brief explanatory notation may be added adjacent to a symbol or line to clarify the function of an item. For instance, the notations 3-9 psig and 9-15 psig adjacent to the signal lines to two valves operating in split range, taken together with the symbols for the failure modes, allow complete understanding of the intent. Similarly, when two valves are operated in a diverting or mixing mode from a common signal, the notations 3-15 psig and 15-3 psig, together with the failure modes, allow understanding of the function. 4.4.5 The sizes of the tagging bubbles and the miscellaneous symbols shown in the examples are the sizes generally recommended; however, the optimum sizes may vary depending on whether or not the finished diagram is to be reduced in size and depending on the number of characters that are expected in the instrument tagging designation. The sizes of the other symbols may be selected as appropriate to accompany the symbols of other equipment on a diagram. 4.4.6 Aside from the general drafting requirements for neatness and legibility, symbols may be drawn with any orientation. Likewise, signal lines may be drawn on a diagram entering or leaving the appropriate part of a symbol at any angle. However, the function block designators of Table 3 and the tag numbers should always be drawn with a horizontal orientation. Directional arrowheads should be added to signal lines when needed to clarify the direction of flow of information. The judicious use of such arrowheads, especially on complex drawings, will often facilitate understand- ing of the system. 16 ANSI/ISA-S5.1-1984 (R 1992) 4.4.7 The electrical, pneumatic, or other power supply to an instrument is not expected to be shown unless it is essential to an understanding of the operation of the instrument or the loop. 4.4.8 In general, one signal line will suffice to represent the interconnections between two instru- ments on flow diagrams even though they may be connected physically by more than one line. 4.4.9 The sequence in which the instruments or functions of a loop are connected on a diagram should reflect the functional logic or information flow, although this arrangement will not necessarily correspond to the signal connection sequence. Thus, an electronic loop using analog voltage signals requires parallel wiring, while a loop using analog current signals requires series intercon- nections. However, the diagram in both instances should be drawn as though all the wiring were parallel, to show the functional interrelationships clearly while keeping the presentation indepen- dent of the type of instrumentation finally installed. The correct interconnections are expected to be shown on a suitable diagram. 4.4.10 The degree of detail to be applied to each document or sketch is entirely at the discretion of the user of the standard. The symbols and designations in this standard can depict both hardware and function. Sketches and technical papers will usually contain highly simplified symbolism and identification. Process flow diagrams will usually be less detailed than engineering flow diagrams. Engineering flow diagrams may show all in-line components, but may differ from user to user in the amount of off-line detail shown. In any case, consistency should be established for each application. The terms simplified, conceptual, and detailed as applied to the diagrams of 6.12 were chosen to represent a cross section of typical usage. Each user must establish the degree of detail that fulfills the purposes of the specific document or sketch being generated. 4.4.11 It is common practice for engineering flow diagrams to omit the symbols of interlock- hardware components that are actually necessary for a working system, particularly when sym- bolizing electric interlock systems. For example, a level switch may be shown as tripping a pump, or separate flow and pressure switches may be shown as actuating a solenoid valve or other interlock devices. In both instances, auxiliary electrical relays and other components may be considered details to be shown elsewhere. By the same token, a current transformer sometimes will be omitted and its receiver shown connected directly to the process — in this case the electric motor. 4.4.12 Because the distinctions between shared display/shared control and computer functions are sometimes blurred, in choosing symbols to represent them the user must rely on manufacturers' definitions, usage in a particular industry, and personal judgment. 