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    AMERICAN NATIONAL STANDARD

    ANSI/ISA-5.06.01-2007

    Functional Requirements Documentationfor Control Software Applications

    Approved 29 October 2007

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    ANSI/ISA-5.06.01-2007Functional Requirements Documentation for Control Software Applications

    ISBN: 978-1-934394-33-5

    Copyright 2007 by ISA. All rights reserved. Not for resale. 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.

    ISA67 Alexander DriveP.O. Box 12277Research Triangle Park, North Carolina 27709

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    3 ANSI/ISA-5.06.01-2007

    Copyright 2007 ISA. All rights reserved.

    Preface

    This preface, as well as all footnotes and annexes, is included for information purposes and is not part ofANSI/ISA-5.06.01-2007.

    This document has been prepared as part of the service of ISA toward a goal of uniformity in the field ofinstrumentation. To be of real value, this document should not be static but should be subject to periodicreview. Toward this end, the Society welcomes all comments and criticisms and asks that they beaddressed to the Secretary, Standards and Practices Board; ISA; 67 Alexander Drive; P. O. Box 12277;Research Triangle Park, NC 27709; Telephone (919) 549-8411; Fax (919) 549-8288; E-mail:[email protected].

    The ISA Standards and Practices Department is aware of the growing need for attention to the metricsystem of units in general, and the International System of Units (SI) in particular, in the preparation ofinstrumentation standards. The Department is further aware of the benefits to USA users of ISAstandards of incorporating suitable references to the SI (and the metric system) in their business andprofessional dealings with other countries. Toward this end, this Department will endeavor to introduceSI-acceptable metric units in all new and revised standards, recommended practices, and technical

    reports to the greatest extent possible. Standard for Use of the International System of Units (SI): TheModern Metric System, published by the American Society for Testing & Materials as IEEE/ASTM SI 10-97, and future revisions, will be the reference guide for definitions, symbols, abbreviations, andconversion factors.

    It is the policy of ISA to encourage and welcome the participation of all concerned individuals andinterests in the development of ISA standards, recommended practices, and technical reports.Participation in the ISA standards-making process by an individual in no way constitutes endorsement bythe employer of that individual, of ISA, or of any of the standards, recommended practices, and technicalreports that ISA develops.

    CAUTION ISA ADHERES TO THE POLICY OF THE AMERICAN NATIONAL STANDARDSINSTITUTE WITH REGARD TO PATENTS. IF ISA IS INFORMED OF AN EXISTING PATENT THAT ISREQUIRED FOR USE OF THE DOCUMENT, IT WILL REQUIRE THE OWNER OF THE PATENT TOEITHER GRANT A ROYALTY-FREE LICENSE FOR USE OF THE PATENT BY USERS COMPLYINGWITH THE DOCUMENT OR A LICENSE ON REASONABLE TERMS AND CONDITIONS THAT AREFREE FROM UNFAIR DISCRIMINATION.

    EVEN IF ISA IS UNAWARE OF ANY PATENT COVERING THIS DOCUMENT, THE USER ISCAUTIONED THAT IMPLEMENTATION OF THE DOCUMENT MAY REQUIRE USE OF TECHNIQUES,PROCESSES, OR MATERIALS COVERED BY PATENT RIGHTS. ISA TAKES NO POSITION ON THEEXISTENCE OR VALIDITY OF ANY PATENT RIGHTS THAT MAY BE INVOLVED IN IMPLEMENTINGTHE DOCUMENT. ISA IS NOT RESPONSIBLE FOR IDENTIFYING ALL PATENTS THAT MAYREQUIRE A LICENSE BEFORE IMPLEMENTATION OF THE DOCUMENT OR FOR INVESTIGATINGTHE VALIDITY OR SCOPE OF ANY PATENTS BROUGHT TO ITS ATTENTION. THE USER SHOULDCAREFULLY INVESTIGATE RELEVANT PATENTS BEFORE USING THE DOCUMENT FOR THEUSERS INTENDED APPLICATION.

    HOWEVER, ISA ASKS THAT ANYONE REVIEWING THIS DOCUMENT WHO IS AWARE OF ANYPATENTS THAT MAY IMPACT IMPLEMENTATION OF THE DOCUMENT NOTIFY THE ISASTANDARDS AND PRACTICES DEPARTMENT OF THE PATENT AND ITS OWNER.

    ADDITIONALLY, THE USE OF THIS DOCUMENT MAY INVOLVE HAZARDOUS MATERIALS,OPERATIONS OR EQUIPMENT. THE DOCUMENT CANNOT ANTICIPATE ALL POSSIBLE

    APPLICATIONS OR ADDRESS ALL POSSIBLE SAFETY ISSUES ASSOCIATED WITH USE INHAZARDOUS CONDITIONS. THE USER OF THIS DOCUMENT MUST EXERCISE SOUND

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    ANSI/ISA-5.06.01-2007 4

    Copyright 2007 ISA. All rights reserved.

    PROFESSIONAL JUDGMENT CONCERNING ITS USE AND APPLICABILITY UNDER THE USERSPARTICULAR CIRCUMSTANCES. THE USER MUST ALSO CONSIDER THE APPLICABILITY OF

    ANY GOVERNMENTAL REGULATORY LIMITATIONS AND ESTABLISHED SAFETY AND HEALTHPRACTICES BEFORE IMPLEMENTING THIS DOCUMENT.

    THE USER OF THIS DOCUMENT SHOULD BE AWARE THAT THIS DOCUMENT MAY BE IMPACTED

    BY ELECTRONIC SECURITY ISSUES. THE COMMITTEE HAS NOT YET ADDRESSED THEPOTENTIAL ISSUES IN THIS VERSION.

    The following members of ISA5.6 contributed to the development of this standard:

    NAME AFFILIATION

    A. Habib, Chair Automation ConsultantA. Amdur ConsultantD. Beaty DLB AssociatesP. Blok Pharma Team USAR. Dwiggins Maverick TechnologiesJ. Halajko FMC, Inc.

    R. Bhala Sanofi PasteurS. Kolla Bowling Green State UniversityR. Topliff CH2M HILLR. Wood University of Alberta

    The following people served as voting members of ISA5:

    NAME AFFILIATION

    A. Iverson, Chair Ivy OpticsT. McAvinew, Managing Director Jacobs Engineering

    G. Barta ConsultantC. Borel Spectrum Engineering Inc.J. Carew Consultant

    A. Habib Automation ConsultantG. Ramachandran Motiva Enterprises LLC

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    This standard was approved for publication by the ISA Standards and Practices Board on 17 August2007.

    NAME AFFILIATION

    T. McAvinew, Vice President Jacobs Engineering GroupM. Coppler Ametek Inc.E. Cosman The Dow Chemical CompanyB. Dumortier Schneider ElectricD. Dunn Aramco Services Co.J. Gilsinn NISTW. Holland ConsultantE. Icayan ACES Inc.J. Jamison Jamison & Associates LtdR. Jones CDI Business SolutionsK. Lindner Endress + Hauser Process SolutionsV. Maggioli Feltronics Corp.

    A. McCauley, Jr. Chagrin Valley Controls Inc.G. McFarland Emerson Process ManagementR. Reimer Rockwell AutomationN. Sands E I du PontH. Sasajima Yamatake Corp.T. Schnaare Rosemount Inc.J. Tatera Tatera & AssociatesI. Verhappen MTL Instrument GroupR. Webb ConsultantW. Weidman Parsons Energy & Chemicals GroupJ. Weiss Applied Control Solutions LLCM. Widmeyer ConsultantM. Zielinski Emerson Process Management

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    7 ANSI/ISA5.06.012007

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    Contents

    Preface .......................................................................................................................................................... 3

    1 Scope .................................................................................................................................................11

    2 Normative References........................................................................................................................12

    3 Definitions/Abbreviations....................................................................................................................13

    4 Methodology.......................................................................................................................................14

    4.1 Modular plant arrangement........................................................................................................14

    Annex A (informative) Application Example 1: Batch Reactor ...............................................................27

    Annex B (informative) -- Application Example 2: Continuous Distillation Column...................................43

    Figure 1 Charter upon which this standard is based..............................................................................12

    Figure 2 Modular plant partitioning.........................................................................................................15

    Figure 3 Four components of software documentation methodology ....................................................16

    Figure 4 Example of modular plant partitioning and software documentation.......................................17

    Figure 5 Database documentation .........................................................................................................18

    Figure 6 Interlock matrix documentation ................................................................................................21

    Figure 7a Normal sequence matrix ........................................................................................................22

    Figure 7b Hold sequence matrix ............................................................................................................23

    Figure 7c Recipe sequence matrix.........................................................................................................23

    Figure 8 Data security definition.............................................................................................................25

    Figure 9 Chemical reactor P&ID.............................................................................................................27

    Figure 10a Database I/O information.....................................................................................................29

    Figure 10b Database HMI information ...................................................................................................30

    Figure 10c Database operating information...........................................................................................31

    Figure 10d Control module class definition ............................................................................................32

    Figure 11a Software interlock matrix for Unit R-101 ..............................................................................33

    Figure 11b Software interlock matrix for Equipment Module EM-1........................................................34

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    Figure 12a Normal sequence matrix for Unit R-101...............................................................................36

    Figure 12b Hold sequence matrix for Unit R-101...................................................................................37

    Figure 12c Recipe sequence matrix for R-101.......................................................................................38

    Figure 12d Equipment module sequence matrix for EM-1 phase FILL_R101.......................................39

    Figure 13a Graphic elements.................................................................................................................40

    Figure 13b Interlock status display.........................................................................................................41

    Figure 13c Sequence status display ...................................................................................................... 41

    Figure 14 Continuous Distillation Column P&ID.....................................................................................44

    Figure 15a Database I/O information.....................................................................................................46

    Figure 15b Database HMI information ...................................................................................................47

    Figure 15c Database operating information...........................................................................................48

    Figure 16 Interlock matrix.......................................................................................................................49

    Figure 17a Normal sequence matrix for Unit C-104 (URS format) ........................................................51

    Figure 17b Hold sequence matrix for Unit C-104 (URS format).............................................................52

    Figure 17c Sequence matrix for C-104 Startup phase in FRS format (continues on next page)...........53

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    Foreword

    Learning and configuring today's control software packages is easier than ever before. Documentation,however, is not such an easy task. With the increased capabilities of software packages to handle moreprocess and operator interfaces, the complexity of defining and documenting these requirements

    increases. This standard directly addresses this documentation issue.

