1、Annunciator Sequencesand SpecificationsReaffirmed 25 February 2004ISA-18.1-1979 (R2004) Formerly ISA-18.1-1979 (R1992)STANDARDISA The Instrumentation,Systems, andAutomation Society TMCopyright 1979 by the Instrument Society of America. All rights reserved. Printed in the UnitedStates of America. No
2、part of this publication may be reproduced, stored in a retrieval system, ortransmitted in any form or by any means (electronic, mechanical, photocopying, recording, orotherwise), without the prior written permission of the publisher.ISA67 Alexander DriveP.O. Box 12277Research Triangle Park, North C
3、arolina 27709ISA-18.1-1979 (R2004)Annunciator Sequences and SpecificationsISBN 0-87664-346-2ISA-18.1-1979 (R2004) 3PrefaceThis preface is included for informational purposes and is not part of ISA-18.1-1979 (R2004).This standard has been prepared as part of the service of ISA toward a goal of unifor
4、mity 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 Alexande
5、r Drive, P.O. Box 12277, Research Triangle Park, North Carolina 27709, Telephone (919) 549-8411, e-mail: standardsisa.org.Based on work started in 1955 by a survey committee titled Instrument Alarms and Interlocks, the 8D-RP18 Committee on Annunciator Systems of the Production Processes was formed i
6、n 1969. Tentative Recommended Practice ISA-RP18.1, titled Specifications and Guides for the Use of General Purpose Annunciators, was completed by that Committee in 1965.The committee, reactivated as Committee SP18, Instrument Signals and Alarms, began revising ISA-RP18.1 in 1976 to reflect current i
7、ndustry practice for annunciators; in 1991, the Nuclear Power Plant Standards Committee, SP67, assumed responsibility for the reaffirmation of this standard.It is the policy of ISA to encourage and welcome the participation of all concerned individuals and interests in the development of ISA standar
8、ds. Participation in the ISA standards-making process by an individual in no way constitutes endorsement by the employers of the 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 i
9、s not a part of the standard.The following people served as members of SP18 at the time of this standards 2004 reaffirmation:NAME COMPANYE. Icayan, Managing Director ACES Inc.A. Boquiren* Bechtel Corp. Control SystemsM. Casiglio HF ControlsD. Dunn EquistarM. Hanson Meyer Control Corp.W. Henderson* W
10、estinghouse Savannah River Co.C. Mastromonico* Westinghouse Savannah River Co.L. McAdams Bechtel National Inc.N.Shah* Bechtel Corp.S. Wright BNFL Inc._* One vote per company4 ISA-18.1-1979 (R2004)This reaffirmed standard was approved for publication by the ISA Standards and Practices Board in 2004.N
11、AME COMPANYV. Maggioli, Chairman Feltronics Corp.K. Bond ConsultantD. Bishop David N. Bishop, ConsultantD. Bouchard PapricanM. Cohen ConsultantM. Coppler Ametek, Inc.B. Dumortier Schneider ElectricW. Holland ConsultantE. Icayan ACES, Inc.A. Iverson Ivy OptiksR. Jones Dow Chemical Co.T. McAvinew I ho
12、wever, detailed design requirements and documentation formats are beyond the scope of this Standard.3 Definition of termsThe following are terms and their definitions that have special meaning in relation to annunciators. Commonly used alternate terms are shown in parentheses. Defined terms used in
13、other definitions are in italics to provide a cross-reference.acknowledge: the sequence action that indicates recognition of a new alarm.active alarm point: see alarm point.alarm: 1. an abnormal process condition. 2. the sequence state when an abnormal process condition occurs. 3. a device that call
14、s attention to the existence of an abnormal process condition. See annunciator. Types of alarm include:momentary: an alarm that returns to normal before being acknowledged.maintained: an alarm that returns to normal after being acknowledged.alarm module (point or sequence module): a plug-in assembly
15、 containing the sequence logic circuit. Some alarm modules also contain visual display lamps or lamps and windows.alarm point: the sequence logic circuit, visual display, auxiliary devices, and internal wiring related to one visual display. Types of alarm point include:8 ISA-18.1-1979 (R2004)active:
16、 an alarm point that is wired internally and completely equipped. The win-dow is labeled to identify a specific monitored variable.spare: an alarm point that is wired internally and completely equipped. The win-dow is not labeled to identify a monitored variable.future (blank): an alarm point that i
17、s wired internally and equipped except for theplug-in alarm module. The window is not labeled to identify a monitored variable.alert: see process condition and sequence state.analog input point: an alarm point for use with an analog monitored variable signal, usually current or voltage. The logic ci