5 Tables The purpose of Section 5, Tables, is to define certain of the building blocks of the identification and symbolic representation system used in this standard in a concise, easily-referenced manner. Table 1, Identification Letters, together with the Notes for Table 1, define and explain the individual letter designators used as functional identifiers in accordance with the rules of Section 4.2, Functional Identification. Table 2, Typical Letter Combinations, attempts to facilitate the task of choosing acceptable combinations of identifying letters. ANSI/ISA-S5.1-1984 (R 1992) 17 Table 3, Function Blocks - Function Designations, is an adaptation of the SAMA (Scientific Apparatus Manufacturers Association) method of functional diagramming. Two basic uses are found for these symbols: as stand-alone function blocks on conceptual diagrams, or as flags which designate functions performed by bubbles on more detailed drawings. A third use is a combination of the first two and is found in shared control systems where, for instance, the measured variable signal line enters a square root function block that is drawn adjacent to a shared controller. Two omissions will be noted: The SAMA symbol for Transfer and that for an Analog Signal Generator. Since the ultimate use of ISA-S5.1 symbolism usually requires identification to be associated with a symbol, it is advisable to use the HIC (manual loader) bubble for an analog signal generator and an HS (hand switch) with or without a relay bubble for a transfer function. 5.1 Notes for Table 1 1) A "user's choice" letter is intended to cover unlisted meanings that will be used repetitively in a particular project. If used, the letter may have one meaning as a first- letter and another meaning as a succeeding-letter. The meanings need to be defined only once in a legend, or other place, for that project. For example, the letter N may be defined as "modulus of elasticity" as a first-letter and "oscilloscope" as a succeeding-letter. 2) The unclassified letter X is intended to cover unlisted meanings that will be used only once or used to a limited extent. If used, the letter may have any number of meanings as a first-letter and any number of meanings as a succeeding-letter. Except for its use with distinctive symbols, it is expected that the meanings will be defined outside a tagging bubble on a flow diagram. For example, XR-2 may be a stress recorder and XX-4 may be a stress oscilloscope. 3) The grammatical form of the succeeding-letter meanings may be modified as required. For example, "indicate" may be applied as "indicator" or "indicating," "transmit" as "transmitter" or "transmitting," etc. 4) Any first-letter, if used in combination with modifying letters D (differential), F (ratio), M (momentary), K (time rate of change), Q (integrate or totalize), or any combination of these is intended to represent a new and separate measured variable, and the combination is treated as a first-letter entity. Thus, instruments TDI and TI indicate two different variables, namely, differential-temperature and temperature. Modifying letters are used when applicable. 5) First-letter A (analysis) covers all analyses not described by a "user's choice" letter. It is expected that the type of analysis will be defined outside a tagging bubble. 6) Use of first-letter U for "multivariable" in lieu of a combination of first-letters is optional. It is recommended that nonspecific variable designators such as U be used sparingly. 7) The use of modifying terms "high," "low," "middle" or "intermediate," and "scan" is optional. 8) The term "safety" applies to emergency protective primary elements and emergency protective final control elements only. Thus, a self-actuated valve that prevents operation of a fluid system at a higher-than-desired pressure by bleeding fluid from the system is a back-pressure-type PCV, even if the valve is not intended to be used normally. However, this valve is designated as a PSV if it is intended to protect against emergency conditions, i.e., conditions that are hazardous to personnel and/or equipment and that are not expected to arise normally. 18 ANSI/ISA-S5.1-1984 (R 1992)  The designation PSV applies to all valves intended to protect against emergency pressure conditions regardless of whether the valve construction and mode of op- eration place them in the category of the safety valve, relief valve, or safety relief valve. A rupture disc is designated PSE. 9) The passive function G applies to instruments or devices that provide an uncalibrated view, such as sight glasses and television monitors. 