    The ISA5.6 subcommittee was established by ISA5, Documentation of Measurement and ControlInstruments and Systems, at the request of control systems engineers involved in the automation of plantoperations using a wide variety of computer-based platforms. These platforms included distributed controlsystems, programmable logic controllers and industrialized personal computers offered by a variety ofsuppliers.

    The need for documentation to help define control software prior to hardware selection, especially for batchsequence logic, was identified due to its complexity. ISA's Standards & Practices Board subsequentlyexpanded the scope of ISA5.6 to include the software documentation of continuous processes.

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    1 Scope

    The scope of this standard is:

    Covers real-time batch, discrete and continuous process automation systems.

    Defines regulatory, event-driven and time-driven control system actions.

    Encompasses both digital and analog control devices in addition to non-control actions (for example,operator messages and batch end reports).

    Encompasses both normal and abnormal operational requirements of systems and shows theinteractions between them.

    Uses a set of terms that relate directly to the languages commonly used by plant operators.

    Excludes interactions with higher-level systems.

    Within the parameters of this scope, the standard is intended to:

    Establish functional requirements specifications for control software documentation that covers theclasses of industrial automation equipment and systems consisting of distributed control systems,programmable controllers and industrial personal computers (see Figure 1).

    Provide techniques for documenting control system software. The software to be generated is afunction of the computer system chosen for a particular project. The documentation procedure setforth in this standard is independent of the hardware/software system that is chosen.

    Provide a basis for validation of run-time application software after it is developed and tested toensure that the initial requirement specification has been met.

    The documentation resulting from use of this standard:

    Can be used for control software definition, design, testing and validation.

    Is not intended to require specialized knowledge of any particular engineering or computer sciencediscipline to develop or understand.

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    PharmaceuticalPharmaceutical

    PowerPower

    ChemicalChemical

    FoodFood

    AutomotiveAutomotive

    Many othersMany others

    IndustrialIndustrial

    Appl icati onsAppl icati onsISAISA--5.06.015.06.01

    UserUsers Softwares Software

    RequirementsRequirements

    DatabaseDatabase

    Interlock LogicInterlock Logic

    Sequence LogicSequence Logic

    ImplementationImplementation

    LanguagesLanguagesTargetTarget

    SystemsSystems

    Industrial PCIndustrial PCss

    ProgrammableProgrammable

    Logic ControllersLogic Controllers

    DistributedDistributedControl SystemsControl SystemsSequentialSequential

    FunctionFunction

    ChartChart

    VendorVendor

    LanguagesLanguages

    ProprietaryProprietary

    LanguagesLanguages

    Relay LadderRelay LadderHumanHuman--MachineMachine

    InterfaceInterface

    Figure 1 Charter upon which this standard is based.

    2 Normative References

    The following normative documents contain provisions that, through reference in this text, constituteprovisions of this standard. At the time of publication the editions indicated were valid. All normativedocuments are subject to revision and parties to agreements based on this standard are encouraged toinvestigate the possibility of applying the most recent editions of the normative documents indicatedbelow. Members of the IEC and ISO maintain registers of currently valid normative documents.

    ANSI/ISA-84.00.01-2004 Parts 1-3 (IEC 61511 Modified), Functional Safety: Safety InstrumentedSystems for the Process Industry Sector. www.isa.org .

    ISA-88.01-1995, Batch Control Part 1: Models and Terminology. www.isa.org.

    ISA-5.5-1985, Graphic Symbols for Process Displays. www.isa.org.

    IEC 61131-3 Ed. 2.0: 2003Programmable controllers - Part 3: Programming languages. www.iec.ch.

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    3 Definitions/Abbreviations

    3.1 analog input (AI):a modulated signal received by the control system from an external measurement device, such as a 420

    mA or fieldbus signal from a pressure transmitter.

    3.2 analog output (AO):a modulated signal sent by the control system to an external control device, such as an analog 420 mAor digital fieldbus signal to a flow control valve.

    3.3 control module (CM):the lowest level grouping of equipment in the physical model that can carry out basic control.

    NOTE This term applies to both the physical equipment and the equipment entity.

    3.4 detailed design specification (DDS):a separate document that shows how a system functions and meets the requirements laid out in the

    Functional Requirements Specification prepared from this document.

    3.5 discrete input (DI):a binary signal received by the control system from an external switch such as a 24-Vdc or fieldbus signalfrom a block valves closed limit switch.

    3.6 discrete output (DO):a binary signal sent by the control system to an external on/off device such as a 120-Vac or digitalfieldbus signal to start a pump.

    3.7 equipment module (EM):a functional group of equipment that can carry out a finite number of specific minor processing activities.This may exist as part of a unit or as a common resource -- e.g., equipment shared by two or more units.

    3.8 functional requirements specification (FRS):a specification listing the detailed operational requirements for a control system (i.e., what the systemdoes, not how it does it).

    3.9 operation:a major programmed processing action or set of related actions normally consisting of one or morephases.

    3.10 Piping and Instrumentation Diagram (P&ID):a diagram showing the interconnection of process equipment and instrumentation used to control aprocess.

    3.11 Process Flow Diagram (PFD):

    a diagram showing outlines of one or more pieces of equipment and the expected flow paths for materialsand utilities.

    3.12 phase:the smallest element of procedural control that can accomplish a process-oriented task. A phase may becomprised of steps.

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    3.13 process cell:a logical grouping of equipment that includes the equipment required for production of one or morematerials. It defines the span of a logical control of one set of process equipment within an area.

    3.14 step:sequential action of control devices within a phase (shown in this standard by a number in parenthesesafter the status for a discrete device or setpoint for an analog device).

    3.15 train:a collection of one or more units and associated lower-level equipment groupings that has the ability to beused to make a quantity of material.

    3.16 unit:an equipment grouping to carry out one or more major processing activities such as reaction,crystallization and making a solution. It combines all necessary physical processing and controlequipment required to perform those activities as an independent equipment grouping. It is usuallycentered on a major piece of processing equipment such as a mixing tank or reactor.

    3.17 User Requirements Specification (URS):a specification showing the general control requirements for a unit or process cell.

    4 Methodology

    4.1 Modular plant arrangement

    The first step in applying this standard is to divide a process plant into the groupings illustrated in Figure2. Classes of process units are grouped vertically and trains are grouped horizontally in the figure.Examples of process units include reactors, distillation columns and dryers. A train consists of one ormore units necessary to complete the processing step for an intermediate or finished product. This maybe as simple as a single mix tank and as complex as a refinery train consisting of multiple reactors,distillation units, dryers, etc. For flexible batch operations we may not be able to define trains other thanas individual units. The boxes shown on the periphery of Figure 2 are shared resources comprisingadditional units and/or equipment modules.

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    Gas Waste Treatment

    Units

    Train # A B C D E

    S

    T

    OR

    A

    G

    E

    S

    T

    OR

    A

    G

    E

    U

    T

    IL

    I

    T

    I

    ES

    P

    A

    C

    K

    AG

    IN

    G

    Liquid & Solid Waste Treatment

    RawMaterials

    Product

    Shipping

    Discharge

    Discharge

    Figure 2 Modular plant partitioning

    This approach has benefits when configuring both the hardware and the software of a control system.Maximizing the separation of control hardware between trains will minimize the production impact of ahardware failure, while maximizing similarity within each class of process units will minimizeimplementation costs and human errors in both design and operation. The latter is accomplished byemploying reusable design features wherever possible by means of standard class definitions (for units,

    equipment modules, control modules, etc.) that can be completed and validated for one instance, thencopied or instantiated and quickly validated for the remaining members of each class.

    Depending on the needs of the design team, the initial design may utilize a User RequirementsSpecification (URS). This outlines the process control needs for the process cell being designed. Astandard Piping and Instrumentation Drawing (P&ID) and instrument index may provide all of thenecessary information. Alternatively, more detail as shown on the matrices below may be desired at thisstage. The URS is often adequate for review by plant operations, maintenance and process engineeringpersonnel.

    After the design basis of the process cell is settled, the basic documentation such as process flowdiagram, P&ID, instrument index and preliminary equipment design can be completed. If adequate, asnoted above, these will comprise the URS.

    The next step is to develop four basic elements of the Functional Requirements Specification (FRS) thatdescribe the instances and detailed requirements for each class of objects so defined (see Figure 3). TheFunctional Requirements Specification (FRS) is much more detailed and is utilized by instrumentationand system integration personnel as well as during process safety reviews. The four elements of the FRSare:

    Database (instrument tag table)

    Interlock matrix (interlock logic)

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    Sequence matrix (sequence logic)

    Human Machine Interface (HMI)

    The first three are commonly prepared using spreadsheet software. The fourth will use graphicalsoftware. Examples of each are shown in the examples that follow this description.

    DatabaseDatabase

    Interlock M atrixInterlock M atrix

    Sequence M atrixSequence M atrix

    HumanHuman --M achine InterfaceM achine Interface

    Figure 3 Four components of software documentation methodology

    Developing these FRS elements assumes that the equipment and processing requirements are welldefined. The necessary information can normally be found on various drawings (such as PFDs, P&IDs,and equipment drawings), equipment specifications and data sheets, and other sources. Classes ofcontrol objects to supply the required functionality can be developed as needed or drawn from an existingarchive.

