GB/T 7721-2017 English PDF

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GB/T 7721-2017: Continuous totalizing automatic weighing instruments (belt weigher)
Status: Valid

GB/T 7721: Historical versions

Standard ID	USD	BUY PDF	Lead-Days	Standard Title (Description)	Status
GB/T 7721-2017	2989	Add to Cart	16 days	Continuous totalizing automatic weighing instruments (belt weigher)	Valid
GB/T 7721-2007	RFQ	ASK	6 days	Continuous totalizing automatic weighing instruments (electronic belt weigher)	Obsolete
GB/T 7721-1995	519	Add to Cart	4 days	Electronic belt weighers	Obsolete
GB 7721-1987	RFQ	ASK	3 days	Electronic belt conveyor scale	Obsolete

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GB/T 9081   GB/T 21296.2   GB/T 21296.3   GB/T 7724   GB/T 7722   

Basic data

Standard ID: GB/T 7721-2017 (GB/T7721-2017)
Description (Translated English): Continuous totalizing automatic weighing instruments (belt weigher)
Sector / Industry: National Standard (Recommended)
Classification of Chinese Standard: N13
Classification of International Standard: 17.100
Word Count Estimation: 150,117
Date of Issue: 2017-12-29
Date of Implementation: 2018-07-01
Issuing agency(ies): General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China

GB/T 7721-2017: Continuous totalizing automatic weighing instruments (belt weigher)