10) "Indicate" normally applies to the readout—analog or digital—of an actual measurement. In the case of a manual loader, it may be used for the dial or setting indication, i.e., for the value of the initiating variable. 11) A pilot light that is part of an instrument loop should be designated by a first-letter followed by the succeeding-letter L. For example, a pilot light that indicates an expired time period should be tagged KQL. If it is desired to tag a pilot light that is not part of an instrument loop, the light is designated in the same way. For example, a running light for an electric motor may be tagged EL, assuming voltage to be the appropriate measured variable, or YL, assuming the operating status is being monitored. The unclassified variable X should be used only for applications which are limited in extent. The designation XL should not be used for motor running lights, as these are commonly numerous. It is permissible to use the user's choice letters M, N or O for a motor running light when the meaning is previously defined. If M is used, it must be clear that the letter does not stand for the word "motor," but for a monitored state. 12) Use of a succeeding-letter U for "multifunction" instead of a combination of other functional letters is optional. This nonspecific function designator should be used sparingly. 13) A device that connects, disconnects, or transfers one or more circuits may be either a switch, a relay, an ON-OFF controller, or a control valve, depending on the application. If the device manipulates a fluid process stream and is not a hand-actuated ON-OFF block valve, it is designated as a control valve. It is incorrect to use the succeeding-letters CV for anything other than a self-actuated control valve. For all applications other than fluid process streams, the device is designated as follows: A switch, if it is actuated by hand. A switch or an ON-OFF controller, if it is automatic and is the first such device in a loop. The term "switch" is generally used if the device is used for alarm, pilot light, selection, interlock, or safety. The term "controller" is generally used if the device is used for normal operating control. A relay, if it is automatic and is not the first such device in a loop, i.e., it is actuated by a switch or an ON-OFF controller. 14) It is expected that the functions associated with the use of succeeding-letter Y will be defined outside a bubble on a diagram when further definition is considered necessary. This definition need not be made when the function is self-evident, as for a solenoid valve in a fluid signal line. 15) The modifying terms "high," and "low," and "middle" or "intermediate" correspond to values of the measured variable, not to values of the signal, unless otherwise noted. For example, a high-level alarm derived from a reverse-acting level transmitter signal should be an LAH, even though the alarm is actuated when the signal falls to a low value. The terms may be used in combinations as appropriate. (See Section 6.9A.) ANSI/ISA-S5.1-1984 (R 1992) 19  16) The terms "high" and "low," when applied to positions of valves and other open-close devices, are defined as follows: "high" denotes that the valve is in or approaching the fully open position, and "low" denotes that it is in or approaching the fully closed position. 17) The word "record" applies to any form of permanent storage of information that permits retrieval by any means. 18) For use of the term "transmitter" versus "converter," see the definitions in Section 3. 19) First-letter V, "vibration or mechanical analysis," is intended to perform the duties in machinery monitoring that the letter A performs in more general analyses. Except for vibration, it is expected that the variable of interest will be defined outside the tagging bubble. 20) First-letter Y is intended for use when control or monitoring responses are event- driven as opposed to time- or time schedule-driven. The letter Y, in this position, can also signify presence or state. 21) Modifying-letter K, in combination with a first-letter such as L, T, or W, signifies a time rate of change of the measured or initiating variable. The variable WKIC, for instance, may represent a rate-of-weight-loss controller. 22) Succeeding-letter K is a user's option for designating a control station, while the succeeding-letter C is used for describing automatic or manual controllers. (See Section 3, Definitions.) 