    Figure 4 illustrates the connection between typical units and modules of a partitioned modular plant andthe four basic FRS elements. As shown, a single FRS can describe an entire facility or a select subset asrequired by the project scope. Likewise, certain aspects such as the Sequence matrix may be omittedfrom the FRS if they are to be deferred to a separate project or provided by a different supplier.

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    Raw

    Materials

    Gas Waste Treatment

    UnitsTrain

    #S

    T

    O

    R

    A

    G

    E

    S

    T

    O

    R

    A

    G

    E

    U

    T

    I

    L

    I

    T

    I

    E

    S

    P

    A

    C

    K

    A

    G

    I

    N

    G

    Liquid & Solid Waste Treatment

    Product

    Shipping

    Discharge

    Discharge

    Blender Reactor Centrifuge Distn Coln Dryer

    1

    2

    3

    4

    BL-101

    BL-201

    BL-401

    RX-102

    RX-202

    RX-302

    CE-103

    CE-303

    CE-403

    DI-104

    DI-204

    DI-304

    DR-105

    DR-205

    DR-405

    Database

    Interlock Matrix

    Sequence Matrix

    Human-Machine Interface

    Figure 4 Example of modular plant partitioning and software documentation

    4.1.1 Database

    The first part of the documentation is the database, which can be tabulated under various columnheadings as illustrated in Figure 5. This closely resembles the instrumentation index with provision torecord details of Input/Output (I/O) functionality and the parameters required to support operator displays,alarms and control loops. System-dependent implementation details will be defined in the Detailed DesignSpecification (DDS) which follows later. Though system specific, I/O hardware and software addressesare often considered as a functional requirement because of their potential impact on process availability;as such, they may be designated in the FRS after selection of the control system.

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    Figure 5 Database documentation

    The five sections of the database shown in Figure 5 can be consecutive column headings across aspreadsheet. They are shown here as separate sections of the table due to space limitations. In actualuse on a spreadsheet they will all follow left to right on one table. The separate sections shown here maybe useful for breaking out the table for a printed copy. Leaving this as a continuous spreadsheet will makeusing it easier. Each row would then show the relevant information for a single instrument or controlmodule; associated alarms may be designated using multiple entries per cell, additional columns orseparate tags. This document is the cornerstone of the FRS because it forms the basis or foundation forthe other documents that follow. It is applicable for both continuous and batch control but typically

    contains many more internal variables when applied to a batch process.

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    The column names for the database (Figure 5) are suggestions only. Depending on the system, softwareto be used and other parameters, columns may need to be added, deleted or renamed. The planned usesfor each column are:

    Basic Point DataCM Tag: the control module name usually corresponding to the instrument tag number shown on theP&ID, instrument index, etc.

    Service: the piece of equipment or module with which the instrument or loop is most closely associated.

    Location: the Unit or Equipment Module that includes the Control Module.

    P&ID: the Piping and Instrumentation Drawing showing the instrument or loop.

    Comments: provides additional information, if needed, for the instrument; may identify special or atypicalfeature requirements (not used in the examples that follow).

    I/O Interface Data

    Point Type: indicates the functionality of the item i.e., discrete vs. analog vs. digital, control vs. alarm,

    and input vs. output; optionally may refer to a separately specified class of control modules, equipmentmodules or units.

    Device Type: provides additional description of the item such as valve, motor starter, software / functionblock and may note signal conditioning such as characterization (chr) or square root extraction () to beperformed within the field device.

    Signal Type: shows type of signal for the I/O loop.

    Signal Condition ing: shows any adjustments that must be made to the input signal for the desiredcontrol action--i.e., pressure or temperature linearization, square-root extraction.

    I/O Tags: shows all P&ID tags associated with a particular control module.

    I/O Address: hardware or software address information; cabinet location and software identification fortroubleshooting, etc.

    Human/Machine Interface Data

    Scale: the zero and full-scale values or enumerated state descriptors for each signal.

    Eng Units: unit descriptor to accompany the value display.

    Descriptor: the full description of the instrument or loop for use on alarm and event lists, point details andother displays having sufficient space.

    Keywords: the abbreviated description of the instrument or loop for use on group displays and othershaving limited space.

    Data Logging & Archival:This is initially just a yes/no flag indicating if this control module should havedata logging and/or archiving capability. Later, this can be expanded to show the frequency of thesefunctions.

    Operating Data

    Alarm Type: identifies the type of each required alarm, such as bad value, high, and hihi for an analogdata point or command disagree and un-commanded change for a digital loop.

    Alarm Setpoint : the reading values that will activate the alarms, usually just one for each value, but mayspecify that it will be written or activated by a recipe or sequence logic.

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    Alarm Prior ity: the level of urgency to relay to the operator: different alarms within a loop can havedifferent priorities.

    Output Direction: defines the relationship between the controller output and the final control element(direct or reverse).

    Controller Type: manual, automatic and supervisory.

    Controller Algorithm: proportional, integral, derivative and combinations desired for the controlfunctioning.

    Controller Action: direct or reverse action of the controller output in response to the controlled variable--i.e., increasing or decreasing as the process value increases above the setpoint.

    Note Data access rights are presented in the HMI data security section while alarm deadbands are typically noted per point only

    upon exception to a percentage value footnoted on the database table. A further important part of the control database definition is

    specifying the instance-independent functionality for each class of control modules that will be referenced in the database matrix. A

    typical definition is illustrated in Figure 10d as part of the first application example. The corresponding control logic can ultimately be

    configured through any one or more of the following control language types: Boolean, function blocks, structured text, ladder logic

    and others.

    4.1.2 Process Interlock Matrix

    Next is the process interlock matrix illustrated in Figure 6. This contains the documentation for all of theprocess and safety interlocks in a particular section of the plant or project. It may be desirable to keep thesafety interlock documentation separate from the process interlocks. Showing both here will help assurethat all process concerns are addressed. The purpose here is to document the continuous interlockrequirements within the control system regardless of whether the process is continuous or batch.Continuous timed sequences (such as for a sump pump or for baghouse blowdown valves) may bedefined here or in the sequence matrix depending upon complexity and safety impact. Product-dependenttrip points (such as reactor temperature limits) will normally be identified in the sequence matrix with theassociated actions defined either here or in the sequence matrix.

    The interlock logic can be described in a simple table listing the interlock numbers taken from the P&ID(piping and instrumentation diagram) or equivalent document along with the initiating device(s) andcontrol device(s). Examples of these include a temperature switch, proximity sensor and block valve.

    The P&ID presentation below graphically illustrates the different hardware and software components usedto interlock the normal control function (HS-104) with a low level switch (LSLL-101) acting on the finalcontrol element (SV-104) using the software logic solver (UC-104).

    The company that will be operating the system defines the hazard level. Some examples of hazard levelsdefined by the potential for material, equipment and personnel loss are shown below. Further informationcan be found in Guidelines for Safe Automation of Chemical Processes (see section 2), AIChE / CCPS,1993, www.aiche.org. Guidance for the choice of interlocks, their logic and setting the Safety IntegrityLevel is found in ANSI/ISA-84.00.01-2004 Parts 1-3 (IEC 61511 Modified), Functional Safety: SafetyInstrumented Systems for the Process Industry Sector. www.isa.org .

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    INITIATINGDEVICE (FAULT)

    CONTROL DEVICE(ACTION)ID

    NUMBER

    SET POINTS LOGIC

    HAZARDLEVEL

    SAFETYINTEGRITY

    LEVEL

    OPERATINGMODE

    INTERLOCKPURPOSE

    Figure 6 Interlock matrix documentation

    Sample Definitions:

    Hazard Level: Material Loss Equipment Loss Personnel Loss

    (0) None(1) Low Recoverable Repairable Damage Medical Treatment(2) Medium Batch Lost Replace Unit Lost Time Accident(3) High Other Batches Lost Replace Other Units Mult. Injury or Death

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    Safety Integrity Levels--Examples:

    (1) One sensor, one logic solver, one actuator(2) Two sensors, two logic solvers, one actuator

    (3) Two sensors, two logic solvers, two actuators

    Operating Modes

    *AR = Automatic reset

    *R = Manual reset

    *V = Override (with pre-set timer)

    *B = Bypass (forcing, testing)

    The process safety team should review this simple list before the actual software configuration isdeveloped. These interlocks may be modified based on the results of a hazard analysis for the unit.

    4.1.3 Sequence Matrix

    The sequence operation of the process is then documented. This may be accomplished with thesequence matrix (see Figures 7a, 7b, and 7c). This information can also be presented using sequentialfunction charts, relay ladder logic and other formats. Here we show the matrix as prepared on aspreadsheet. The sequence matrix has three main sections:

    Normal sequence matrix

    Hold sequence matrix Recipe sequence matrix

    Figure 7a Normal sequence matrix

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    Figure 7b Hold sequence matrix

    RECIPE INITIAL OPERATIONS SHUT- CHANGE CONTROL

    PARAMETERS PHASE PHASE PHASE PHASE PHASE PHASE DOWN DESCRIPTION DATE

    PHASE

    VARIABLES CODED IN PROGRAM

    VARIABLES ENTERED BY OPERATOR

    VARIABLES ENTERED BY PRODUCTION SUPERVISOR

    Figure 7c Recipe sequence matrix

    A Sequence matrix can be developed for either a continuous or batch process as shown in the examplesto follow. It will typically be much simpler for a continuous process and may not have a recipe matrix. The

    sequence matrix can be used to specify the following types of control requirements:

    State definitions and allowed transitions for control modules (CM), equipment modules (EM), units, orclasses of like CM, EM, or units whose instances have been identified in the database and/orinterlock matrix (usually oriented toward low-level equipment functions requiring little product-specificknowledge; operators, interlocks or phase logic initiate all state transitions; class definitions should bereusable from project to project).