18、rcuit initiates an alarm when the analog signal is above or below a set point.annunciator: a device or group of devices that call attention to changes in process conditions that have occurred. An annunciator usually calls attention to abnormal process conditions, but may be used also to show normal
19、process status. Usually included are sequence logic circuits, labeled visual displays, audible devices, and manually operated pushbuttons.audible device: a device that calls attention by sound to the occurrence of abnormal process conditions. An audible device may also call attention to return to no
20、rmal conditions.audible device follower: see auxiliary output.automatic reset: see reset.auxiliary contact: see auxiliary output.auxiliary output (auxiliary contact): An output signal operated by a single alarm point or group of points for use with a remote device. Types of auxiliary output include:
21、field contact follower: an auxiliary output that operates while the field contact in-dicates an abnormal process condition.lamp follower: an auxiliary output that operates while the visual display lamps in-dicate an alarm, silenced, or acknowledged state.audible device follower (horn relay contact):
22、 an auxiliary output that operateswhile the common alarm audible device operates.reflash: an auxiliary output that operates when any one of a group of alarm pointsindicates an abnormal process condition. The output usually returns to normalbriefly when each alarm point changes to an abnormal process
23、 condition and re-turns to normal when all alarm points in the group indicate normal process condi-tions.blank alarm point: see alarm point.field contact (trouble or signal contact): the electrical contact of the device sensing the process condition. The contact is either open or closed. Annunciator
24、 field contacts are identified in relation to process conditions and annunciator operation, not the disconnected position of the devices. Types of field contact include:normally open (NO): a field contact that is open for a normal process conditionand closed when the process condition is abnormal.no
25、rmally closed (NC): A field contact that is closed for a normal process conditionand open when the process condition is abnormal.field contact follower: see auxiliary output.field contact voltage (trouble or signal contact voltage): the voltage applied to field contacts.ISA-18.1-1979 (R2004) 9first
26、alert: see first out.first out (first alert): a sequence feature that indicates which of a group of alarm points operated first.first out reset: see reset.flasher: a device that causes visual displays to turn on and off repeatedly. Types of flashing include fast flashing, flashing, slow flashing, an
27、d intermittent flashing.functional test: see test.future alarm point: see alarm point. horn relay contact: see auxiliary output.integral logic annunciator: an annunciator that includes visual displays and sequence logic circuits in one assembly.lamp cabinet: a cabinet containing visual displays only
28、.lamp follower: see auxiliary output.lamp test: see test.lock-in: a sequence feature that retains the alarm state until acknowledged when the abnormal process condition is momentary.logic cabinet: a cabinet containing logic circuits and no visual displays.maintained alarm: see alarm.manual reset: se
29、e reset.momentary alarm: see alarm.multiple input: see reflash.nameplate: see window.normally closed (NC): see field contact. normally open (NO): see field contact.operational test: see test.point module: see alarm module.process condition: the condition of the monitored variable. The process condit
30、ion is either normal or abnormal (alarm, alert, or off-normal).pushbutton: A momentary manual switch that causes a change from one sequence state to another. Pushbutton actions include silence, acknowledge, reset, first out reset, and test.reflash (multiple input): 1. an auxiliary logic circuit that
31、 allows two or more abnormal process conditions to initiate or reinitiate the alarm state of one alarm point at any time. The alarm point cannot return to normal until all related process conditions return to normal. 2. one type of auxiliary output.remote logic annunciator: an annunciator that locat
32、es visual displays and sequence logic circuits in separate assemblies.reset: the sequence action that returns the sequence to the normal state. Types of reset include:automatic: reset occurs after acknowledge when the process condition returns to normal.manual: reset occurs after acknowledge when th
33、e process condition has returnedto normal and the reset pushbutton is operated.10 ISA-18.1-1979 (R2004)first out: reset of the first out indication occurs when the acknowledge or first outreset pushbutton is operated, whether the process condition has returned to nor-mal or not, depending on the seq
34、uence.response time: the time period between the process condition becoming abnormal and initiation of the alarm state. The minimum momentary alarm duration required for annunciator operation.return alert: see ringback.ringback (return alert): a sequence feature that provides a distinct visual or au