20 ANSI/ISA-S5.1-1984 (R 1992)  Table 1 — Identification Letters FIRST-LETTER (4) SUCCEEDING-LETTERS (3) MEASURED OR READOUT OR INITIATING PASSIVE VARIABLE MODIFIER FUNCTION OUTPUT FUNCTION MODIFIER A Analysis (5,19) Alarm B Burner, Combustion User's Choice (1) User's Choice (1) User's Choice (1) C User's Choice (1) Control (13) D User's Choice (1) Differential (4) E Voltage Sensor (Primary Element) F Flow Rate Ratio (Fraction) (4) G User's Choice (1) Glass, Viewing Device (9) H Hand High (7, 15, 16) I Current (Electrical) Indicate (10) J Power Scan (7) K Time, Time Schedule Time Rate of Change Control Station (22) (4, 21) L Level Light (11) Low (7, 15, 16) M User's Choice (1) Momentary (4) Middle, Intermediate (7,15) N User's Choice (1) User's Choice (1) User's Choice (1) User's Choice (1) O User's Choice (1) Orifice, Restriction P Pressure, Vacuum Point (Test) Connection Q Quantity Integrate, Totalize (4) R Radiation Record (17) S Speed, Frequency Safety (8) Switch (13) T Temperature Transmit (18) U Multivariable (6) Multifunction (12) Multifunction (12) Multifunction (12) V Vibration, Mechanical Valve, Damper, Analysis (19) Louver (13) W Weight, Force Well X Unclassified (2) X Axis Unclassified (2) Unclassified (2) Unclassified (2) Y Event, State or Y Axis Relay, Compute, Presence (20) Convert (13, 14, 18) Z Position, Dimension Z Axis Driver, Actuator, Unclassified Final Control Element NOTE: Numbers in parentheses refer to specific explanatory notes in Section 5.1. ANSI/ISA-S5.1-1984 (R 1992) 21  5.3 Table 2 — Typical Letter Combinations 22 Switches and Controllers Readout Devices Alarm Devices* Transmitters Self- Solenoids, Initiating Actuated Relays, Well Viewing First- or Control Computing Primary Test or Device, Safety Final Letters Measured Vaiable Recording Indicating Blind Valves Recording Indicating High** Low Comb Recording Indicating Blind Devices Element Point Probe Glass Device Element A Analysis ARC AIC AC AR AI ASH ASL ASHL ART AIT AT AY AE AP AW AV B Burner/Combustion BRC BIC BC BR BI BSH BSL BSHL BRT BIT BT BY BE BW BG BZ C User’s Choice D User’s Choice E Voltage ERC EIC EC ER EI ESH ESL ESHL ERT EIT ET EY EE EZ F Flow Rate FRC FIC FC FCV, FR FI FSH FSL FSHL FRT FIT FT FY FE FP FG FV FICV FQ Flow Quantity FQRC FQIC FQR FQI FQSH FQSL FQIT FQT FQY FQE FQV FF Flow Ratio FFRC FFIC FFC FFR FFI FFSH FFSL FE FFV G User’s Choice H Hand HIC HC HS HV I Current IRC IIC IR II ISH ISL ISHL IRT IIT IT IY IE IZ J Power JRC JIC JR JI JSH JSL JSHL JRT JIT JT JY JE JV K Time KRC KIC KC KCV KR KI KSH KSL KSHL KRT KIT KT KY KE KV L Level LRC LIC LC LCV LR LI LSH LSL LSHL LRT LIT LT LY LE LW LG LV M User’s Choice N User’s Choice O User’s Choice P Pressure/ PRC PIC PC PCV PR PI PSH PSL PSHL PRT PIT PT PY PE PP PSV, PV Vacuum PSE PD Pressure, PDRC PDIC PDC PDCV PDR PDI PDSH PDSL PDRT PDIT PDT PDY PE PP PDV Differential Q Quantity QRC QIC QR QI QSH QSL QSHL QRT QIT QT QY QE QZ R Radiation RRC RIC RC RR RI RSH RSL RSHL RRT RIT RT RY RE RW RZ S Speed/Frequency SRC SIC SC SCV SR SI SSH SSL SSHL SRT SIT ST SY SE SV T Temperature TRC TIC TC TCV TR TI TSH TSL TSHL TRT TIT TT TY TE TP TW TSE TV TD Temperature, TDRC TDIC TDC TDCV TDR TDI TDSH TDSL TDRT TDIT TDT TDY TE TP TW TDV Differential ANSI/ISA-S5.1-1984 (R 1992) U Multivariable UR UI UY UV V Vibration/Machinery VR VI VSH VSL VSHL VRT VIT VT VY VE VZ Analysis W Weight/Force WRC WIC WC WCV WR WI WSH WSL WSHL WRT WIT WT WY WE WZ WD Weight/Force, WDRC WDIC WDC WDCV WDR WDI WDSH WDSL WDRT WDIT WDT WDY WE WDZ Differential X Unclassified Y Event/State/Presence YIC YC YR YI YSH YSL YT YY YE YZ Z Position/Dimension ZRC ZIC ZC ZCV ZR ZI ZSH ZSL ZSHL ZRT ZIT ZT ZY ZE ZV ZD Gauging/Deviation ZDRC ZDIC ZDC ZDCV ZDR ZDI ZDSH ZDSL ZDRT ZDIT ZDT ZDY ZDE ZDV Note: This table is not all-inclusive. Other Possible Combinations: *A, alarm, the annunciating device, may be used in the same FO (Restriction Orifice) PFR (Ratio) fashion as S, switch, the actuating device. FRK, HIK (Control Stations) KQI (Running Time Indicator) FX (Accessories) QQI (Indicating Counter) **The letters H and L may be omitted in the undefined case. TJR (Scanning Recorder) WKIC (Rate-of-Weight-Loss Controller) LLH (Pilot Light) HMS (Hand Momentary Switch)  5.4 Table 3 — Function Blocks - Function Designations ANSI/ISA-S5.1-1984 (R 1992) THE FUNCTION DESIGNATIONS ASSOCIATED WITH CONTROLLERS, COMPUTING DEVICES, CONVERTERS AND RELAYS MAY BE USED INDIVIDUALLY OR IN COMBINATION (ALSO, SEE TABLE 1, NOTE 14.). THE USE OF A BOX AVOIDS CONFUSION BY SETTING OFF THE SYMBOL FROM OTHER MARKINGS ON A DIAGRAM AND PERMITS THE FUNCTION TO BE USED AS A STAND-ALONE BLOCK ON CONCEPTUAL DESIGNS. 