    Sequence definition and parameter identification for phases or classes of like phases whoseinstances are identified relative to a particular EM, unit or class of like EM or units referenced in the

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    database (usually oriented toward minor processing functions requiring little product-specificknowledge; typically interfaces to field devices indirectly by manipulating CM and/or EM states;operators or recipe sequences initiate phase execution; class definitions for common requirementsshould be reusable from project to project).

    Definition of phase sequencing, equipment requirements/arbitration and process parametersnecessary to manufacture each product or class of products (coordinates all product-specific control

    requirements; operator or higher-level scheduling systems initiate recipe execution)

    Accommodation of both normal and abnormal process conditions for each of the above includinghierarchical propagation of consequential actions as needed.

    Preparing the product-specific requirements necessitates a detailed knowledge of the operations to beconducted in the subject equipment. Typically, a process write-up or batch sheet and standard operatingprocedure will provide the necessary knowledge. Using common or generic terms for the phase nameswill make this document more understandable for others who use it. Sample operation names include:prepare, react, distill, extract, solvent strip, clean and shutdown. Typical phase names include: initial, fill,mix, heat, cure, settle, drain/dump and transfer. The user can employ these or other names asappropriate. These names need to be clearly understood by the plant personnel.

    One or more phases may require that multiple actions be completed in order to satisfy the phaserequirements. These multiple actions are called steps. All of these steps are typically shown in onecolumn of the spreadsheet. The order in which these must be satisfied is indicated with numbers inparenthesis after the listed action. Where additional distinction between the steps is necessary thecolumn under the phase can be split to show the different steps.

    If an equipment module is part of the unit, this will need to be shown in the sequence matrix. If theequipment module is shared by multiple units it will require its own matrix. Otherwise, its phases can beincorporated into the matrix for that unit. Two examples are a heating/cooling system for a reactor jacketand charging manifold with valves and a pump. Using an equipment module may simplify the softwareprogramming during integration.

    The Normal Sequence matrix (Figure 7a) provides information for all expected usual or routine

    operations. As indicated, it shows the expected operation of each discrete and analog device associatedwith the unit. Where there are particular conditions that must be met at the start or end of a phase theseshould be listed. These conditions include the setpoints of analog controls that must be satisfied as givenin the Recipe Sequence below.

    Operator messages will appear on the HMI (human-machine interface) to cue an activity by the operator.Batch report variables will be configured into reports to be prepared as hardcopy or electronic media. Ifmanual operations are required to complete the phase, an operator message will cue the personnel andwait for the appropriate response before continuing the phase processing.

    Two formats for the Sequence matrix are shown in the examples. The first contains less-detailedinformation and will often satisfy the needs of the URS. All of the operations, phases and steps can beshown; however, little detail of their functionality is possible here. Each phase occupies a single column in

    the spreadsheet. This provides a good overview of the control scheme. This does not contain sufficientdetail for an instrumentation engineer or system integrator.

    The second format provides the level of detail required by these last functions. The information for eachphase is detailed over several columns. It can show the details of each control function needed for thesystem to function. This level of detail is necessary for the FRS and is illustrated for just one of thephases in each example. It also provides the information needed to validate the operation of a controlsystem during start-up.

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    The Hold Sequence (Figure 7b) indicates which conditions are considered to be abnormal by the systemand the resulting actions in response to these conditions. If any of the abnormal conditions are met, thesystem will proceed to the condition shown under Hold Actions and the operator message will bedisplayed. When the abnormal condition no longer exists the Recovery status will be initiated if thesystem is in full automatic operation.

    The Recipe Sequence matrix (Figure 7c) may show general recipe information or have specificinformation for several recipes to be programmed for that unit. Each parameter needed for a recipe isshown with the permission level required by a person to enter or modify that parameter. Where there arelimits on a parameter for a specific phase, this is shown in the appropriate column. This helps prevententry of wrong values for the parameters.

    The allowable modes of operation for each phase include manual and automatic. Under automaticoperation, a recipe will proceed without operator interaction unless a hold condition occurs or interactionis required for a particular part of a phase.

    4.1.4 Human - Machine Interface (HMI)

    ISA-5.5-1985, Graphic Symbols for Process Displays, provides a good starting point in defining theshapes of process equipment for the dynamic graphic displays on operator console screens. It alsoprovides guidelines for use of color for graphic displays. Many hardware vendors have a built-in library ofISA symbols in their graphic display packages.

    In addition to displays that usually are supplied as standard with most systems such as controllerfaceplates, alarm summary displays and trend displays, custom displays may be required to facilitate theoperation of a control system. Examples include the interlock and sequence status displays shown inFigures 12b and 12c.

    An important part of the HMI definition is setting the data security and access levels. A typical definition isshown in Figure 8. Access needs to be set for different functions in the system such as changing loop setpoints and changing recipes by various personnel such as operators, supervisors and engineers. Forsome systems, many more access levels are available. A typical example of this is multiple operatorclasses with permissions limited by process area(s).

    PERSONNEL TYPEFUNCTION

    Operator Technician Supervisor Engineer

    Controller Tuning NO YES NO YES

    Controller SP Change YES YES YES YES

    Interlock Setting Change NO YES NO YES

    Alarm SP Change NO YES YES YES

    Recipe Selection NO NO YES YES

    Figure 8 Data securit y definit ion

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    Annex A (informative) Applicat ion Example 1: Batch Reactor

    The following chemical reactor example illustrates the application of the methodology to a simple batchprocess. As the P&ID shows (Figure 9), this reactor will fill multiple materials, heat, mix, and drainmaterial.

    REACTOR

    R-101

    101

    106

    105

    102

    PUMP

    P-104

    LI

    HS

    TT106

    TC

    TV

    106

    TAH

    TAHH

    104

    DRAIN

    STEAM

    HS

    HS

    REACTOR R-1

    P&ID

    DRAWING # P-101

    FILL A

    FILL B

    FILL C

    LT

    101

    001

    HS

    T CONDENSATE

    PUMPP-003

    003

    HSMIXER

    AG-102ZIC

    004A

    ZIC

    004C

    ZIC

    004B

    HS

    004

    003

    102

    104

    UC

    UC

    UC

    003

    FQC

    FV

    003

    002

    HS

    R-201

    101

    LSLL

    103

    LAHH

    101

    LSL

    FT

    003

    UNIT R-101SHARED EQUIPMENT MODULE EM -1

    LSHH

    103

    LAH

    LSHH-

    203

    I

    UNIT R-201

    XV

    001

    XV002

    I

    Note: XV limit switches and pump run indications

    are not shown here due to space limitations

    XV

    105

    Figure 9 Chemical reactor P&ID

    The raw material charging manifold and pump are treated as a shared equipment module (EM-1)

    because this feed system serves more than one reactor. Accordingly, the phase logic for EM-1 is definedin a separate, small sequence matrix whose operation is triggered by the batch recipe. The HS-004setpoint, which is also recipe-controlled, determines the proper position switch (ZIC-004A/B/C) alignmentand selectively enables the valve position alarms. All valves and other instruments for R-201 and EM-1are included in the full database matrix.

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    The database (Figures 10a, b and c) gives the information for each device on the P&ID in Figure 9. Thedigital control module classes identified in the Point Type column (Figure 10a) are functionally definedby the respective class details shown in Figure 10d.

    Initially, the I/O address column in Figure 10a may list only the number and type of connections asshown in Figure 10d. Later, this can be split into multiple columns as required by the system layout anddetails. These additional columns may show (1) the physical location of the cable connections (cabinetdata);(2) the logical connections to other control software;and (3) the software address as appropriateto the control system used for the particular process system.

    The HMI information for scale and engineering units (Figure 10b) will come from process information andpossibly equipment design limits. The keyword is necessary only if the HMI display has an insufficientnumber of characters for the full length descriptor. The alarm function and control loop data (Fig. 10c)will impact the Sequence Matrix inputs. Note that these three sections of Figure 10 will typically appearleft to right in a spreadsheet and not as three separate items as shown in this document. This will moreclearly show the relationship between the various sets of information. Obviously in this format the firstthree columns need not be repeated.

    Figure 11a illustrates the software interlock matrix for Unit R-101, which provides the following processfunctionality based on the P&ID:

    (a) If the liquid level is too low interlocks UC-102 and UC-104 will shut off the mixer and pump.(b) Interlock UC-104 will prevent the drain pump from operating if the drain valve is closed.(c) Interlock UC-003 shuts down the charging control module when the desired charge quantity has

    been satisfied.

    The Manual Reset capability for each interlock in this example is provided by de-energizing theassociated Hand Switch that is normally used to manually change valve position or motor condition. Inthis way the Hand Switch outputs will not immediately reactivate the interlocked device when the initiatingcondition clears. Any additional interlocks would be set up the same way. Definitions for the hazard andsafety levels are based on the example shown in Figure 6.

    Figure 11b illustrates the software interlock matrix for the exclusive use common Equipment Module EM-1which provides the following functionality based on standard operating practices:

    (a) Reinforce the hardwired charge valve interlocks shown on the P&ID by de-energizing theassociated Hand Switch when a reactor level exceeds its safe limit, thereby requiring operatorintervention (Manual Reset) for charging to resume after the condition clears.

    (b) Additional interlocks help to assure integrity of the charge path and measurement of the chargedquantity.

