Verification Regulation of Load Cell
This regulation is equivalent to OIML International Recommendation R60(2000), Metrological Regulation for Load Cells (Edition 2000). Type approval requirements, test methods and test report format of this regulation are equivalent to R60, and the provisions of metrological controls are added on the base of metrological control requirements of China.
1 Scope
1.2 This regulation is applicable to type approval (or pattern evaluation), initial verification and subsequent verification of load cell (hereinafter referred to as load cell).
1.2 This regulation specifies the principal metrological static characteristics and static evaluation procedures for load cells used in the measurement of mass. It is intended to provide authorities with uniform means for determining the metrological characteristics of load cells used in measuring instruments that are subjected to metrological controls.
1.3 This regulation utilizes the principle that several load cell errors shall be considered together when applying load cell performance characteristics to the permitted error envelope. Thus, it is not considered appropriate to specify individual errors for given characteristics (non-linearity, hysteresis, etc.), but rather to consider the total error envelope allowed for a load cell as the limiting factor. The use of an error envelope allows the balancing of the individual contributions to the total error of measurement while still achieving the intended final result.
Note: The error envelope may be defined as the curves that provide the boundary of the maximum permissible errors (see Table 5) as a function of the applied load (mass) over the measuring range. The combined errors determined may be positive or negative and include the effects of nonlinearity, hysteresis and temperature.
1.4 Instruments which are associated with load cells and which give an indication of mass, are the subjects of separate regulations.
2 Terms and Definitions
The terms most frequently used in the load cell field and their definitions are given below (see 2.6 for an illustration of certain definitions).
The terminology used in this regulation conforms to the International Vocabulary of Basic and General Terms in Metrology and the Vocabulary of Legal Metrology. In addition, for the purposes of this regulation, the following definitions apply.
An index of all the terms defined below is published as a separate sheet at the end of this regulation, to assist in finding the corresponding definitions.
2.1 General terms
2.1.1 Application of load
2.1.1.1 Compression loading
Compressive force applied to a load cell.
2.1.1.2 Tension loading
Tension force applied to a load cell.
2.1.2 Load cell
Force transducer which, after taking into account the effects of the acceleration of gravity and air buoyancy at the location of its use, measures mass by converting the measured quantity (mass) into another measured quantity (output).
2.1.3 Load cell equipped with electronics Load cell employing an assembly of electronic components having a recognizable function of its own.
P-N junction, amplifier, encoder, A/D converter, CPU, I/O interface, etc. (not including strain gauge bridge circuits).
2.1.3.1 Electronic component
The smallest physical entity that uses electron or hole conduction in semiconductors, gases or in a vacuum.
2.1.4 Performance test
Test to verify whether the load cell under test is capable of performing its intended functions.
2.2 Metrological characteristics of a load cell
2.2.1 Accuracy class
Class of load cells that are subject to the same conditions of accuracy.
2.2.2 Humidity symbol
Symbol assigned to a load cell that indicates the conditions of humidity under which the load cell has been tested.
2.2.3 Load cell family
For the purposes of type evaluation/pattern approval, a load cell family consists of load cells that are of:
the same material or combination of materials (for example, mild steel, stainless steel or aluminum);
the same design of the measurement technique (for example, strain gauges bonded to metal);
the same method of construction (for example, shape, sealing of strain gauges, mounting method, manufacturing method);
the same set of specifications (for example, output rating, input impedance, supply voltage, cable details);
one or more load cell groups.
Note: The examples provided are not intended to be limiting.
2.2.3.1 Load cell group
All load cells within a family possessing identical metrological characteristics (for example, class, nmax, temperature rating, etc.).
Note: The examples provided are not intended to be limiting.
2.3 Range, capacity and output terms
2.3.1 Load cell interval
Part of the load cell measuring range into which that range is divided.
2.3.2 Load cell measuring range
Range of values of the measured quantity (mass) forwhich the result of measurement should not be affected by an error exceeding the maximum permissible error (mpe) (see 2.4.9).
2.3.3 Load cell output
Measurable quantity into which a load cell converts the measured quantity (mass).
2.3.4 Load cell verification interval (v)
Load cell interval, expressed in units of mass, used in the test of the load cell for accuracy classification.