6 23 5.4 Table 3 — Continued 24 ANSI/ISA-S5.1-1984 (R 1992) 5.4 Table 3 — Continued ANSI/ISA-S5.1-1984 (R 1992) 25 5.4 Table 3 — Continued 26 ANSI/ISA-S5.1-1984 (R 1992) 6 Drawings 6.1 Cautionary notes 1) If a given drawing, or set of drawings, uses graphic symbols that are similar or identical in shape or configuration and that have different meanings because they are taken from different standards, then adequate steps must be taken to avoid misinterpretation of the symbols used. These steps may be to use caution notes, reference notes, comparison charts that illustrate and define the conflicting symbols, or other suitable means. This requirement is especially critical in cases where symbols taken from different disciplines are intermixed and their misinterpretation might cause danger to personnel or damage to equipment. 2) The titles Simplified Diagrams, Conceptual Diagrams and Detailed Diagrams of Section 6.12 were chosen to represent a cross section of symbol usage, not any particular generic document. (See 4.4.10 for a more complete discussion.) 3) The line symbols of Section 6.2 offer "user's choice" alternative electrical symbols and optional binary symbols. The subsequent examples use one consistent set of these alternatives and apply the binary options. This was done for consistency of appearance of the standard. It is recommended that the user choose either the dashed line electrical symbol or the triple cross hatch symbol and apply it consistently. The optional binary (on-off) symbols are available for those applications where the user finds it necessary to distinguish between analog and binary signals. If, in the user's judgment, the ap- plication does not require such differentiation, the reverse slash may be omitted from on-off signal line symbols. Consistency is recommended on a given set of documents. ANSI/ISA-S5.1-1984 (R 1992) 27 6.2 Instrument line symbols ALL LINES TO BE FINE IN RELATION TO PROCESS PIPING LINES. 28 ANSI/ISA-S5.1-1984 (R 1992) 6.3 General instrument or function symbols ANSI/ISA-S5.1-1984 (R 1992) 29 6.3 General instrument or function symbols (contd.) 30 ANSI/ISA-S5.1-1984 (R 1992) 6.4 Control valve body symbols, damper symbols ANSI/ISA-S5.1-1984 (R 1992) 31 6.5 Actuator symbols 32 ANSI/ISA-S5.1-1984 (R 1992) 6.5 Actuator symbols (contd.) ANSI/ISA-S5.1-1984 (R 1992) 33 6.6 Symbols for self-actuated regulators, valves, and other devices 34 ANSI/ISA-S5.1-1984 (R 1992) 6.6 Symbols for self-actuated regulators, valves, and other devices (contd.) ANSI/ISA-S5.1-1984 (R 1992) 35 6.6 Symbols for self-actuated regulators, valves, and other devices (contd.) 36 ANSI/ISA-S5.1-1984 (R 1992) 6.7 Symbols for actuator action in event of actuator power failure (shown typically for diaphragm-actuated control valve). ANSI/ISA-S5.1-1984 (R 1992) 37 6.8 Primary element symbols 38 ANSI/ISA-S5.1-1984 (R 1992) 6.8 Primary element symbols (contd.) ANSI/ISA-S5.1-1984 (R 1992) 39 6.8 Primary element symbols (contd.) 40 ANSI/ISA-S5.1-1984 (R 1992) 6.8 Primary element symbols (contd.) ANSI/ISA-S5.1-1984 (R 1992) 41 6.8 Primary element symbols (contd.) 42 ANSI/ISA-S5.1-1984 (R 1992) 6.8 Primary element symbols (contd.) ANSI/ISA-S5.1-1984 (R 1992) 43 6.8 Primary element symbols (contd.) 44 ANSI/ISA-S5.1-1984 (R 1992) 6.8 Primary element symbols (contd.) ANSI/ISA-S5.1-1984 (R 1992) 45 6.8 Primary element symbols (contd.) 46 ANSI/ISA-S5.1-1984 (R 1992) 6.8 Primary element symbols (contd.) ANSI/ISA-S5.1-1984 (R 1992) 47 6.9 Examples — functions 48 ANSI/ISA-S5.1-1984 (R 1992) 6.9 Examples — functions (contd.) ANSI/ISA-S5.1-1984 (R 1992) 49 6.9 Examples — functions (contd.) 50 ANSI/ISA-S5.1-1984 (R 1992) 6.9 Examples — functions (contd.) ANSI/ISA-S5.1-1984 (R 1992) 51 6.9 Examples — functions (contd.) 52 ANSI/ISA-S5.1-1984 (R 1992) 6.9 Examples — functions (contd.) ANSI/ISA-S5.1-1984 (R 1992) 53 6.9 Examples — functions (contd.) 54 ANSI/ISA-S5.1-1984 (R 1992) 6.9 Examples — functions (contd.) ANSI/ISA-S5.1-1984 (R 1992) 55 6.10 Examples — miscellaneous combinations 56 ANSI/ISA-S5.1-1984 (R 1992) 6.10 Examples — miscellaneous combinations (contd.) ANSI/ISA-S5.1-1984 (R 1992) 57 6.10 Examples — miscellaneous combinations (contd.) 58 ANSI/ISA-S5.1-1984 (R 1992) 6.10 Examples — miscellaneous combinations (contd.) ANSI/ISA-S5.1-1984 (R 1992) 59 6.10 Examples — miscellaneous combinations (contd.) 60 ANSI/ISA-S5.1-1984 (R 1992) 6.11 Example — complex combinations ANSI/ISA-S5.1-1984 (R 1992) 61 6.12 Example — degree of detail* 62 ANSI/ISA-S5.1-1984 (R 1992) 6.12 Example — degree of detail (contd.)* ANSI/ISA-S5.1-1984 (R 1992) 63 6.12 Example — degree of detail (contd.)