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JJF 1016 The Rules for drafting program of pattern evaluation of measuring instruments and JJF 1059.1-2012 Evaluation and expression of uncertainty in measurement together constitute the basic series specifications for the formulation of this program.
The requirements and methods for test items in this program were prepared by reference to GB/T 17614.1-2015 Transmitters for use in industrial-process control systems - Part 1: Methods for performance evaluation, GB/T 28474.1-2012 Pressure/Differential-pressure transmitter for use in industrial-process measure and control systems - Part 1: General specification and JJG 882 Pressure transmitters. This program also refers to normative documents such as GB/T 18271 Process measurement and control devices - General methods and procedures for evaluating performance, GB/T 17212 Industrial-process measurement and control - Terms and definitions, GB/T 17626 Electromagnetic compatibility - Testing and measurement techniques and GB/T 2423.2 Environmental testing - Part 2: Test methods - Tests B: Dry heat.
This program is issued for the first time.
Program of pattern evaluation of pressure transmitters
1 Scope
This program is applicable to the pattern evaluation of pressure (including positive, negative, differential and absolute pressure) transmitters with classification code of 12340500, but not applicable to that of pneumatic transmitters and force/moment-balance transmitters.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this program:
JJG 882 Pressure transmitters
JJF 1001 General terms in metrology and their definitions
GB/T 2423.2 Environmental testing - Part 2: Test methods - Tests B: Dry heat
GB/T 17212 Industrial-process measurement and control - Terms and definitions
GB/T 17614.1-2015 Transmitters for use in industrial-process control systems - Part 1: Methods for performance evaluation
GB/T 17626 Electromagnetic compatibility - Testing and measurement techniques
GB/T 18271.2 Process measurement and control devices - General methods and procedures for evaluating performance - Part 2: Tests under reference conditions
GB/T 18271.3 Process measurement and control devices - General methods and procedures for evaluating performance - Part 3: Tests for the effects of influence quantities
GB/T 28474.1-2012 Pressure/Differential-pressure transmitter for use in industrial-process measure and control systems - Part 1: General specification
For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
3 Terms and definitions
3.1 conformity
goodness of fit between the calibration curve and the specified characteristic curve (straight line, logarithmic curve, parabola, etc.)
[GB/T 17212, P2.2.2.12]
3.2 independent conformity
goodness of fit between the calibration curve for the transmitter and the specified characteristic curve, with the maximum deviation smallest
[GB/T 17212, P2.2.2.13]
3.3 terminal-based conformity
goodness of fit between the calibration curve for the transmitter and the specified characteristic curve, with the upper and lower limits of the input and output curves coincided with each other
[GB/T 17212, P2.2.2.14]
3.4 zero-based conformity
goodness of fit between the calibration curve for the transmitter and the specified characteristic curve, with the lower range limits of the two curves coincided with each other and the maximum positive deviation equal to the maximum negative deviation
[GB/T 17212, P2.2.2.15]
3.5 residual change in value
difference between the two results measured at the initial state when the test starts and at the time when the test ends and the initial state recovers
3.6 step response time
duration between the moment when the input value of a measuring instrument or system suddenly changes between two specified constant values and the moment when the corresponding indicated value reaches the specified limit of its final stable value
[JJF 1001, 7.23]
3.7 dead band
maximum interval impossible for detectable change in corresponding values when the measured value changes bidirectionally
[JJF 1001, 7.17]
Note 1 to entry: A dead band may be related to the rate of change.
4 General
Pressure transmitter is a type of instrument which converts the pressure variables into standardized transmissible output signals; where, both show a specified continuous function relationship (linear function in general). It is mainly used for the measurement and control of pressure parameters in industrial processes.
Standard output signals of pressure transmitters include: DC signals of 0 mA~10 mA, 4 mA~20 mA (or 1 V~5 V), etc., as well as digital signals meeting the requirements of various communication protocols and other standard signals with special requirements.
5 Legal management requirements
5.1 Unit of measurement
The legal unit of measurement of Pa (pascal) or its decimal multiples (kPa, MPa, etc.) shall be used for pressure transmitters.
5.2 Accuracy grade
The accuracy grade of pressure transmitters may be selected from the following series: 0.05, 0.075, 0.1, 0.2 (0.25), 0.5, 1 and 1.5.
5.3 Marking and identification
5.3.1 Legal measurement marks generally include the following contents:
——Instrument pattern approval mark and number (corresponding positions shall be left on test prototypes);
——Product quality seal and certificate (this item may be set separately from the measuring instrument itself).