2.3.5 Maximum capacity (Emax)
Largest value of a quantity (mass) which may be applied to a load cell without exceeding the mpe (see 2.4.9).
2.3.6 Maximum load of the measuring range (Dmax)
Largest value of a quantity (mass) which is applied to a load cell during test or use. This value shall not be greater than Emax (see 2.3.5). For the limits on Dmax during testing, see A.3.2.4.
2.3.7 Maximum number of load cell verification intervals (nmax)
1 Scope
2 Terms and Definitions
2.1 General terms
2.2 Metrological characteristics of a load cell
2.3 Range, capacity and output terms
2.4 Measurement and error terms
2.5 Influences and reference conditions
2.6 Illustration of certain definitions
3 Units of Measurement
4 Metrological Requirements
4.1 Principle of load cell classification
4.2 Accuracy classes
4.3 Maximum number of load cell verification intervals
4.4 Minimum load cell verification interval
4.5 Supplementary classifications
4.6 Complete load cell classification
4.7 Presentation of information
5 Maximum Permissible Load Cell Errors
5.1 Maximum permissible errors for each accuracy class
5.2 Rules concerning the determination of errors
5.3 Permissible variation of results
5.4 Repeatability error
5.5 Influence quantities
5.6 Measurement standards
6 Requirements for Load Cells Equipped with Electronics
6.1 General Requirements
6.2 Acting upon significant faults
6.3 Functional requirements
6.4 Additional tests
7 Metrological Controls
7.1 Type approval (or pattern evaluation)
7.2 Initial and subsequent verification
7.3 Verification result processing
7.4 Verification interval
Annex A (Mandatory) Test Procedures for Type Approval (or Pattern Evaluation)
Annex B (Informative) Selection of Load Cell(s) for Type Approval (or Pattern Evaluation) — Example
Annex C (Mandatory) Test Report Format - General
Annex D (Mandatory) Test Report Format – Forms
Annex E Format of Verification Certificate, Notification of Verification Result (Inside Pages)
Annex F Index of Terms
Verification Regulation of Load Cell
This regulation is equivalent to OIML International Recommendation R60(2000), Metrological Regulation for Load Cells (Edition 2000). Type approval requirements, test methods and test report format of this regulation are equivalent to R60, and the provisions of metrological controls are added on the base of metrological control requirements of China.
1 Scope
1.2 This regulation is applicable to type approval (or pattern evaluation), initial verification and subsequent verification of load cell (hereinafter referred to as load cell).
1.2 This regulation specifies the principal metrological static characteristics and static evaluation procedures for load cells used in the measurement of mass. It is intended to provide authorities with uniform means for determining the metrological characteristics of load cells used in measuring instruments that are subjected to metrological controls.
1.3 This regulation utilizes the principle that several load cell errors shall be considered together when applying load cell performance characteristics to the permitted error envelope. Thus, it is not considered appropriate to specify individual errors for given characteristics (non-linearity, hysteresis, etc.), but rather to consider the total error envelope allowed for a load cell as the limiting factor. The use of an error envelope allows the balancing of the individual contributions to the total error of measurement while still achieving the intended final result.
Note: The error envelope may be defined as the curves that provide the boundary of the maximum permissible errors (see Table 5) as a function of the applied load (mass) over the measuring range. The combined errors determined may be positive or negative and include the effects of nonlinearity, hysteresis and temperature.
1.4 Instruments which are associated with load cells and which give an indication of mass, are the subjects of separate regulations.
2 Terms and Definitions
The terms most frequently used in the load cell field and their definitions are given below (see 2.6 for an illustration of certain definitions).
The terminology used in this regulation conforms to the International Vocabulary of Basic and General Terms in Metrology and the Vocabulary of Legal Metrology. In addition, for the purposes of this regulation, the following definitions apply.
An index of all the terms defined below is published as a separate sheet at the end of this regulation, to assist in finding the corresponding definitions.
2.1 General terms
2.1.1 Application of load
2.1.1.1 Compression loading
Compressive force applied to a load cell.
2.1.1.2 Tension loading
Tension force applied to a load cell.