* 64 ANSI/ISA-S5.1-1984 (R 1992) Index Term Para. No. Term Para. No. -A- Binary Accessible definition............................... 3 definition.............................. 3 graphic symbol.....................6.2 graphic symbols................... 6.3 Board (Panel) Actuator definition............................... 3 actuator action...................... 6.7 identification.........................6.3 graphic symbols................... 6.5 Burner, Combustion identification......................... 5.1 example................................6.8 Air Supply identification.........................5.1 identification......................... 6.2 -C- Alarm Complex Combinations definition............................... 3 example................................6.11 examples.............................. 6.9 Computer Function identification......................... 5.1 graphic symbol.....................6.3 Analysis Computing Device examples.............................. 6.8 definition............................... 3 identification......................... 5.1 example................................6.9 Assignable function................................. 5.4 definition............................... 3 identification.........................5.1 Auto-Manual Station Conceptual Diagrams (Control Station) example................................6.12 definition............................... 3 Conductivity (see Analysis) identification......................... 5.1 example................................6.8 Auxiliary Location Configurable graphic symbol..................... 6.3 definition............................... 3 Averaging Controller graphic symbol..................... 5.4 definition............................... 3 -B- Control Balloon, Bubble example................................6.9 definition............................... 3 identification.........................5.1 graphic symbol..................... 6.3 Control Station Behind-the-Panel (Auto-Manual Station) definition............................... 3 definition............................... 3 graphic symbol..................... 6.3 example................................6.9 Bias identification.........................5.1 graphic symbol..................... 5.4 Control Valve definition............................... 3 ANSI/ISA-S5.1-1984 (R 1992) 65 Term Para. No. Term Para. No. graphic symbols................... 6.4 graphic symbol.....................6.2 identification......................... 5.1 Electric Signal self-actuated......................... 6.6 graphic symbols................... 6.2 Converter Electric Supply definition............................... 3 identification.........................6.2 graphic symbols................... 5.4 Electrohydraulic Current (Electrical) graphic symbol.....................6.5 graphic symbols................... 6.8 Electromagnetic Signal identification......................... 5.1 graphic symbols................... 6.2 -D- Event Damper identification.........................5.1 graphic symbol..................... 6.4 Exponential Data Link graphic symbol.....................5.4 graphic symbol..................... 6.2 -F- Density Field Mounted (Local) example................................ 6.8 graphic symbol.....................6.3 Derivative Final Control Element graphic symbol..................... 5.4 definition............................... 3 Detailed Diagrams identification.........................5.1 example................................ 6.12 Flow Rate Diaphragm Seal graphic symbols................... 6.8 graphic symbol..................... 6.3 identification.........................5.1 Difference Force graphic symbol..................... 5.4 example................................6.8 Differential identification.........................5.1 examples.............................. 6.6, 6.9 Frequency identification......................... 5.1 identification.........................5.1 Digital Function definition............................... 3 definition............................... 3 graphic symbol..................... 6.5 examples.............................. 6.9 Dimension graphic symbols................... 6.3 identification......................... 5.1 identification.........................5.1, 5.4 Discrete Instruments Function Blocks graphic symbol..................... 6.3 identification.........................5.4 Distributed Control System Fusible Plug definition............................... 3 example................................6.6 Dividing -G- graphic symbol..................... 