5.3.2 The pressure transmitter identification generally includes the following contents:
——Name, specification/model, manufacturer’s name or trademark;
——Accuracy grade (or maximum allowable error);
——Year and number of manufacture and lot number;
——Explosion-proof identification (if any).
5.4 Requirements for external structure design
Pressure transmitters shall be of closed structure design.
5.5 Technical documents and test prototypes provided for review
5.5.1 Technical documents provided for review
——Prototype photo;
——Product standard and inspection methods;
——General assembly drawing, circuit diagram and drawing of main parts;
——Operating instructions;
——Test report prepared by the manufacturer or technical organization.
5.5.2 Number of prototypes provided
For a single product, one to three prototypes shall be provided; for series products, those with upper and lower limits of measurement range shall be included, and one to three prototypes shall be provided for each type of product; or the number may be determined by the metrological administrative department of the government accepting the application and the technical organization undertaking the test according to the technical documents and product specifications provided by the applicant.
6 Measurement requirements
6.1 Indication error
The indication errors of pressure transmitters are classified according to accuracy grade and shall meet those specified in Table 1.
6.2 Return difference
The return difference of pressure transmitters shall meet those specified in Table 1.
6.3 Repeatability
The repeatability of pressure transmitter shall meet those specified in Table 1.
6.4 Terminal-based conformity
The terminal-based conformity of pressure transmitter shall meet those specified in Table 1.
6.5 Dead band
The dead band of pressure transmitter shall meet those specified in Table 1.
Table 1 Items related to accuracy grade
Item Accuracy grade
Grade 0.05 Grade 0.075 Grade 0.1 Grade 0.2
(Grade 0.25) Grade 0.5 Grade 1.0 Grade 1.5
Allowable value
Indication error ±0.05% ±0.075% ±0.1% ±0.2%
(±0.25%) ±0.5% ±1.0% ±1.5%
Return difference ≤0.04% ≤0.06% ≤0.08% ≤0.16%
(≤0.2%) ≤0.4% ≤0.8% ≤1.2%
Repeatability ≤0.025% ≤0.04% ≤0.05% ≤0.10%
(≤0.125%) ≤0.25% ≤0.5% ≤0.75%
Terminal-based conformity ≤0.04% ≤0.06% ≤0.08% ≤0.16%
(≤0.2%) ≤0.4% — —
Dead band
(Input measuring range) ≤0.05% ≤0.075% ≤0.1% ≤0.2%
(≤0.25%) ≤0.5% — —
Notes:
1 The allowable values are expressed by the percentage of output measuring range.
2 If the measuring range of a pressure transmitter is less than or equal to 6 kPa, the influence of dead band may be ignored.
3 If the accuracy grade is inferior to Grade 0.5, the items of terminal-based conformity and dead band may be omitted.
4 If the technical indexes of terminal-based conformity, repeatability and dead band in the company standard of the pressure transmitter manufacturer are higher than those in this program, they shall be subjected to the requirements of the company standards.
5 In the company standards of pressure transmitter manufacturers, zero-based conformity or independent conformity, if used, may replace the terminal-based conformity, with the technical indexes referring to those of the terminal-based conformity.
7 General technical requirements
7.1 Normal working conditions
The lower limit of pressure transmitter at normal working environment temperature is preferably selected from the following data: -55℃, -40℃, -30℃, -25℃, -20℃, -10℃ and 0℃.
The upper limit of pressure transmitter at normal working environment temperature is preferably selected from the following data: 50℃, 60℃, 70℃, 80℃, 85℃, 90℃, 100℃ and 125℃.
Relative humidity: 5%~95% (at 25℃).
Atmospheric pressure: 86 kPa~106 kPa.
AC external magnetic field: ≤400 A/m.
Rated working voltage: 220 V AC, 24 V DC, ±15V DC or battery power supply, etc.
7.2 Reference working conditions
7.2.1 Ambient temperature: Grade 0.05, Grade 0.075: 20℃±2℃; Grade 0.1 and below: 20℃±5℃; the temperature change per 10 min shall not be greater than 1℃.
7.2.2 Relative humidity: ≤80%.
7.2.3 Power supply: It shall conform to the performance indicated by the power supply indexes marked on the test prototype.
7.2.4 Atmospheric pressure: 86 kPa~106 kPa.
7.2.5 Magnetic field: No external magnetic field that affects the output of a pressure transmitter.
7.2.6 Vibration: No vibration source that affects the output of a pressure transmitter.
7.3 Functional characteristics
If a pressure transmitter has the following functional characteristics, the manufacturer shall give the technical parameters of the following characteristics.