2.1.2 Load cell
Force transducer which, after taking into account the effects of the acceleration of gravity and air buoyancy at the location of its use, measures mass by converting the measured quantity (mass) into another measured quantity (output).
2.1.3 Load cell equipped with electronics Load cell employing an assembly of electronic components having a recognizable function of its own.
P-N junction, amplifier, encoder, A/D converter, CPU, I/O interface, etc. (not including strain gauge bridge circuits).
2.1.3.1 Electronic component
The smallest physical entity that uses electron or hole conduction in semiconductors, gases or in a vacuum.
2.1.4 Performance test
Test to verify whether the load cell under test is capable of performing its intended functions.
2.2 Metrological characteristics of a load cell
2.2.1 Accuracy class
Class of load cells that are subject to the same conditions of accuracy.
2.2.2 Humidity symbol
Symbol assigned to a load cell that indicates the conditions of humidity under which the load cell has been tested.
2.2.3 Load cell family
For the purposes of type evaluation/pattern approval, a load cell family consists of load cells that are of:
the same material or combination of materials (for example, mild steel, stainless steel or aluminum);
the same design of the measurement technique (for example, strain gauges bonded to metal);
the same method of construction (for example, shape, sealing of strain gauges, mounting method, manufacturing method);
the same set of specifications (for example, output rating, input impedance, supply voltage, cable details);
one or more load cell groups.
Note: The examples provided are not intended to be limiting.
2.2.3.1 Load cell group
All load cells within a family possessing identical metrological characteristics (for example, class, nmax, temperature rating, etc.).
Note: The examples provided are not intended to be limiting.
2.3 Range, capacity and output terms
2.3.1 Load cell interval
Part of the load cell measuring range into which that range is divided.
2.3.2 Load cell measuring range
Range of values of the measured quantity (mass) forwhich the result of measurement should not be affected by an error exceeding the maximum permissible error (mpe) (see 2.4.9).
2.3.3 Load cell output
Measurable quantity into which a load cell converts the measured quantity (mass).
2.3.4 Load cell verification interval (v)
Load cell interval, expressed in units of mass, used in the test of the load cell for accuracy classification.
2.3.5 Maximum capacity (Emax)
Largest value of a quantity (mass) which may be applied to a load cell without exceeding the mpe (see 2.4.9).
2.3.6 Maximum load of the measuring range (Dmax)
Largest value of a quantity (mass) which is applied to a load cell during test or use. This value shall not be greater than Emax (see 2.3.5). For the limits on Dmax during testing, see A.3.2.4.
2.3.7 Maximum number of load cell verification intervals (nmax)
Contents of JJG 669-2003
1 Scope
2 Terms and Definitions
2.1 General terms
2.2 Metrological characteristics of a load cell
2.3 Range, capacity and output terms
2.4 Measurement and error terms
2.5 Influences and reference conditions
2.6 Illustration of certain definitions
3 Units of Measurement
4 Metrological Requirements
4.1 Principle of load cell classification
4.2 Accuracy classes
4.3 Maximum number of load cell verification intervals
4.4 Minimum load cell verification interval
4.5 Supplementary classifications
4.6 Complete load cell classification
4.7 Presentation of information
5 Maximum Permissible Load Cell Errors
5.1 Maximum permissible errors for each accuracy class
5.2 Rules concerning the determination of errors
5.3 Permissible variation of results
5.4 Repeatability error
5.5 Influence quantities
5.6 Measurement standards
6 Requirements for Load Cells Equipped with Electronics
6.1 General Requirements
6.2 Acting upon significant faults
6.3 Functional requirements
6.4 Additional tests
7 Metrological Controls
7.1 Type approval (or pattern evaluation)
7.2 Initial and subsequent verification
7.3 Verification result processing
7.4 Verification interval
Annex A (Mandatory) Test Procedures for Type Approval (or Pattern Evaluation)
Annex B (Informative) Selection of Load Cell(s) for Type Approval (or Pattern Evaluation) — Example
Annex C (Mandatory) Test Report Format - General
Annex D (Mandatory) Test Report Format – Forms
Annex E Format of Verification Certificate, Notification of Verification Result (Inside Pages)
Annex F Index of Terms