5.4 Gas Supply Driver identification.........................6.2 example................................ 6.9 Glass (Viewing Device) identification......................... 5.1 example................................6.9 -E- graphic symbols................... 6.8 Electric Binary Signal identification.........................5.1 66 ANSI/ISA-S5.1-1984 (R 1992) Term Para. No. Term Para. No. -H- Level Hand (Manually Actuated) graphic symbol.....................6.8, 6.6 example................................ 6.9 identification.........................5.1 graphic symbols................... 6.6 Light identification......................... 5.1 example................................6.9 Hand Wheel graphic symbol.....................6.3 graphic symbol..................... 6.5 identification.........................5.1 High Local (Field) identification......................... 5.1 definition............................... 3 High Limiting graphic symbol.....................6.3 graphic symbol..................... 5.4 Local Panel High Selecting definition............................... 3 graphic symbol..................... 5.4 identification.........................6.3 Hydraulic Signal Loop graphic symbol..................... 6.2 definition............................... 3 Hydraulic Supply identification.........................4.3 identification......................... 6.2 Louver -I- see Damper Identification Low combinations example......... 5.3 example................................6.9 definition............................... 3 identification.........................5.1 letters................................... 5.1 Low Limiting Indicate graphic symbol.....................5.4 example................................ 6.9 Low Selecting identification......................... 5.1 graphic symbol.....................5.4 Instrument -M- definition............................... 3 Manual Loading Station Instrument Air definition............................... 3 identification......................... 6.2 Measurement Instrumentation definition............................... 3 definition............................... 3 Mechanical Analysis Instrument Line Symbols........... 6.2 identification.........................5.1 Integral Mechanical Link graphic symbol..................... 5.4 graphic symbol.....................6.2 Integrate Middle (Intermediate) example................................ 6.9 identification.........................5.1 identification......................... 5.1 Moisture Interlock see Analysis example................................ 6.9 Momentary graphic symbol..................... 6.3 identification.........................5.1 -L- Monitor Letter Combinations................... 5.3 definition............................... 3 ANSI/ISA-S5.1-1984 (R 1992) 67 Term Para. No. Term Para. No. Multifunction Power example................................ 6.9 graphic symbol.....................6.8 identification......................... 5.1 identification........................ 5.1 Multiplying Presence graphic symbol..................... 5.4 identification.........................5.1 Multivariable Pressure Relief Valves graphic symbols................... 6.8 see Safety Relief Valves identification......................... 5.1 Pressure (or Vacuum) -N- graphic symbols................... 6.6, 6.8 Nitrogen Supply identification.........................5.1 identification......................... 6.2 Print Non-Linear example................................6.9 graphic symbol..................... 5.4 Primary Element (Sensor) -O- definition............................... see Sensor Orifice graphic symbols................... 6.8 identification......................... 5.1 Process Orifice Plate Taps definition............................... 3 graphic symbols................... 6.8 Process Variable -P- definition............................... 3 Panel (Board) Program (Primary Location) definition............................... 3 definition............................... 3 Programmable Logic graphic symbols................... 6.3 Controller Panel-Mounted definition............................... 3 (Board-Mounted) example................................6.10, 6.11 definition............................... 3 graphic symbol.....................6.3 graphic symbols................... 6.3 Proportional Pilot Light graphic symbol.....................5.4 definition............................... 3 Purge graphic symbol..................... 6.3 example................................6.10 identification......................... 