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    CM TAG LOCATION P&ID POINT TYPE ** DEVICE TYPE SIGNAL TYPE I/O TAGS

    XV-001R-101 P-101 VLV-FC BALL VALVE 24 VDC

    ZSC, ZSO,

    XS

    XV-002 R-102 P-101 VLV-FC BALL VALVE 24 VDCZSC, ZSO,

    XS

    HS-003 P-003 P-101 MOTOR PUMP 120 VAC XI, XS

    CORIOLIS / FTFC-003 P-003 P-101 LOOP

    GLOBE VALVE4-20 MA FT, FV

    FQ-003 P-003 P-101 ACCUM - software FC-003.PV

    ZIC-004A P-003 P-101 VLV-1 BALL VALVE 24 VDC ZSC

    ZIC-004B P-003 P-101 VLV-1 BALL VALVE 24 VDC ZSC

    ZIC-004C P-003 P-101 VLV-1 BALL VALVE 24 VDC ZSC

    HS-004 P-003 P-101 HS-004 - software ZIC-004A,B,

    LI-101 R-101 P-101 AI RADAR 4-20 MA LT

    HS-102 AG-102 P-101 MOTOR AGITATOR 120 VAC XI, XS

    LAHH-103 R-101 P-101 ALARM-1 CONDUCTIVITY 24 VDC LSH

    HS-104 P-104 P-101 MOTOR PUMP 120 VAC XI, XS

    XV-105 R-101 P-101 VLV-FC PLUG VALVE 24 VDCZSC, ZSO,

    XS

    PT RTD / TT(chr)TC-106 R-101 P-101 LOOP

    GLOBE VALVE4-20 MA TT, TV

    * I/O counts to be replaced by addresses upon system selection and I/O assignment

    ** Functionality defined by Control Module class definition matrix (Fig. 10d)

    Figure 10a Database I/O information

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    SCALECM TAGLOCATION P&ID

    LOW HIGH

    ENG.

    UNITSDESCRIPTOR

    XV-001 R-101 P-101 REACTOR INLET VALVE

    XV-002 R-102 P-101 REACTOR INLET VALVE HS-003 P-003 P-101 FILL PUMP MOTOR

    FC-003 P-003 P-101 0 1000 LB/MIN FEED FLOW CONTROLLER

    FQ-003 P-003 P-101 0 30000 LBS FEED TOTALIZING SWITCH

    ZIC-004A P-003 P-101 FEED MANIFOLD VALVE A

    ZIC-004B P-003 P-101 FEED MANIFOLD VALVE B

    ZIC-004C P-003 P-101 FEED MANIFOLD VALVE C

    HS-004 P-003 P-101 FILL SOURCE SELECTOR

    LI-101 R-101 P-101 0 100 % REACTOR LEVEL INDICATOR

    HS-102 AG-102 P-101 REACTOR AGITATOR

    LAHH-103 R-101 P-101 REACTOR HIHI LEVEL ALARM

    HS-104 P-104 P-101 DRAIN PUMP MOTOR

    XV-105 R-101 P-101 REACTOR OUTLET VALVE

    TC-106 R-101 P-101 70 250 DEGREE C TEMERATURE CONTROLLER

    Figure 10b Database HMI information

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    ALARM FUNCTIONS COCM TAGLOCATION P&ID

    TYPE SP PRIORITY

    OUTPUTDIRECTION

    TYPE AL

    XV-001 R-101 P-101 FB_ERR 10 SEC MED DIRECT .

    XV-002 R-201 P-101 FB_ERR 10 SEC MED DIRECT

    HS-003 P-003 P-101 FB_ERR 3 SEC MED DIRECT

    FC-003 P-003 P-101 . DIRECT M/A

    FQ-003 P-003 P-101 FQSH RECIPE LOG ONLY

    ZIC-004A P-003 P-101 STATE * ** MED

    ZIC-004B P-003 P-101 STATE * ** MED

    ZIC-004C P-003 P-101 STATE * ** MED

    HS-004 P-003 P-101

    LI-101 R-101 P-101LAHLSLLSLL

    85%10%3%

    MEDLOG ONLYLOG ONLY

    . .

    HS-102 AG-102 P-101 FB_ERR 3 SEC MED DIRECT .

    LAHH-103 R-101 P-101 STATE HIGH . .

    HS-104 P-104 P-101 FB_ERR 3 SEC MED DIRECT .

    XV-105 R-101 P-101 FB_ERR 10 SEC MED DIRECT .

    TC-106 R-101 P-101 TAHHTAH

    200 CRECIPE

    HIGHMED

    DIRECT M/A

    * Enabled/disabled by HS-004 according to commanded position

    ** Set by HS-004 according to commanded position

    Figure 10c Database operating information

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    INPUTS CORRCLASSFEATURES

    INPUT STATE INPUT 1 INPUT 2 INPUT 3 COMMANDED ST

    I/O - ZIC ZSO -

    OPEN OFF ON OPEN

    CLOSED ON OFF CLOSED

    MOVING OFF OFFSTATE NAMES

    INVALID ON ON

    ALARM TYPE FB_ERR ALARM IF INPUT STATE DOES NOT TRACK OUTPUT STATEINTERLOCK FORCE CLOSE

    VLV-FC

    TRIP LOGICFB_ERR COMMAND CLOS

    I/O - XI -

    RUN ON RUN STATE NAMES

    STOP OFF STOP

    ALARM TYPE FB_ERR ALARM IF INPUT STATE DOES NOT TRACK OUTPUT STATE

    INTERLOCK FORCE STOP

    MOTOR

    TRIP LOGICFB_ERR COMMAND STO

    I/O - LSHH

    LAHH OFFSTATE NAMES

    NORMAL ONALARM-1

    ALARM TYPE STATE ALARM IF LSHH = OFF

    I/O - ZIC

    OPEN OFFSTATE NAMESCLOSED ON

    VLV-1

    ALARM TYPE STATE ALARM IF ZSC = OFF

    I/O - ZIC-004A ZIC-004B ZIC-004C

    OPEN_A OFF ON ON

    OPEN_B ON OFF ON

    OPEN_C ON ON OFF

    CLOSED ON ON ON

    STATE NAMES

    MISALIGNED ANY OTHER COMBINATION

    ENABLE ZIC-004A/B/C ALARMS WHEN HS-003 OUTPUT (DESIRED) STATE IS NOT CLOSED;

    ALARM STATES OF ZIC-004A/B/C ACCORDING TO HS-004 OUTPUT AS FOLLOWS:

    ZIC ON ZIC OFF ZIC OFF OPEN_A

    ZIC OFF ZIC ON ZIC OFF OPEN_B

    ZIC OFF ZIC OFF ZIC ON OPEN_C

    HS-004

    LOGIC FOR

    ENABLING

    EXTERNAL

    ALARMS

    ZIC ON ZIC ON ZIC ON CLOSED

    * Identified as Point Type in Figure 10a ** Actual timing individually adjustable for each insta

    Figure 10d Control module class definition

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    INITIATING DEVICES (FAULT)CONTROL DEVICES

    (ACTION)ID NUMBER

    SETPOINTS LOGIC

    HAZARD

    LEVEL

    SAFETY

    INTEGRITY

    LEVEL

    OPERATING MODE

    UC-003

    {HS-004 CMD = CLOSED *}

    OR {HS-004 INPUT = MISALIGNED *} OR

    {FQ-003 > RECIPE SP

    (FQSH-003 ON)}

    STOP P-003

    (XS-003 OFF)LOW 1 MANUAL RESET

    UC-102LI-101 < 10%

    (LAL-101 ON)

    STOP AG-102

    (XS-102 OFF)LOW 1 MANUAL RESET

    UC-104

    {XV-101 CLOSED

    (ZIC-101 ON)} OR

    {P-104 RUNNING (XS-104 FB ON) FOR

    60 SEC WHILE LI-101 < 3% (LALL-101

    ON)}

    STOP P-104

    (XS-104 OFF)LOW 1 MANUAL RESET

    * Not shown on P&ID

    Figure 11a Software interlock matrix for Unit R-101

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    INITIATING DEVICES (FAULT)CONTROL DEVICES

    (ACTION)

    ID NUMBER

    SETPOINTS LOGIC

    OPERATING

    MODE

    *

    {LAHH-103 IN ALARM

    (ALSO HARDWIRED***)} OR

    {R01.BATCHID EM1.BATCHID **} OR

    {XV-002 OPEN (ZSC-002 OFF)} OR

    {HS-004 MISALIGNED (INPUT STATE)}

    CLOSE XV-001

    (HS-001 OFF)

    MANUAL

    RESET

    PREVE

    CO

    INTEGR

    PREVEN

    *

    {LAHH-203**** IN ALARM

    (ALSO HARDWIRED***)} OR

    {R02.BATCHID EM1.BATCHID **} OR

    {XV-002 OPEN (ZSC-002 OFF)} OR

    {HS-004 MISALIGNED (INPUT STATE)}

    CLOSE XV-002

    (HS-002 OFF)

    MANUALRESET

    PREVENT

    CO

    INTEGR

    PREVEN

    *

    {XV-001 FB_ERR OR XV-002 FB_ERR

    (ALARM STATES)} OR

    {XV-001 CLOSED AND XV-002 CLOSED (COMMAND

    STATES)} OR

    {HS-004 CLOSED (INPUT STATE)}

    STOP P-003

    (HS-003 OFF)

    MANUAL

    RESET

    INT

    PRE

    D

    PREVE

    * P-003 RUNNING (XI-003 ON)

    START FQC-003

    INTEGRATION (FQ-003

    ACCUMULATOR)

    MANUAL

    RESETINTEGR

    * Not shown on P&ID** BATCHIDs allocated by recipe after confirming EM or unit availability

    *** SIL satisfied by hardwired protection; independent software layer provided for proper HS operation.**** LAHH-203 specified separately in R-201 database matrix

    Figure 11b Software interlock matrix for Equipment Module EM-

    ANSI

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    The Sequence Matrix (Figures 12a, b, c) for this relatively simple example can quickly become veryinvolved because of the number of potential interactions among the control entities. To avoidoverwhelming complexity, it is imperative to efficiently modularize the sequencing requirements byseparating low-level and highly reusable equipment-centric sequences from high-level product-centricrequirements. For notational simplicity, the abbreviations OP, SP, and PV are used to denote the output,setpoint, and measured value, respectively, for each loop.

