JJG 376-2007_English: PDF (JJG376-2007)
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Verification Regulation of Electrolytic Conductivity Meters
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JJG 376-2007
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Standards related to: JJG 376-2007
| Standard ID | JJG 376-2007 (JJG376-2007) | | Description (Translated English) | Verification Regulation of Electrolytic Conductivity Meters | | Sector / Industry | Metrology & Measurement Industry Standard | | Classification of Chinese Standard | A55 | | Classification of International Standard | 17.220 | | Word Count Estimation | 17,120 | | Date of Issue | 2007-11-21 | | Date of Implementation | 2008-05-21 | | Older Standard (superseded by this standard) | JJG 376-1985 | | Quoted Standard | OIML R68; BS EN 60746-3-2002 | | Drafting Organization | China Institute of Metrology | | Administrative Organization | National Technical Committee of Physics stoichiometric measurement | | Regulation (derived from) | AQSIQ Announcement No. 188 of 2007 | | Issuing agency(ies) | State Administration of Quality Supervision, Inspection and Quarantine | | Summary | This standard applies to the electrolyte conductivity meter for initial verification, testing and use of follow-up inspection. Resistivity meter and conductivity measurement principle based on salinity and total dissolved solids meter measuring instrument calibration can be implemented by reference. | JJG 376-2007
JJG
National Metrological Verification Procedures
of the People's Republic of China
Electrolytic Conductivity Meters
ISSUED ON. NOVEMBER 21, 2007
IMPLEMENTED ON. MAY 21, 2008
Issued by. State Administration of Quality Supervision, Inspection and
Quarantine
Verification Regulation of
Electrolytic Conductivity Meters
This regulation was approved by the State Administration of Quality Supervision,
Inspection and Quarantine on November 21, 2007, and was put into effect on May 21,
2008.
Administrative organization. National Physical and Chemical Metrology Technical
Committee
Drafting organization. China Institute of Metrology
This regulation entrusts the National Physical and Chemical Metrology Technical
Committee for interpretation
Main drafter of this regulation.
Xiaoping Song (China Institute of Metrology)
Participating drafters.
Kan Ying (China Institute of Metrology)
Wang Hai (China Institute of Metrology)
JJG 376-2007 Corrigendum
Page 3 Row 8, Column 6 in Table 1. The value “±0.2” shall be “±2.0”.
Page 4 Penultimate line 4. The value “0.25” shall be “0.25%”.
Replacing JJG 376-1985
Table of Contents
1 Scope ... 4
2 Normative references ... 4
3 Terminology and measuring unit ... 4
4 Overview ... 6
5 Measuring performance requirements ... 6
5.1 The electronic unit repeatability ... 6
5.2 Electronic unit cited error ... 6
5.3 Indication error of conductance cell’s constant ... 6
5.4 Indication error of temperature coefficient ... 6
5.5 Indication error of temperature measurement ... 6
5.6 Instrument cited error ... 6
5.7 Repetitiveness of Instrument ... 7
6 General technical requirements ... 7
7 Control of measuring instruments... 7
7.1 Verification conditions ... 7
7.2 Verification items ... 9
7.3 Verification method ... 9
7.4 Processing of verification results ... 14
7.5 Verification period ... 14
Appendix A Conductivity standard solution concentration and its conductivity
value ... 15
Appendix B Example of electrolytic conductivity meter calibration record ... 16
Appendix C Example of inner page format of verification certificate ... 21
Verification Regulation of Electrolytic Conductivity Meters
1 Scope
This regulation applies to the first-time verification, subsequent verification, and in-use
inspection of electrolytic conductivity meters. Calibration of resistivity meter, salinity meter
based on the electrical conductivity measurement principle, and TDS measurement
instrument can reference to this regulation.
2 Normative references
OIML R68 Edition 1985 Calibration method for conductivity cell
BS EN 60746-3.2002 Expression of performance of electrochemical analyzers - Part 3.
Electrolytic conductivity
3 Terminology and measuring unit
3.1 Electrolytic conductance
The ratio of current and electric potential difference when ionic charge of conductivity cell
moves in the electrolyte solution.