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Continuous totalizing automatic weighing instruments(belt weighers) ICS 17.100 N13 National Standards of People's Republic of China Replacing GB/T 7721-2007 Continuously accumulated automatic weighing device (belt scale) (beltweighers) [OIMLR50.2014(E),MOD] Published on.2017-12-29 2018-07-01 Implementation General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China China National Standardization Administration released Directory Foreword V 1 Scope 1 2 Normative references 1 3 Terms and Definitions 2 3.1 General definition 2 3.2 Structure 3 3.3 Measurement Characteristics 8 3.4 Indications and Errors 10 3.5 Influences and Reference Conditions 12 3.6 Test 12 3.7 Abbreviations and Symbols 13 3.8 Basic Relationship 14 4 Product Model 14 5 Measurement requirements 14 5.1 Accuracy Level 14 5.2 Maximum allowable error [Applicable to cases where the load is greater than or equal to the minimum cumulative load (∑min)] 14 5.3 Consistency Between Multiple Indicators 15 5.4 Minimum cumulative load 15 5.5 Minimum flow 15 5.6 Unit of measure 16 5.7 Simulation Test in Type Inspection 16 5.8 Field Tests in Type Examination 18 6 Technical Requirements 19 6.1 Applicability of Use 19 6.2 Rated operating conditions 19 6.3 Operational Security 19 6.4 cumulative display and printing device 20 6.5 Zero-setting device 22 6.6 tape correction device 22 6.7 Displacement Sensor 22 6.8 Belt Conveyor Connection with Conveyor 23 7 Additional requirements for electronic belt weighers 24 7.1 General Requirements 24 7.2 applies 24 7.3 Response to Significant Increases 24 7.4 Indicator Display Test 24 7.5 Functional Requirements 24 7.6 Interface 25 7.7 Data Storage Device 25 7.8 Software 26 7.9 Security Performance 26 7.10 Load cell 26 7.11 Manufacturing 26 7.12 Installation 27 8 Test methods 27 8.1 General Test Requirements 27 8.2 Control weights and standard weights 27 8.3 Simulation test (test with static load without belt conveyor) 27 8.4 Test Load Quality Truth 28 8.5 Quality indication 28 8.6 Relative Error Calculation 28 8.7 Inspections and Tests 29 9 Inspection Rules 29 9.1 Type Inspection 29 9.2 Factory Inspection 33 9.3 Checking in Use 33 10 Signs, Packaging, Transport and Storage 35 10.1 Mark 35 10.2 Packaging 36 10.3 Transportation 37 10.4 Storage 37 Appendix A (Normative) Continuous cumulative automatic weighing test method 38 A.1 Type Examination Review 38 A.1.1 File 38 A.1.2 Comparison of Structures and Documents 38 A.1.3 Metrological characteristics 38 A.1.4 Technical requirements 38 A.1.5 Functional Requirements 38 A.2 General requirements for the instrument under test 38 A.2.1 Power Supply Stabilization Time 38 A.2.2 Zeroing 38 A.2.3 Temperature 38 A.2.4 Recovery 38 A.2.5 Warm-up time 39 A.2.6 Automatic Zeroing 39 A.2.7 Error Assessment (Calculate Relative Errors in accordance with 8.6) 39 A.3 Test item 39 A.4 Dosing performance test 40 A.4.1 General conditions 40 A.4.2 Warm-up time test (7.5.3) 40 A.4.3 Material Test Control Method (8.1) 40 A.4.4 Simulation test of static load (8.3) 40 A.5 Additional Functions 42 A.5.1 Consistency Between Multiple Indicators 42 A.5.2 Adjustments in Automatic Operation Mode 42 A.5.3 Protection of components and preset controls 42 A.5.4 Cumulative indication and printing device 42 A.5.5 Maintaining the cumulative load after a power failure 42 A.5.6 DC supply voltage or battery voltage change 42 A.6 Impact Factors and Interference Tests 42 A.6.1 Overview 42 A.6.2 Impact Factor Test 43 A.6.3 interference test 50 A.7 Dosing characteristics 57 A.7.1 Simulation test repeatability 57 A.7.2 cumulative display discrimination 57 A.7.3 Accumulated Display Zero Accuracy 57 A.7.4 Zero Stability 58 A.8 On-site no-load test 58 A.8.1 Zero maximum allowable error 58 A.8.2 Zero Accuracy of Accumulative Display 58 A.8.3 Maximum deviation test for zero load 59 A.9 Field Material Test 59 A.9.1 Test Conditions and Test Materials 59 A.9.2 Control Methods 59 A.9.3 Material Testing 60 A.10 Additional Inspection and Testing of Software-Controlled Digital Devices and Weighing Instruments 60 A.10.1 Embedded Software Devices and Scales 60 A.10.2 Personal Computers and Other Programmable or Loadable Software Devices 60 A.10.3 Data Storage Devices 61 A.10.4 Test Report Form 62 A.11 Safety Test Requirements 62 Appendix B (Normative) Continuous Accumulative Automatic Weighing Instrument Test Report Format 63 B.1 Description of the test report format 63 B.2 Commentary requirements 63 B.3 Belt Scale Logo 64 B.4 Overview of related types 67 B.5 Test Equipment for Type Examination 69 B.6 Summary of checklist 71 B.7 Type Examination Summary 73 B.8 Simulation test 75 B.8.1 Warm-up time 76 B.8.2 Simulation speed deviation 77 B.8.3 Offset loading 78 B.8.4 Zero-setting device 79 B.8.5 Impact Factor Test 81 B.8.6 interference test 96 B.8.7 Measurement Performance Test 110 B.9 Field test 114 B.9.1 Overview 114 B.9.2 Maximum allowable error for zero check 116 B.9.3 Zeroing display discrimination 117 B.9.4 Field Material Testing 118 B.10 Checklist 121 Appendix C (Informative Appendix) This section of the Standard and the OIMLR50.2014(E) “Continuous Accumulated Automatic Weighing Instrument” (2014E) Regulation 138 Appendix D (informative annex) This standard and OIMLR50.2014 (E) "Continuous Accumulative Automatic Weighing Apparatus" technical differences and their reasons 140