7.3.1 Input resistance
At the power input end, the resistance presented to the DC signal is expressed by Ω.
Note: It is only applicable to pressure transmitters using wired signal transmission.
7.3.2 Load resistance (non-test item)
The manufacturer shall specify the range of load resistance.
7.3.3 Power supply voltage (non-test item)
The manufacturer shall specify the nominal value and allowable variation limits of the power supply voltage; in case of AC power supply, it is necessary to give the nominal value and allowable variation limits of frequency.
7.3.4 Electrical power consumption (non-test item)
For pressure transmitters powered by AC, the effective (root mean square) value of consumed volt-ampere shall be given.
For pressure transmitters powered by DC, the effective value of consumed watt shall be given.
7.3.5 Output ripple
For pressure transmitters powered by DC, the peak-to-peak value and main frequency component range of allowable ripple content shall be given.
Note: It is not applicable to pressure transmitters using digital signal transmission.
7.3.6 Adjustment limits of lower range limit and measuring range
The adjustment limits of lower range limit and measuring range may be classified into two categories: one is the adjustment designed to compensate the manufacturing tolerance or other small deviations; the other is the adjustment (range ratio) designed to increase or decrease the input signal range to adapt to the specified output range.
7.3.7 Differential gap
If a pressure transmitter has the switching function, the manufacturer shall give the difference between the input value that triggers the switching action and the input value that can just cancel the switching action.
7.4 Appearance
The shell surface shall be smooth and intact without scratches and other damages.
Product nameplates, plates, etc. shall be complete and firmly fixed on the shell.
Product shall be free of sundries, such as dust and residue, inside.
7.5 Initial drift
At 10% and 90% of the measuring range, the variation of output value shall not exceed the absolute value of indication error.
7.6 Long-term drift
A long-term drift test with a cycle of 30d shall be carried out. The variation of output value shall not exceed the absolute value of indication error.
Note: A prototype may be taken separately for this test.
7.7 Frequency response
The frequency response is a dynamic index item for pressure transmitter, and a frequency response diagram may be given through negotiation with the manufacturer.
7.8 Step response
The step response is a dynamic index item for pressure transmitter, and the test requirements for step response may be determined through negotiation with the manufacturer.
Under each test condition, the time required to reach steady-state value and remain it within 1% of measuring range shall be measured.
7.9 Items related to influence quantity
The technical indexes of pressure transmitters related to the influence quantity shall comply with the requirements according to their accuracy grades. The value corresponding to the accuracy grade may be selected from Table 2.
7.9.1 Ambient temperature
The allowable values of the influence of ambient temperature on the lower range limit and measuring range of pressure transmitters may be selected from Table 2 according to their accuracy grades, or expressions equivalent to the allowable values in Table 2 may be given through negotiation with the user.
7.9.2 Humidity
The allowable values of the influence of humidity on the lower range limit and measuring range of pressure transmitters may be selected from Table 2 according to their accuracy grades.
After the test, a visual inspection shall be carried out to see whether spark-over, condensation accumulation or elements damage is occurred.
After another 24 h under environmental conditions, check whether the indication error of the pressure transmitter meets the requirements of 6.1.
7.9.3 Vibration (sinusoidal)
The allowable values of the influence of vibration (sinusoidal) on the lower range limit and measuring range of pressure transmitters may be selected from Table 2 according to their accuracy grades.
Table 2 Items related to influence quantity
S.N. Item Unit Accuracy grade
Grade 0.05 Grade 0.075 Grade 0.1 Grade 0.2
(Grade 0.25) Grade 0.5 Grade 1.0 Grade 1.5
Allowable value①
1 Ambient temperature② Variation of lower range limit %/℃ 0.005 0.0075 0.01 0.02
(0.025) 0.05 0.1 0.1
Variation of measuring range 0.01 0.015 0.02 0.05
(0.05) 0.1 0.2 0.2
2 Humidity Variation of lower range limit % 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Variation of measuring range 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Residual change in value 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Indication error % Meeting the requirements of 6.1
3 Vibration (sinusoidal) Variation of 50% of measuring range % 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Variation of lower range limit 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Variation of measuring range 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Residual change in value 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
4 Impact Variation of lower range limit % 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Variation of measuring range 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
5 Installation position Variation of lower range limit % 0.04 0.06 0.08 0.16
(0.20) 0.4 0.8 1.2
Variation of measuring range 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
6 Over range Variation of lower range limit % 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Variation of measuring range 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
7 Static pressure③④ Variation of zero point %/10 MPa 0.1 0.15 0.2 0.4
(0.5) 1.0 2.0 2.5
Variation of measuring range 0.1 0.15 0.2 0.4
(0.5) 1.0 2.0 2.5
8 Unidirectional static pressure③④ Variation of zero point % 0.1 0.15 0.2 0.4
(0.5) 1.0 2.0 2.5
Variation of measuring range 0.1 0.15 0.2 0.4
(0.5) 1.0 2.0 2.5
Measurement performance % Being tested after zero setting and meeting the requirements of 6.1~6.3
9 Accelerated service life Variation of lower range limit % 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Variation of measuring range 0.05 0.075 0.1 0.2
(0.25) 0.5 1.0 1.5
Notes:
1 If the indexes in the company standard of the pressure transmitter manufacturer are higher than those this program, they shall be subjected to the requirements of the company standard.