Where.
G — conductance, S;
I — current through the electrolyte solution, A;
U — Electric potential difference between the electrodes, V.
Resistance is the reciprocal of conductance, unit is Ω.
3.2 Electrolytic conductivity of the electrolyte solution
Conductivity of electrolytic solution is defined by the following formula.
Where.
k — Electrical conductivity, S·m-1;
4 Overview
Conductivity meter is used to measure the electrolyte solution conductivity. The
measuring principle of conductivity meter is based on the relationship [formula (4)] of
conductivity, electric conductance, and conductance cell’s constant. Apply
alternating electrical signals between electrodes of conductance cell to measure the
solution conductivity; obtain the conductivity according to the imputed conductance cell’s
constant.
Conductivity meter is mainly consisted of two parts - the electronic unit and the sensor unit.
Electronic unit usually includes signal generator, measuring unit (alternating current
bridge or proportional amplifier), detector and reading part, as well as the unit for
conductance cell’s constant adjustment, temperature compensation and temperature
measurement function. Sensor unit mainly includes conductance cell, generally it also
includes a temperature sensor which is used for electrical signal transmission between
the solution and electronic unit, and to measure the temperature of the solution.
Verification of conductivity meters includes 2 parts - electronic unit verification and
instrument verification. This regulation divides the conductivity meters into 8 levels - 0.2,
0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 4.0, according to verification results of cited error of
electronic unit. The metrological performance of each level is shown in Table 1.
5 Measuring performance requirements
5.1 The electronic unit repeatability
Verification results shall comply with the provisions of Table 1.
5.2 Electronic unit cited error
Verification results shall comply with the provisions of Table 1.
5.3 Indication error of conductance cell’s constant
Verification results shall comply with the provisions of Table 1.
5.4 Indication error of temperature coefficient
Verification results shall comply with the provisions of Table 1.
5.5 Indication error of temperature measurement
Verification results shall comply with the provisions of Table 1.
5.6 Instrument cited error
Verification results shall comply with the provisions of Table 1.
7.3.5 Indication error of temperature coefficient
1) According to Figure 1. Connect to any standard conductivity Gs (for example 100uS) on
the medium range. Place the constant adjustor at KcellR (usually 1.000 cm-1).
Temperature coefficient is set to 0.00% or "no compensation"; or adjust the
temperature indication value to be instrument reference value TR (usually 25 °C). Read
the electrolytic conductivity meter’s measurement value KMR.
2) Set temperature coefficient α = 2.00%·°C-1. Adjust the temperature sensor simulation
resistance. Make temperature indication value as T = 15 °C. Read the electrolytic
conductivity meter’s measurement value KMR. Calculate the indication error of
temperature coefficient according to Formula (9).
3) Adjust the temperature sensor simulation resistance. Make the temperature indication
value as T = 35 °C. Operate according to step 2), calculate the indication error of
temperature coefficient.
4) Set the temperature coefficient α = 1.50%·°C-1. Repeat steps 2 and 3).
5) Set the temperature coefficient α = 2.50%·°C-1. Repeat steps 2 and 3).
If the electrolytic conductivity meter has no temperature compensation function, this item
may be exempted.
Notes. 4) and 5) are the required operation for first-time verification of instrument.
7.3.6 Indication error of temperature
1) Connect the electrolytic conductivity meter with electronic unit of temperature sensor.
Place it in the same thermostatic bath with standard thermometer. Standard
thermometer and temperature sensor shall be as close as possible.
2) Control the thermostatic bath’s temperature to be the instrument’s reference
temperature TR (usually 25 °C). At the same time, read standard thermometer
measurement value TS and electrolytic conductivity meter’s temperature
measurement value TM. Calculate the indication error of temperature of single
measurement according to Formula (10).
3) According to the step 2), repeat for 3 times. Calculate the arithmetic mean of
indication error of 3-times temperature to be the indication error of instrument
temperature measurement.
IV. Conclusion.
According to the verification results, this instrument conforms to 0.5-level.
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