    The Fill and Dump phases in Figure 12a show three steps with their sequence of operation tocomplete the phase. For the Fill phase, the agitator must be stopped, then the outlet valve must beclosed; finally, the fill module will operate to permit entry of material. The fill module will not be instructedto operate by the control system until both of the other steps have been completed.

    Interruption of a particular phase can result from multiple causes as shown in Figure 12b. Each cause willresult in an appropriate alarm message at the operator console. Recovery from this interruption will occuras shown if the control system is in auto mode. Otherwise, operator intervention will be required toresume operations.

    The Recipe Matrix may have very specific values for each recipe parameter or have a range as shownin Figure 12c. If ranges are included, the security level required to enter or change a particular valuemust be shown in the Parameter Entered By column. The recipe to be used for each batch is selectedfrom the options in Figure 12c.

    The batch sequence matrix must also contain logic to request allocation of equipment module EM-1 to thebatch and, upon acceptance by EM-1, to set its parameters and initiate its phase logic. EM-1 continuouslycompares its batch assignment with those downstream of XV-001 and XV-002, to determine which one (ifeither) to enable and which to force closed. The recipe-controlled HS-004 setpoint determines the properZIC-004A/B/C permissives to operate the feed pump and alarms if any valve is opened erroneously.

    Figures 12a, b, c define the procedural control requirements for Unit R-101 at a suitable level of detail fora User Requirement Specification (URS). The full level of phase specification detail required for aFunctional Requirement Specification (FRS) is illustrated in Figure 12d for the exclusive use commonEquipment Modules FILL_R101 phase. The top section shows the final setpoints and initial values for the

    control modules plus other reference values used during this phase. The bottom section of Figure 12dshows the detailed actions and end conditions for each of the steps referred to above. The text commentgives a good description of the purpose for each step. The step sequence diagram may be included ifnecessary to illustrate parallel execution paths. The FRS information for R-101 would include a similarlevel of detail.

    It is generally easier to keep all the information clear by stacking the normal, hold, and recipe matrixelements on top of one another in a spreadsheet. This is shown on the matrix for the equipment module(Figure 12d). In certain instances, there may be more than one condition, which would cause a phase toend or a Hold Condition to occur. To clearly show this, split the column under the particular phase andenter both conditions.

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    OPERATIONS PREPARATION REACTION TRANSFER

    PHASES INITIAL FILL HEAT CURE DUMP

    PHASE REF. NO. (1) (2) (3) (4) (5)

    CM TAG DESCRIPTION

    XV-105 OUTLET VALVE CLOSED CLOSE (2) CLOSE CLOSE OPEN (2) CLO

    HS-102 AGITATOR STOPPED STOP (1) RUN RUN STOP (1)

    HS-104 DRAIN PUMP STOPPED STOP (1) STOP STOP RUN (3) STO

    DISCRETE

    CONTROL

    MODULES

    TC-106 BATCH TEMP.RAMP SP: AT 2

    DEG/MINANALOG

    CONTROLMODULES FQ-003 FILL AMOUNT RESET TOTAL=0

    ACQUIRED

    EQUIPMENTMODULE

    PHASES &PARAMETERS

    EM1.FILL_R101 N/A

    RUN (3);

    EM1.BATCHID =

    R101.BATCHID;

    EM1.RM_SRC =

    XV-002;

    EM1.FQ_TOT.TAR =

    R101.RP3.TAR

    N/A N/A N/A

    EM

    R

    E

    EM1

    END OF PHASE CONDITIONSIF LI-101 < 1%

    AND OPERATORSTART BATCH

    PV OF FQ-003= RP3(SEE RECIPE

    MATRIX)

    PV OF TC-106= RP1 (SEE

    RECIPEMATRIX)

    WAIT TIME=RP2HOURS (SEE

    RECIPEMATRIX)

    LI-101=

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    OPERATIONS PREPARATION REACTION END

    PHASES INITIAL FILL HEAT CURE DUMP

    PHASE REF. NO. (1) (2) (3) (4) (5)

    CM TAG

    XV-001

    XV-105 OPEN OPEN

    HS-102 STOP

    DISCRETE

    CONTROL

    MODULES

    HS-104

    TC-106 IF >140 C IF >140 C

    FQ-003 IF > RP3

    ANALOG

    CONTROL

    MODULES LI-101 > 1 % IF > 5%

    ACQUIRED

    EQUIPMENTMODULES

    EM-1 FILL_R101.HOLD

    I

    N

    I

    T

    I

    A

    T

    I

    N

    G

    C

    O

    N

    D

    I

    T

    I

    O

    N\

    S

    ELAPSED TIME IF >30 min IF >2 hr IF >30 m

    HOLD ACTIONS

    DO NOTPROCEED TO

    FILLINGPHASE

    CLOSE XV-001

    SET TC-106

    = 60C

    SET TC-106

    = 60C

    CLOSE XV-

    OPERATOR MESSAGESEMPTY

    REACTORCHECK XV-105

    CHECK AG-102

    H

    O

    L

    D

    S

    E

    Q

    U

    E

    N

    C

    E

    RECOVERYRESTART

    PHASE RESUME PHASEGO TO SHUT-

    DOWNRESTART

    PHASERESUMEPHASE

    Figure 12b Hold sequence matr ix for Unit R-101

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    RECIPE RECIPE PRAMETER INITIAL FILL HEAT CURE

    # PARAMETERS(RP) ENTERED BY (1) (2) (3) (4)

    FQ-003 (RP3) PROGRAM 1000 L

    CURE PHASE TIME (RP2) OPERATOR 1 HR < Y < 2 HA

    TC-106 (RP1) SUPERVISOR 50C< X

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    39 ANSI/ISA5.06.012007

    Copyright 2007 ISA. All rights reserved.

    PHASE EM1.FILL_ R101

    PARAM. SCOPETYPE /RANGE

    IDENTIFIERCORRESPONDINGACTUAL VALUE

    TEXT EM1.BATCHID

    HS004_ENUM EM1.RM_SRCRECIPE-WRITTEN

    1000-5000 EM1.FQ_TOT FQ-003.TOTAL IN STEP 8

    TIME/DATE START & END TIMESRECORDED AT PHASE

    START & ENDREPORT *

    TEXT OPER_ID RECORDED IN STEP 8

    0-100 EM1.VLV_POS 50

    0-150 EM1.FLOW_SP 120

    0-500 EM1.PRESET 200

    0-50 EM1.TRICKLE 30

    PARA

    METERS

    INTERNAL

    TEXT EM1.MSG_TEXT " "

    STEP# DEVICE ACTIONS END CONDITION

    XV-002 CLOSED1

    FQ-003 RESET IF HS-001 OFFZSC-002 ON

    HS-004 EM1.RM_SRC

    2 OPERATORMESSAGE

    "PREPARE FEED SOURCE RM_SRC AND ALIGN MANUAL

    VALVES"

    HS-004.INPUT STATE =COMMANDED STATE

    XV-001 OPEN3

    FQ-003 SP=FQ_TOT.TAR; STARTZSC-001 OFF

    FC-003 MANUAL; OUTPUT = VLV_POS4HS-003 RUN

    XI-003 ON FOR 15 SEC

    FC-003 AUTO; SP = FLOW_SP5 OPERATOR

    MESSAGEIF STEP TIME>60 MINS: "CHARGETIME EXCEEDED: CHECK FLOW"

    FQ-003.TOTAL >FQ-003.SP - PRESET

    FIC-003 AUTO; SP = TRICKLE

    6 OPERATORMESSAGE

    IF STEP TIME>5 MINS: "CHARGETIME EXCEEDED: CHECK FLOW"

    FQ-003.TOTAL >FQ-003.SP

    HS-003 STOP7

    FC-003 OUTPUT = 0WAIT 10 SEC

    XV-001 CLOSED

    HS-004 CLOSED

    FQ-003 STOP; FQ_TOT.ACT = TOTAL

    NORMALSEQUENC

    E

    8

    OPERATOR

    MESSAGE

    "CONFIRM CHARGE PROPERLY

    COMPLETED"

    OPER_ID RECORDED WITHMESSAGE CONFIRMATION

    DEVICE CONDITION (ACTIVE STEPS) MSG_TEXT VALUE

    XV-002 FB_ERR AND HS-002 OFF (1-6) "CHECK XV-002 AND"

    HS-004 MISALIGNED OR CLOSED (3-6)"CHECK RM MANIFOLD

    AND"

    FB_ERR (3) "CHECK XV-001 AND"XV-001

    HS-001 OFF (4-6) "CHECK XV-001 AND"

    FB_ERR (4) "CHECK HS-003 AND"HS-003

    XI-003 OFF (5-6) "CHECK HS-003 AND"

    INITIATINGCONDITIONS

    HMI OPERATOR INITIATED (1-6) "OPERATOR INITIATED -"

    STEP# DEVICE ACTIONS END CONDITION

    HS-003 STOPH1

    FC-003 MANUAL; OUTPUT = 0WAIT 10 SEC

    XV-001 CLOSED

    XV-002 CLOSED

    HS-004 CLOSED

    FQ-003 STOP

    HOLD

    SEQUENCE

    H2

    OPERATORMESSAGE

    "HOLDING FILL: "; MSG_TEXT; "CONFIRM WHEN OK TO RESUME"

    OPERATOR CONFIRMS

    MESSAGE

    * BESIDES ACTUAL VALUES CORRESPONDING TO EACH RECIPE-WRITTEN VARIABLE

    Figure 12d Equipment module sequence matrix for EM-1 phase FILL_R101

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    ANSI/ISA5.06.012007 40

    Copyright 2007 ISA. All rights reserved.

    The graphical elements shown in Figure 13a are typical of those available from ISA-5.5-1985, GraphicSymbols for Process Displays. These can generally be added to a display and configured as required tobe active elements. The two status displays (Figures 13b & 13c) will quickly show the operator the currentcondition of each interlock and the progress through a recipe. These are also valuable for troubleshootingwhen it becomes necessary.