35、dible indication or both when the process condition returns to normal.sequence: the chronological series of actions and states of an annunciator after an abnormal process condition or manual test initiation occurs.sequence action: a signal that causes the sequence to change from one sequence state t
36、o another. Sequence actions include process condition changes and manual operation of pushbuttons.sequence diagram: a graphic presentation that describes sequence actions and sequence states.sequence module: see alarm module.sequence state: the condition of the visual display and audible device prov
37、ided by an annunciator to indicate the process condition or pushbutton actions or both. Sequence states include normal, alarm (alert), silenced, acknowledged, and ringback.sequence table: a presentation that describes sequence actions and sequence states by lines of statements arranged in columns.si
38、gnal contact: see field contact.signal contact voltage: see field contact voltage.silence: the sequence action that stops the sound of the audible device.spare alarm point: see alarm point. test: an annunciator sequence initiated by operation of the test pushbutton to reveal lamp or circuit failure.
39、 Types of test include:operational (functional): test of the sequence, visual display lamps, audible de-vices, and pushbuttons.lamp: test of the visual display lamps.trouble contact: see field contact. trouble contact voltage: see field contact voltage.visual display: that part of an annunciator or
40、lamp cabinet that indicates the sequence state. Usually consists of an enclosure containing lamps behind a translucent window. The lamps can be off, flashing, or on.window (nameplate): a component of a visual display made from a translucent material that is illuminated from the rear and labeled to i
41、dentify the monitored variable.ISA-18.1-1979 (R2004) 114 Sequences4.1 OperationAnnunciators usually call attention to abnormal process conditions by the use of individual illuminated visual displays and audible devices. Annunciators may also be used to show normal process status. Changes from one an
42、nunciator sequence state to another are caused by changes in process conditions and also by manual operation of pushbuttons. The new sequence state may be dependent on the process condition that exists at the time pushbuttons are operated. Process condition changes are usually sensed by field contac
43、ts.The visual displays usually flash to indicate abnormal process conditions and change to on when alarms are acknowledged. Additional types of flashing can indicate that process conditions have returned to normal or which of a group of alarm points operated first. All of the alarm points of an annu
44、nciator usually use the same sequence; however, different sequences can be used for individual alarm points or groups of points in one annunciator.In this Standard, sequences making use of more than one indication device as a part of each visual display to indicate the sequence state are considered
45、to be special because of their many variations and relatively infrequent use. Examples include the use of lamps of different colors to indicate different sequence states or which is the first of a group of alarms.4.2 PresentationAnnunciator sequence tables describe the operation of annunciators, but
46、 often do not clearly indicate all aspects of the sequences. Examples include failure to indicate the sequence actions and states when process conditions return to abnormal again before the annunciator is reset and also when pushbuttons are operated out of the normal sequence. A sequence diagram for
47、mat is used in this Standard to allow annunciator sequences to be defined completely and analyzed logically. See Figures 2 to 8. Sequence diagrams include a block for each annunciator sequence state. The process condition, the sequence state, and the visual display and audible device conditions when
48、 in that state are indicated in each block. The blocks are arranged to describe the annunciator sequence from the normal state, through the other sequence states, and back to the normal state again. Arrows between the blocks indicate all possible sequence actions that can cause a change from one seq
49、uence state to another. Sequence actions include process condition changes and manual operation of pushbuttons.Sequence tables are also used in this Standard since it is not always convenient to use sequence diagrams. These sequence tables are patterned after the sequence diagrams to describe all aspects of the annunciator operation. See Figures 2 to 8.The sequence tables include a line for the initial normal state and also a line for each possible sequence action that can cause a change from one sequence state to another. The reference line numbers in the tables are ide