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009. This standard replaces GB/T 7721-2007 "continuous cumulative automatic weighing (electronic belt scale)". Main compared with GB/T 7721-2007 The technical changes are as follows. --- Increased the accuracy level of the 0.2 product (see 5.1). --- Increased the minimum cumulative load requirements (see 5.4). --- Increased requirements for component protection and seals and preset controls (see 6.3.7). --- Increased the requirements of the tape correction device (see 6.6). --- Increased anti-interference test requirements (see 7.1.1). --- Increased durability test requirements (see 7.1.2). --- Increased requirements for interfaces, data storage devices, and software (see 7.6, 7.7, 7.8). This standard uses the redrafted law to amend the International Legal Organization No. 50 International Recommendation OIMLR50.2014(E) “Continuous Accumulation Automatic weighing instrument (belt scale)" (R50-1, R50-2, R50-3). This standard has more structural adjustments than OIMLR50.2014(E). This standard and OIMLR50 are listed in Appendix C. The.2014(E) chapter numbering control list. There are technical differences between this standard and OIMLR50.2014(E). The terms involved in these differences have passed the margin on the outside of the page. The vertical single line at the white position is marked, and a list of the corresponding technical differences and their causes is given in Appendix D. This standard also made the following editorial changes. --- Appendices A and B of this standard to the second part (R50-2) and third part (R50-3) of the R50 International Recommendation. Please note that some of the contents of this document may involve patents. The issuing agency of this document does not assume responsibility for identifying these patents. This standard is proposed by China Light Industry Federation. This standard is under the jurisdiction of the National Weighing Instrument Standardization Technical Committee (SAC/TC97). This standard was drafted by. Semimo Electric Co., Ltd., Shanxi Xinyuan Automation Instrumentation Co., Ltd., Qingdao Metrology and Technology Research Institute, Tongling San Aisi Electronic Co., Ltd., Shandong Jinzhong Technology Group Co., Ltd., Beijing Chunhai Technology Development Co., Ltd., Nanjing San Ai Industrial Control Co., Ltd. The main drafters of this standard are. Li Da, He Fusheng, Liang Yuewu, Wang Junguo, Xu Housheng, Zhang Jiaying, Li Chunxiao, and Lu Qinsheng. The previous versions of the standard replaced by this standard are. --- GB 7721-1987, GB/T 7721-1995, GB/T 7721-2007. Continuously accumulated automatic weighing device (belt scale)

1 Scope

This standard stipulates terms, product models, requirements, inspections of belt conveyer type continuous cumulative automatic weighing instruments (hereinafter referred to as “belt scales”). Methods and rules, signs, packaging, transportation and storage. This standard also provides standardized requirements and test procedures for evaluating the metrological characteristics or technical characteristics of belt weighers in a traceable manner. form. This standard applies to. --- Using the principle of gravity, a continuous weighing method to determine and accumulate the weight of bulk material. --- Belt weigher used with single speed belt conveyors, variable speed or multi-speed belt conveyors.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article Pieces. For undated references, the latest version (including all amendments) applies to this document. GB/T 191 packaging, storage and transportation logo GB/T 2423.1-2008 Environmental testing for electric and electronic products Part 2. Test methods Test A. Low temperature (IEC 60068-2- 1.2007, IDT) GB/T 2423.2-2008 Environmental testing for electric and electronic products Part 2. Test methods Test B. High temperature (IEC 60068-2- 2.2007,IDT) GB/T 2423.3-2016 Environmental testing - Part 2. Test method test Cab. Constant moisture heat test (IEC 60068-2- 78.2001, IDT) GB/T 2423.4-2008 Environmental testing for electric and electronic products Part 2. Test methods Test Db. Alternating heat test method Method (IEC 60068-2-30.2005, IDT) GB/T 2424.1-2015 Environmental test part 3. supporting documents and guidelines for low temperature and high temperature test (IEC 60068-3-1. 2011, IDT) GB/T 2424.2-2005 Guidelines for Damp Heat Tests for Environmental Testing of Electrical and Electronic Products (IEC 60068-3-4.2001, IDT) GB/T 2887 Computer Site General Specifications GB/T 4167 weight GB/T 4879 rust-proof packaging GB/T 5048 moisture-proof packaging GB/T 7551-2008 load cell GB/T 7724 electronic weighing instrument GB/T 13384 general technical conditions for mechanical and electrical product packaging GB 14249.1-1993 Electronic weighing equipment safety requirements GB/T 14250 weighing terms GB/T 15395 General Specifications for Electronic Equipment Cabinets GB/T 17214.2 Working conditions for industrial process measurement and control devices Part 2. Power (IEC 60654-2, IDT) ......

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