    Control Valve

    Motor

    M

    M/AI/B

    XM-601

    M/A

    I/B C/O

    XV-501

    Manual / Auto

    Manual / Auto

    Interlock/Bypass

    Interlock/Bypass

    Show only on failure

    Green Red Yellow Blinking

    Yellow

    Open Close Trav el Failure

    Green Red Blinking

    Yellow

    Run Stop FailureS/R

    Figure 13a Graphic elements

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    41 ANSI/ISA5.06.012007

    Copyright 2007 ISA. All rights reserved.

    I #

    1

    3

    2

    4

    5

    6

    7

    Ag itator

    Ag-1

    Outlet

    pump

    XM-1

    Steam

    Valve

    TV-1Initi ating Devices

    Low Rx level ( 200C)

    ARAR ARAR

    RR

    AR = AUTOMATIC RESET

    R= MANUAL RESETCommon larm

    Figure 13b Interlock status display

    Operator Message

    Initial

    Fill

    HeatCureDump

    Shutdown

    Parameter Actual Target

    Recipe # A

    Modes of operation

    Automatic

    Start Phase

    Stop Phase

    Phases:

    Phase Progress

    Start Sequence

    Stop Sequence

    Catalyst Volume 450 Gal. 500 Gal.

    Operation: Reaction

    Common Alarm

    Manual

    Figure 13c Sequence status display

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    ANSI/ISA5.06.012007 42

    Copyright 2007 ISA. All rights reserved.

    Most systems available today have these and many other standard elements built in and ready to useafter minimal configuration. Special elements can also be created as needed using CAD software. Thisshould seldom be needed given the large library of control face plates, alarm lists, interlockannunciations, etc.

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    43 ANSI/ISA5.06.012007

    Copyright 2007 ISA. All rights reserved.

    Annex B (informative) Applicat ion Example 2: Continuous Dist il lation Column

    The following distillation example illustrates the application of the methodology to a continuous process.The P&ID for this example is shown in Figure 14. The distillation column feed comes from Tank T-101through an economizer. The reflux is on flow control and the reflux drum level controls the distillate flow.

    The distillation column pressure is controlled by a vacuum pump. Obviously, many other control schemesare possible and necessary for specific processes. This scheme was chosen only to provide informationfor this example. Only basic interlocks are shown here. Additional instrumentation and interlocks would benecessary to provide the level of personnel and process safety required by most processes today.

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    DISTILLATIONCOLUMN

    C-104

    CONDENSERH-106

    REFLUX

    DRUM

    T-107

    FEED TANKT-101

    FEED PUMPP-102

    REFLUX PUMPP-110

    BOTTOMS PUMPP-111

    FEEDECONOMIZER

    H-103

    T

    CHILLEDRET

    CHILLED

    SUP

    COOLING WATERSUPPLY

    COOLING WATERRETURN

    HIGH PRESSURE

    STEAM

    STEAM

    CONDENSATE

    LT107

    HS

    110

    FSL106

    TV

    107

    TC

    107

    TT

    107

    PT106

    PC106

    LV104

    LT104

    FV107 FC

    107

    FT107

    HS

    111

    FV101

    FT101

    FC101

    LT101

    LI

    101

    HS102

    FAL

    106PAHPAL

    LC

    LAL107

    TT104

    FAL101

    101

    LAL

    CDISTIL

    D

    VENT CONDENSERH-108

    LAH

    107

    UC110

    TV

    104

    LC104

    LAL104

    TC104

    TAHTAL

    TT106

    TI

    106TO

    UC-104

    FROM

    FAL-106

    UC

    104

    UC

    102

    UC

    111

    Figure 14 Continuous Distillation Column P&ID

    Copyright2007ISA.Allrightsreserved.

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    45 ANSI/ISA5.06.012007

    Copyright 2007 ISA. All rights reserved.

    The database (Figures 15a, b, c) gives the information for all devices in the P&ID (Figure 14). The digitalcontrol module classes identified in the Point Type column (Figure 15a) are functionally defined by therespective class details shown in Figure 10d (see previous example).

    I/O address information (Figure 15a) initially will show only the types and number of connections from thiscontrol module to the system. When the actual plant layout is known, these can be replaced by columnsshowing the cabinet and cable connections, software logical connections, and/or software address for theparticular process system. This requires some knowledge of the new or existing layouts.

    The HMI information for scale and engineering units (Figure 15b) will come from process information andpossibly equipment design limits. The keyword is necessary only if the HMI display has an insufficientnumber of characters for the full length descriptor.

    The alarm function and control loop data (Figure 15c) will impact the Sequence Matrix inputs. This isset up and prepared using the same methodology as for the batch example above.

    Figure 16 illustrates the software interlock matrix for Unit C-104, which provides the followingprocess functionality based on the P&ID:

    (a) Interlock UC-102 turns off the column feed pump (P-102) when the feed tank (T-101) leveldrops below 2500 liters. (Turning off this pump will eventually activate UC-104 and UC-111,shutting down the column steam supply and bottoms pump.)

    (b) Interlock UC-104 closes the reboiler steam valve (TV-104) if the column level drops belowthe 5% value or if the condenser cooling water flow slows (FAL-106).

    (c) Interlock UC-110 turns off the reflux pump (P-110) when the reflux drum level (LIC-107)reaches 10%.

    (d) Interlock UC-111 turns off the bottoms pump (P-111) if the column level drops below the 5%value.

    The Manual Reset capability for each interlock in this example is provided by de-energizing theassociated Hand Switch that is normally used to manually change valve position or motor condition. Inthis way, the Hand Switch outputs will not immediately reactivate the interlocked device when the

    initiating condition clears. Any additional interlocks, including those to meet operational requirements andstandard operating practice, would be set up the same way. Definitions for the hazard and safety levelsare based on the example shown in Figure 6.

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    CM TAG LOCATION P&IDPOINT TYPE

    **DEVICE TYPE SIGNAL TYPE I/O TAG

    FC-101 T-101 P-104 LOOPORIFICE / PDT();

    GLOBE VALVE4-20 MA FT, FV

    LI-101 T-101 P-104 AI PDT 4-20 MA LT

    HS-102 P-103 P-104 MOTOR PUMP 120 VAC XI, XS

    LC-104 C-104 P-104 LOOPPDT;

    GLOBE VALVEFIELDBUS LT,LV

    TC-104 C-104 P-104 LOOPPT RTD / TT(chr);

    GLOBE VALVEFIELDBUS TT, TV

    FAL-106 H-106 P-104 ALARM-1 FSL 24 VDC FSL

    PC-106 C-104 P-104 LOOPPT(abs);

    GLOBE VALVEFIELDBUS PT, PV

    TI-106 C-104 P-104 AI PT RTD / TT(chr) 4-20 MA TT

    FC-107 T-107 P-104 LOOP PDT;GLOBE VALVE

    4-20 MA FT, FV

    LC-107 T-107 P-104 LOOPPDT;

    GLOBE VALVE4-20 MA LT, LV

    TC-107 H-106 P-104 LOOPPT RTD / TT(char);

    GLOBE VALVE4-20 MA TT, TV

    HS-109 P-109 P-104 MOTOR PUMP 120 VAC XI, XS

    HS-110 P-110 P-104 MOTOR PUMP 120 VAC XI, XS

    HS-111 P-111 P-104 MOTOR PUMP 120 VAC XI, XS

    * I/O counts to be replaced by addresses upon system selection and I/O assignment

    ** Functionality defined by Control Module class definition matrix (Fig. 10d)

    Figure 15a Database I/O information

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    SCALECM TAGLOCATION P&ID

    LOW HIGH

    ENG.

    UNITSDESCRIPTOR

    FC-101 T-101 P-104 10 100 LPM COLUMN FEED RATE

    LI-101 T-101 P-104 0 50000 LITER FEED TANK LEVEL

    HS-102 P-103 P-104 FEED PUMP

    LC-104 C-104 P-104 0 100 % COLUMN BOTTOM LEVEL

    TC-104 C-104 P-104 0 250 Deg. C BOTTOMS TEMPERATURE CONTROL

    FAL-106 H-106 P-104 CONDENSER LOW WATER FLOW

    PC-106 C-104 P-104 0 800 mmHg abs COLUMN OVERHEAD PRESS

    TI-106 C-104 P-104 0 250 Deg. C COLUMN OVERHEAD TEMP

    FC-107 T-107 P-104 0 200 LPM REFLUX FLOW RATE

    LC-107 T-107 P-104 0 100 % REFLUX DRUM LEVEL

    TC-107 H-106 P-104 0 250 Deg. C CONDENSATE TEMP

    HS-109 P-109 P-104 COLUMN VACUUM PUMP

    HS-110 P-110 P-104 REFLUX PUMP

    HS-111 P-111 P-104 COLUMN BOTTOMS PUMP

    Figure 15b Database HMI information

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    ALARM FUNCTIONS CONTROLCM TAGLOCATION P&ID

    TYPE SP PRIORITY

    OUTPUT

    DIRECTIONTYPE ALGORIT

    FC-101 T-101P-

    104FAL 15 HIGH DIRECT M/A/SUP P,I,D

    LI-101 T-101P-

    104

    LAH

    LAL

    40000

    2500

    HIGH

    MED

    HS-102 P-103P-

    104FB_ERR

    3

    SECMED DIRECT M/A

    LC-104 C-104P-

    104LAL 10 MED DIRECT M/A/SUP P,I,D

    TC-104 C-104P-

    104

    TAH

    TAL

    135

    115

    MED

    MEDDIRECT M/A/SUP P,I,D

    FAL-106 H-106P-

    104STATE HIGH

    PC-106 C-104P-

    104

    PAH

    PAL

    120

    80

    MED

    MEDDIRECT M/A P,I,D

    TI-106 C-104 P-104

    FC-107 T-107P-

    104DIRECT M/A P,I,D

    LC-107 T-107P-

    104LAL 10 MED DIRECT M/A/SUP P,I,D

    TC-107 H-106P-

    104REVERSE M/A/SUP P,I,D

    HS-109 P-109P-

    104FB_ERR

    3

    SECMED DIRECT M/A

    HS-110 P-110P-

    104FB_ERR

    3

    SECMED DIRECT M/A

    HS-111 P-111P-

    104FB_ERR

    3

    SECMED DIRECT M/A

    Figure 15c Database operating information

    Copyright2

    007ISA.Allrightsreserved.

