1、BRITISH STANDARD BS 7986:2005 Data quality metrics for industrial measurement and control systems Specification ICS 25.040.40; 35.240.50 BS 7986:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 8 April 2005 BSI 8 April 2005 First publishe
2、d July 2001 Second edition April 2005 The following BSI references relate to the work on this British Standard: Committee reference AMT/7 Draft for comment 04/30077426 DC ISBN 0 580 45425 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Tec
3、hnical Committee, AMT/7, Industrial communications: Process measurement and control, including Fieldbus, upon which the following bodies were represented: Department of Trade and Industry Emerson Process Management Ltd. Foxboro Great Britain Ltd. Health and Safety Executive Measurement Technology Lt
4、d. Rockwell Automation Ltd. SafetyBUS p Club International e.V. Schneider Electric Ltd. WAGO Ltd. Amendments issued since publication Amd. No. Date CommentsBS 7986:2005 BSI 8 April 2005 i Contents Page Committees responsible Inside front cover Foreword iii Introduction 1 1S c o p e 1 2 Normative ref
5、erences 1 3T e r m s a n d d e f i n i t i o n s 1 4 Functional requirements and intended applications for data quality metrics 7 5 Data quality and function blocks 11 6 Data quality for analogue measurement and monitoring parameters 14 7 Data quality for discrete parameters 22 8 Data quality for an
6、alogue control and actuation parameters 22 9 Data quality for discrete control and actuation parameters 26 10 Support for maintenance 29 11 Propagation of data and quality through function blocks 33 12 Specifications for transitions during faults 39 Annex A (informative) Relationship to ISO/IEC GUM:
7、1995 40 Annex B (informative) Data quality and other technologies 41 Annex C (informative) VV and VU examples for trending during loss-of-variable 47 Annex D (informative) VV and VU examples for recovery from loss-of-variable 49 Bibliography 51 Figure 1 Use of data quality to improve control 10 Figu
8、re 2 Mapping between generic device status and application specific alerts 10 Figure 3 Process related data flow in a function block application 12 Figure 4 Data flow for monitoring function blocks 13 Figure 5 Data flow for control and actuation function blocks 14 Figure 6 State transition diagram f
9、or VUstatus 22 Figure 7 Validated analogue control or actuator function block 23 Figure 8 Validated discrete control or actuator function block 26 Figure 9 State transition diagram for device status 32 Figure 10 VDstatus for current and predicted faults 33 Figure 11 A function block output based on
10、input data and quality attributes 34 Figure 12 A mass flow function block 34 Figure C.1 Loss-of-variable with constant VV 47 Figure C.2 Loss-of-variable with trending VV 48 Figure D.1 Immediate recovery from loss-of-variable condition 49 Figure D.2 Spike disturbance with immediate recovery 50 Table
11、1 Primary states 10 Table 2 VVstatus quality values 15 Table 3 VVstatus limit values 15 Table 4 Sub-states for BAD 15 Table 5 Sub-states for UNCERTAIN 16 Table 6 Sub-states for GOOD (NON-CASCADE) 17 Table 7 Sub-states for GOOD (CASCADE) 18BS 7986:2005 ii BSI 8 April 2005 Table 8 VUstatus values 19 T
12、able 9 Sub-states for BLIND 19 Table 10 Sub-states for DAZZLED 19 Table 11 Sub-states for BLURRED 20 Table 12 Sub-states for CLEAR 20 Table 13 Sub-states for SECURE (COMMON) 20 Table 14 Sub-states for SECURE (DIVERSE) 20 Table 15 Sub-states for CLEAR CASCADE 20 Table 16 Sub-states for SECURE CASCADE
13、 21 Table 17 Validated values 22 Table 18 Settings for control strategy 24 Table 19 VAAstatus values 25 Table 20 Sub-states for TRACKING 25 Table 21 Sub-states for IMPAIRED 25 Table 22 Sub-states for INCAPABLE 26 Table 23 VADstatus values 28 Table 24 Sub-states for TRACKING 28 Table 25 Sub-states fo
14、r IMPAIRED 28 Table 26 Sub-states for INCAPABLE 29 Table 27 VDstatus values 29 Table 28 Sub-states for UNCHECKED 30 Table 29 Sub-states for NOMINAL 30 Table 30 Sub-states for DEVICE-ON-TEST 30 Table 31 Sub-states for LOW PRIORITY MAINTENANCE 30 Table 32 Sub-states for HIGH PRIORITY MAINTENANCE 31 Ta
15、ble 33 Sub-states for CRITICAL MAINTENANCE 31 Table B.1 MIMOSA CRIS measurement event status 44 Table B.2 Health grade 44 Table B.3 Priority type 44 Table B.4 Asset health 44 Table B.5 Asset remaining life estimates 45BS 7986:2005 BSI 8 April 2005 iii Foreword This British Standard was prepared by T
16、echnical Committee AMT/7. It supersedes BS 7986:2001. This revised edition of BS 7986 incorporates the recommendations submitted by members of IEC in response to the circulation as a new work item proposal of BS 7986:2001. NOTE This British Standard is claimed by Invensys to be subject to intellectu