2 If the accuracy grade is inferior to Grade 0.2, items 2, 3, 4, 5 and 9 are optional.
3 If the requirements for the variations of lower range limit and measuring range of a same item are consistent, they can be simplified as an item index.
① The allowable values are expressed by the percentage of output measuring range.
② The influence of ambient temperature may be given by "%/10℃" or with other equivalent methods.
③ Static pressure and unidirectional static pressure may also be given in "%/MPa", "%/X MPa, X: static pressure value" or with other equivalent methods.
④ Static pressure and unidirectional are only applicable to differential pressure transmitter.
At the end of the test, a visual inspection shall be carried out to see whether any element or fitting is deformed or cracked, so as to verify whether the mechanical condition of the tested device is good.
7.9.4 Impact
The allowable values of the influence of impact on the lower range limit and measuring range of pressure transmitters may be selected from Table 2 according to their accuracy grades.
After the test, check whether the tested pressure transmitter is damaged.
7.9.5 Installation position
The allowable values of the influence of installation position on the lower range limit and measuring range of pressure transmitters may be selected from Table 2 according to their accuracy grades.
Note: For the pressure transmitter filled with liquid, the correction of the influence of liquid gravity on the lower limits shall be in accordance with the company standard.
7.9.6 Over range
The upper limit (multiple of full scale) of over-range test pressure that the pressure transmitter can bear shall be preferably selected from the following data: 1.25 times, 1.5 times, 2 times, 3 times, 5 times and 10 times.
The allowable values of the influence of over range on the lower range limit and measuring range of pressure transmitters may be selected from Table 2 according to their accuracy grades.
7.9.7 Static pressure (only applicable to differential pressure transmitter)
The static pressure (working pressure) of differential pressure transmitter shall be selected from the following data: 250 kPa, 400 kPa, 600 kPa, 1 MPa, 1.6 MPa, 2.5 MPa, 4 MPa, 6 MPa, 10 MPa, 14 MPa, 16 MPa, 25 MPa, 32 MPa, 40 MPa, 50 MPa and 64 MPa, or according to the specific technical requirements of products.
The allowable values of the influence of static pressure on the zero point and measuring range of differential pressure transmitters may be selected from Table 2 according to their accuracy grades.
Introduction i
1 Scope
2 Normative references
3 Terms and definitions
3.1 conformity
3.2 independent conformity
3.3 terminal-based conformity
3.4 zero-based conformity
3.5 residual change in value
3.6 step response time
3.7 dead band
4 General
5 Legal management requirements
5.1 Unit of measurement
5.2 Accuracy grade
5.3 Marking and identification
5.4 Requirements for external structure design
5.5 Technical documents and test prototypes provided for review
6 Measurement requirements
6.1 Indication error
6.2 Return difference
6.3 Repeatability
6.4 Terminal-based conformity
6.5 Dead band
7 General technical requirements
7.1 Normal working conditions
7.2 Reference working conditions
7.3 Functional characteristics
7.4 Appearance
7.5 Initial drift
7.6 Long-term drift
7.7 Frequency response
7.8 Step response
7.9 Items related to influence quantity
7.10 Items related to power input and electrical signal output
8 Table of pattern evaluation items
9 Test conditions and methods
9.1 Test conditions
9.2 Test apparatus
9.3 Test points
9.4 Indication error
9.5 Return difference
9.6 Repeatability
9.7 Terminal-based conformity
9.8 Dead band
9.9 Items related to functional characteristics
9.10 Appearance
9.11 Initial drift
9.12 Long-term drift
9.13 Frequency response
9.14 Step response
9.15 Items related to influence quantity
9.16 Items related to power input and electrical signal output
10 Judgment principle for pattern evaluation results
Annex A Original record format