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    INITIATING DEVICES

    (FAULT)CONTROL DEVICES (ACTION)

    ID NUMBER

    SETPOINTS LOGIC

    HAZARD

    LEVEL

    SAFETY

    INTEGRITY

    LEVEL

    OPERATIN

    UC-102LI-101 < 2500 L

    (LAL-101 ON)

    STOP P-102

    (HS-102 OFF)LOW 1 MANUAL

    UC-104

    {FAL-106 IN ALARM

    (ALSO HARDWIRED)} OR

    {LC-104 < 5%

    (LAL-104 ON)}

    CLOSE TV-104

    (TIC-104 OUTPUT = 0)MEDIUM 2 MANUAL

    UC-110LC-107 < 10%

    (LAL-107 ON)

    STOP P-110

    (HS-110 OFF)LOW 1 MANUAL

    UC-111 LC-104 < 5%(LAL-104 ON)

    STOP P-111(HS-111 OFF)

    LOW 1 MANUAL

    Figure 16 Interlock matrix

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    ANSI/ISA5.06.012007 50

    Copyright 2007 ISA. All rights reserved.

    A continuous process will normally have fewer phases than for batch, if any at all. The sequence matrixfor this example is shown in User Requirement Specification (URS) format in Figures 17a and 17b. Thesequence of phase commands to control modules is identified by the adjacent numbering. Unlessotherwise noted, each step remains active until the corresponding feedback signal confirms the specifiedaction(s). If no sequence numbering exists, the phase comprises a single step in which all specifiedactions must be confirmed before the system can move to the next phase. All steps must be completedand the End Of Phase Conditions satisfied before transitioning to a subsequent phase. For the Drainphase (4), all of the actions with (1) following them are executed as soon as the control system moves tothis phase. The other actions then follow in order, pending confirmation of each.

    The steps for the Startup phase (2) become very complex for this system. There are actually threeparallel paths occurring here. This is best shown in the step sequence diagram at the bottom of Figure17c. The number sequence shown here can often only be developed after something similar to the stepsequence diagram is developed. Path A sets up the reboiler and bottoms pump; path B starts up theoverhead system; while path C sets up the feed system. These can proceed independently until all threesystems are operating. Only after all three pathways are fully satisfied will the system transition to theDistill phase.

    The full level of phase specification detail required for a Functional Requirement Specification (FRS) isillustrated for the Startup phase in Figure 17c. The top section shows the final setpoints and initial values

    for the control modules plus other reference values used during this phase. The step sequence diagramshows the parallel paths used to begin operations for each part of this unit. The bottom section of Figure17c shows the detailed actions and end conditions for each of the steps referred to above. The textcomment gives a good description of the purpose for each step.

    The detailed information for the other phases would have a similar appearance. Other formats can alsobe used to show this information, including sequential function charts, ladder diagrams, and textnarratives.

    No recipe matrix is included here, as the operating values for a single set of conditions can be entereddirectly into the Normal Sequence Matrix. Once up and running, this process will typically remain in theDistill phase for an extended period of time. The Preparation and End phases are very similar for thebatch and continuous processes.

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    OPERATIONS PREPARATION RUN

    PHASES

    CONTROL DEVICES

    CM TAG KEYWORD

    INITIAL

    (1)

    START-UP

    (2)

    DISTILL

    (3)

    DRAIN

    (4)

    HS-102 FEED PMP STOPPEDRUN (4C);

    STOP (6C)RUN STOP (1

    HS-109 VACM PMP STOPPED RUN (2) RUN STOP (1

    HS-110 REFL PMP STOPPED RUN (5B) RUN STOP (3A

    DISCRETECONTROL

    MODULES

    HS-111 BOTM PMP STOPPED RUN (5A) RUN

    STOP (1

    RUN (3B

    STOP (5

    FC-101 FEED FLOOP = 30 (4C);

    SP = 75 (5C)OP = 0 (1

    LC-104 BOTM LVLOP = 20 (5A);

    SP = 50 (6A)

    OP = 0 (1

    WAIT UNT

    PV < 10 (

    TC-104 BOTM TMPOP LIC104 (3A);

    SP = 125 (4A)OP = 0 (1

    TC-107 COND TMPOP = 100 (1);

    SP < 40 (4B)OP = 0 (5

    PC-106 OVHD PRS SP = 85 (2) OP = 0 (1

    LC-107 RFLX LVL SP > 20 (7B) OP = 0 (1

    ANALOG

    CONTROL

    MODULES

    FC-107 RFLX FLOOP = 20 (5B);

    SP = 35 (6B)

    OP = 100 (

    WAIT UNT

    PV < 10 (2

    OP = 0 (3

    END OF PHASE

    CONDITIONSLI-101 > 40,000

    ALL PV TARGETS

    SATISFIED

    OPERATOR INITIATED OR

    LI-101 < 1000

    ALLOWABLE

    PHASE

    TRANSITIONS

    2 3 2, 5 5

    OPERATOR

    MESSAGES

    READY TO

    START

    REDIRECT C

    BOTMS TO BL

    CONFIRM(

    Figure 17a Normal sequence matr ix for Unit C-104 (URS format)

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    OPERATIONS PREPARATION RUN

    PHASES

    CONTROL DEVICES

    CM TAGKEYWORD

    INITIAL

    (1)

    START-UP

    (2)

    DISTILL

    (3)

    DRAIN

    (4)

    SHU

    HS-102 FEED PMP STOP

    HS-109 VACM PMP STOP

    HS-110 REFL PMP STOP

    DISCRETE

    MODULES

    HS-111 BOTM PMP STOP

    LI-101 FEED LVL IF PV < 15K IF PV > 2000

    FC-101 FEED FLO IF PV < 20

    LC-104 BOTM LVL IF PV < 5 IF PV > 1

    TC-104 BOTM TMP 120 > PV > 150

    TC-107 COND TMP 20 > PV > 40

    PC-106 OVHD PRS 75 > PV > 95 IF PV < 125

    LC-107 RFLX LVL

    ANALOG

    MODULES

    FC-107 RFLX FLO 25 > PV > 45 IF PV > 0

    I

    N

    I

    T

    I

    A

    T

    I

    N

    G

    C

    O

    N

    D

    I

    T

    I

    O

    N

    S

    ELAPSED TIME

    HOLD ACTIONSSTOP HS-102,

    HS-111

    OPERATOR MESSAGESPROBLEMS

    WITH SYSTEMDRAIN

    RECOVERYGO TO

    START-UP

    RESUME

    Figure 17b Hold sequence matr ix for Unit C-104 (URS format)

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    PHASE C104.STARTUP

    PARAM.

    SCOPE

    TYPE /

    RANGEIDENTIFIER CORRESPONDING ACTUAL VALUE

    0-250 .CW_SP 40

    0-400 .PC_SP 85

    0-250 .BTM_T_SP 125

    0-100 .BTM_L_SP 50

    0-200 .RFLX_SP 150

    0-100 .OHD_L_SP 50

    INTERNAL

    (FINAL SP)

    10-100 .FEED_SP 75

    0-100 .CW_INIT 100

    0-100 .BTM_L_INIT 20

    0-100 .RFLX_INIT 20

    INTERNAL

    (INIT VAL)

    0-100 .FEED_INIT 30

    0-150 .PIC_HI 95

    0-120 .BTM_T_TIMSP 60

    0-120 .BTM_L_TIMSP 30

    0-100 .BTM_L_LOREF 20

    0-100 .BTM_L_LOPB 10

    0-100 .BTM_L_HIREF 80

    0-100 .BTM_L_HIPB 20

    0-100 .BTM_L_HIHI 90

    0-100 .BTM_L_DEV 5

    0-250 .OVHD_T_INIT 70

    0-250 .OVHD_T_NORM 500-100 .OVHD_L_LOREF 20

    0-100 .OVHD_L_LOPB 10

    10-100 .FEED_LO 15

    PARAMETERS

    INTERNAL

    (REF VAL)

    10-100 .FEED_SP_MIN 30

    N

    ORMALSEQUENCE

    STEP

    SEQUENCE

    DIAGRAM

    Figure 17c Sequence matrix for C-104 Startup phase in FRS format (continue

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    55 ANSI/ISA5.06.012007

    Copyright 2007 ISA. All rights reserved.

    Guidelines for specification of graphical elements, illustrated for the batch reactor example (Figures 13a,b, c), apply equally to the continuous distillation column and are not repeated in this example.

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    Developing and promulgating sound consensus standards, recommended practices, and technical

    reports is one of ISAs primary goals. To achieve this goal the Standards and Practices Departmentrelies on the technical expertise and efforts of volunteer committee members, chairmen and reviewers.

    ISA is an American National Standards Institute (ANSI) accredited organization. ISA administers UnitedStates Technical Advisory Groups (USTAGs) and provides secretariat support for InternationalElectrotechnical Commission (IEC) and International Organization for Standardization (ISO) committeesthat develop process measurement and control standards. To obtain additional information on theSocietys standards program, please write:

    ISAAttn: Standards Department67 Alexander DriveP.O. Box 12277Research Triangle Park, NC 27709

    ISBN: 978-1-934394-33-5