17、al property rights owned by Invensys 1) . Invensys has granted users of the British Standard a non-exclusive, non-transferable, perpetual right to use the technical information in this British Standard in developing, making, using and selling products which conform to this British Standard. It shoul
18、d be noted that SEVA TMis a trademark of Invensys, no rights to which are granted herein, all rights remain reserved. Annex A, Annex B, Annex C and Annex D are informative. This publication does not purport to include all necessary provisions of a contract. Users are responsible for its correct appl
19、ication. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages 1 to 51 and a back cover. The BSI copyright notice displayed in this document indicates when the
20、document was last issued. 1)Invensys Intellectual Property Department, 33 Commercial Street, Foxboro, MA 02035, USAiv blankBS 7986:2005 BSI 8 April 2005 1 Introduction Digital communication technology is now widely used for data transfer in industrial measurement and control systems. It enables inte
21、lligent devices to communicate not only their current values but also related data quality parameters that greatly increase the value and usefulness of the data. Intelligent devices typically support internal functions for performance compensation and self-checking to improve the reported data quali
22、ty. The results of these checks need to be communicated using generic parameters that enhance the value of reported device measurement inputs and control outputs. These additional parameters and attributes are known as “data quality metrics”. 1 Scope This standard specifies functional requirements,
23、intended applications and data quality metrics to be used in industrial measurement and control systems. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the
24、 latest edition of the referenced document (including any amendments) applies. PD 6461-3:1995, General metrology Guide to the Expression of Uncertainty in Measurement (GUM). NOTE 1 This document is also known as ISO/IEC Guide to the Expression of Uncertainty in Measurement (GUM), 1995. NOTE 2 The re
25、lationship between PD 6431-3 and BS 7986 is explained in Annex A. 3 Terms and definitions For the purposes of this British Standard, the following terms and definitions apply. NOTE This edition omits the terms “offline”, “unvalidated” and “replaced” because they are deemed to be control modes rather
26、 than status states. 3.1 agent consumer of measurement data and/or the originator of command data that is transferred through a channel 3.2 backcalc parameter representing data in an actuator or control function block which is made available for access by a preceding control function block for manag
27、ement or initialisation NOTE The backcalc value is usually the working setpoint or output. 3.3 BAD VVstatus during which the associated VV is not useful and accompanying sub-status values support diagnosis and control management 3.4 BLIND VUstatus during which the associated VV is based on historica
28、l data NOTE 1 BLIND indicates that, based on available diagnostic data, the device or function block logic concludes that the input value is not representative of the process variable and sufficient evidence exists to assert that the problem is permanent. NOTE 2 The VV is projected from past history
29、 and uncertainty increases at a rate consistent with past history and any limits configured into the device. 3.5 BLURRED VUstatus during which the associated VV reports real measurement-derived data but a known problem exists for which compensation has been applied, so the reported value is the best
30、 estimate of the current value and the uncertainty has been increased accordinglyBS 7986:2005 2 BSI 8 April 2005 3.6 channel complete sequence of related entities involved in the transfer and manipulation of data moving between a sensor or actuator and an agent NOTE Practical examples of channels in
31、clude: a) a flow measurement channel comprising an orifice plate, DP cell, totalizer, communication network or fieldbus and function blocks linked to maintenance agents; b) a flow output channel including control agents linked to split-range function blocks, communication network, valve positioner a
32、nd valve. 3.7 CLEAR VUstatus during which the associated VV is valid, on-line and within nominal data sheet specification values 3.8 CLEAR CASCADE VUstatus during which the associated VV can be used for control and the accompanying sub-status values support control management 3.9 COMMON MODE FAULT f
33、ault that occurs throughout a set of measurement channels where they share common elements NOTE An example of this could be where a shared process connection breaks or becomes blocked and affects all measurements using the connection. 3.10 CRIS Common Relational Information Schema MIMOSA specificati