5.1 graphic symbol.....................6.3 Plant Air -Q- identification......................... 6.2 Quantity Pneumatic Binary Signal examples.............................. 6.9 graphic symbol..................... 6.2 graphic symbols................... 6.8 Pneumatic Signal identification.........................5.1 graphic symbol..................... 6.2 -R- Point (Test) Radiation example................................ 6.9 graphic symbol.....................6.8 identification......................... 5.1 Ratio Position example................................6.9 graphic symbol..................... 6.8 identification.........................5.1 identification......................... 5.1 68 ANSI/ISA-S5.1-1984 (R 1992) Term Para. No. Term Para. No. Record graphic symbols................... 6.3 example................................ 6.9 Sight Glass identification......................... 5.1 graphic symbol.....................6.6 Relay Signal Monitor definition............................... 3 graphic symbol.....................5.4 examples.............................. 6.9 Simplified Diagram graphic symbols................... 5.4 example................................6.12 Relief Valve Solenoid see Safety Relief Valve graphic symbol.....................6.5 Reset Specific Gravity graphic symbol..................... 6.3 example................................6.8 Restriction Orifice Speed graphic symbol..................... 6.6 identification.........................5.1 Reverse Proportional Steam Supply graphic symbol..................... 5.4 identification.........................6.2 Root Extraction Straightening Vane graphic symbol..................... 5.4 graphic symbol.....................6.6 Rupture Disc Summing graphic symbols................... 6.6 graphic symbol.....................5.4 -S- Switch Safety definition............................... 3 identification......................... 5.1 example................................6.9 Safety Purging identification.........................5.1 example................................ 6.10 -T- Safety Relief Valves Temperature graphic symbols................... 6.6 graphic symbols................... 6.8 Scan identification.........................5.1 definition............................... 3 Test Point example................................ 6.9 definition............................... 3 identification......................... 5.1 example................................6.9 Self-Actuated Devices identification.........................5.1 graphic symbols................... 6.6 Time Function identification......................... 4.2.5 graphic symbol..................... 5.4 Sensor (Primary Element) Time Rate of Change definition............................... 3 identification.........................5.1 graphic symbols................... 6.8 Time, Time Schedule Set Point graphic symbols................... 6.8 definition............................... 3 identification.........................5.1 Shared Controller Totalize definition............................... 3 see Integrate graphic symbols................... 6.3 Transducer Shared Display definition............................... 3 definition.............................. 3 Transmitter ANSI/ISA-S5.1-1984 (R 1992) 69 Term Para. No. - Z- definition............................... 3 Z-Axis example................................ 6.9 identification.........................5.1 identification......................... 5.1 Traps example................................ 6.6 Typical Letter Combinations....................... 5.3 -U- Unclassified identification......................... 5.1 Undefined Signal graphic symbols................... 6.2 User's Choice examples.............................. 6.8 identification......................... 5.1 -V- Vacuum see Pressure Valve see Control Valve Velocity Limiter graphic symbol..................... 5.4 Vibration identification......................... 5.1 Voltage graphic symbols................... 6.8 identification......................... 5.1 -W- Water Supply identification......................... 6.2 Weight identification......................... 5.1 Well graphic symbols................... 6.8 identification......................... 5.1 -X- X-Axis identification......................... 5.1 -Y- Y-Axis identification......................... 5.1 70 ANSI/ISA-S5.1-1984 (R 1992) Developing and promulgating technically sound consensus standards, recommended practices, and technical reports is one of ISA's primary goals. 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