34、on including measurements to support asset management 3.11 CRITICAL MAINTENANCE VDstatus during which the designer believes, based on available data and diagnostics, that a critical condition exists which could damage the plant or the environment NOTE An example of this could be the leakage of proce
35、ss fluids from a perforated diaphragm. 3.12 data quality metrics defined set of quality attributes added to function block data to assist their interpretation by interested agents 3.13 DAZZLED transient VUstatus during which the associated VV is based on historical data whilst the fault condition is
36、 assessed NOTE 1 DAZZLED indicates that based on available diagnostic data, the device or function block logic concludes that the input value is not representative of the process variable, but needs more data to determine if the problem is permanent. NOTE 2 The VV is projected from past history and
37、the uncertainty increases at a rate consistent with past history and any limits configured into the device. NOTE 3 This status could be reported during a test procedure of limited duration which prevents measurement function (intrusive test). 3.14 DEVICE-ON-TEST VDstatus during which the associated
38、device or group of devices is undergoing an intrusive test or re-calibration action during which normal functions might be disturbed or inhibited NOTE This status can be self-initiated or externally requested.BS 7986:2005 BSI 8 April 2005 3 3.15 fieldbus digital communication system designed for use
39、 between sensors, controllers and actuators in automation applications 3.16 Foundation Fieldbus industry consortium with interests in fieldbus communications, function block applications and device description languages 3.17 function block software functional unit comprising an individual, named cop
40、y of a data structure and associated operations specified by a corresponding function block type 3.18 GOOD (CASCADE) VVstatus during which the associated VV can be used for control and the accompanying sub-status values support control management 3.19 GOOD (NON-CASCADE) VVstatus during which the ass
41、ociated VV is derived from valid process measurement and monitoring data and the accompanying sub-status values support alarm management 3.20 HART HART Communication Foundation industry consortium with interests in fieldbus communications, function block applications and device description languages
42、 3.21 HIGH PRIORITY MAINTENANCE VDstatus where the designer believes, based on local diagnostics, that a major fault or incipient problem has been detected in the associated device or group of devices NOTE Examples of this are where the main measurement is BLIND or the device is expected to become f
43、aulty within X 2hours, where X 2is configurable. 3.22 intelligent actuation and measurement IAM combined use of instrument functions and communication services to support the control, maintenance and the technical management of industrial automation 3.23 intelligent instrument device where embedded
44、computing capability is included as part of a measurement, control or actuation device 3.24 intrusive testing test procedure that causes measurement disturbances which are not related to process values 3.25 limit-status VVstatus component indicating limit conditions affecting the accompanying VV 3.2
45、6 loss-of-variable condition condition when the measured value is believed to be unrepresentative of the actual process valueBS 7986:2005 4 BSI 8 April 2005 3.27 LOW PRIORITY MAINTENANCE VDstatus during which the designer believes, based on local diagnostics, that a minor fault or incipient problem
46、has been detected in the associated device or group of devices NOTE Examples of this are: a) where the re-calibration time has passed and the main measurement is BLURRED; b) in a multi-measurement device where the main measurement is CLEAR and one or more of the secondary measurements is BLURRED or
47、BLIND; c) where the device is expected to become faulty within X 1hours, where X 1is configurable. 3.28 Machinery Information Management Open Systems Alliance MIMOSA industry consortium with interests in asset management, fault diagnosis and maintenance 3.29 NOMINAL VDstatus during which the designe
48、r believes maintenance is not needed by the associated device or group of devices 3.30 non-intrusive testing test that does not disturb the measurement value 3.31 outputSP output parameter from an analogue control function block for use as a setpoint input by another control block or an actuation fu
49、nction block 3.32 outputSPD output parameter from a discrete control function block for use as a setpoint input by another control block or an actuation function block 3.33 PROFIBUS-PA specification issued by Profibus User Group, an industry consortium with interests in fieldbus communications, function block applications and device description languages 3.34 SECURE (COMMON) VUstatus during which th
