PDF JJG 245-2005 English (JJG 245-1991: Older version)
Search result: JJG 245-2005 (JJG 245-1991 Older version)
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Name of Chinese Standard | Status |
| JJG 245-2005 | English | 620 |
Add to Cart
|
0-9 seconds. Auto-delivery.
|
Verification Regulation of Illuminance Meter
| Valid |
| JJG 245-1991 | English | 839 |
Add to Cart
|
6 days
|
Verification Regulation of Illuminometer
| Obsolete |
| JJG 245-1981 | English | RFQ |
ASK
|
3 days
|
(Chinese Industry Standard)
| Obsolete |
PDF Preview: JJG 245-2005
JJG 245-2005: PDF in English JJG 245-2005
JJG
METROLOGICAL VERIFICATION REGULATION
OF THE PEOPLE’S REPUBLIC OF CHINA
Illuminance meter
光照度计
ISSUED ON: APRIL 28, 2005
IMPLEMENTED ON: OCTOBER 10, 2005
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC.
Table of Contents
1 Scope ... 4
2 Normative references ... 4
3 Overview ... 4
4 Metering performance requirements ... 4
4.1 Relative indication error ... 4
4.2 V(λ) matching error ... 5
4.3 Cosine characteristic (directional response) error ... 5
4.4 Nonlinear error ... 5
4.5 Shift error ... 5
4.6 Fatigue error ... 6
4.7 Infrared response error ... 6
4.8 UV response error ... 6
4.9 Temperature coefficient ... 6
5 General technical requirements ... 7
5.1 Appearance ... 7
5.2 Identification ... 7
5.3 Instructions ... 7
6 Metering instrument control ... 7
6.1 Verification conditions ... 7
6.2 Verification items ... 8
6.3 Verification method ... 9
6.4 Processing of verification results ... 13
6.5 Verification cycle ... 14
Appendix A Recommended test methods for type identification and prototype testing
... 15
Appendix B Verification of illuminance meter using comparison method ... 20
Appendix C Example of uncertainty assessment ... 22
Appendix D The relationship between the two formulas of cosine characteristic error
... 28
Appendix E Format of the inner page of the illuminance meter's verification certificate
and verification result notification ... 30
Verification regulation of illuminance meter
1 Scope
This Regulation applies to the initial verification, subsequent verification, in-use
inspection of illuminance meters (hereinafter referred to as illuminance meters). The
requirements related to measurement performance in type identification and prototype
testing can be implemented with reference to Regulation.
2 Normative references
This Regulation cites the following documents:
"Illuminance Meter" OIML 1988 English version
"Performance Test Methods for Photometers and Luminometers" CIE 1987 English
version
JJF 1059-1999 "Evaluation and Expression of Uncertainty in Measurement"
When using this Regulation, attention shall be paid to using the currently valid versions
of the above cited documents.
3 Overview
An illuminance meter is a measuring instrument for measuring illuminance. It consists
of a photometric probe (including a cosine corrector, a V (λ) correction filter, a
photoelectric receiver) and a display (digital or pointer type). When the photoelectric
receiver receives the optical radiation passing through the cosine corrector and V(λ)
filter, the generated photoelectric signal is processed and the corresponding illumination
value is displayed on the display.
4 Metering performance requirements
4.1 Relative indication error
The relative indication error of the illuminance meter shall not exceed the requirements
of Table 1.
l - The distance from the filament plane of the standard lamp to the test surface of
the photometric probe, m.
During verification, the distance -- between the filament plane of the standard lamp and
the photometric probe must be at least 15 times greater than the maximum linear
dimension of the light-emitting surface or the test surface of the photometric probe (the
diagonal length or diameter of the filament plane and the test surface of the photometric
probe).
The standard illuminance meter shall calibrate at least five equally spaced points, within
the full range of each gear. The level 1 and level 2 illuminance meters shall calibrate at
least three equally spaced points. Each point shall be illuminated for 5 seconds and its
display value shall be read. Each instrument is required to be verified for two rounds.
The relative deviation of the two rounds of values: standard, level 1, level 2 illuminance
meters shall not exceed 0.6%, 1%, 1.5%, respectively. The average value of each point
is taken as the final result. The relative indication errors of illuminance meters at all
levels shall comply with the requirements of 4.1.
Relative indication error = [(Displayed value - standard value) / Standard value] × 100%
(2)
For level 1 and level 2 illuminance meters, the comparison method can also be used for
verification. See Appendix B for the method.
6.3.3 Cosine characteristic (directional response) error of illuminance meter
6.3.3.1 Install the photometric probe on the rotating platform with the dial of the
photometric measuring device, so that the rotation axis of the platform passes through
the center line of the test surface. Adjust the filament plane of the standard lamp and
the test surface of the photometric probe, so that they are perpendicular to the horizontal
measurement axis of the light track, with the center point located on this axis. Arrange
a number of diaphragms between the standard lamp and the photometric probe. The
distance from the standard lamp to the photometric probe shall be at least 15 times the
maximum linearity of the luminous surface of the standard lamp or the test surface of
the photometric probe.
Figure 1 -- Schematic diagram of calibrating the illuminance meter on the
photometric measuring device
Calculate the total directional error f2 of the optical probe according to formula (4):
Where:
1.484 rad is equal to 85°.
The directional response error of illuminance meters at all levels shall comply with the
requirements of 4.3.
The derivation relationship between formula (3) and formula (4) can be found in
Appendix D.
6.3.4 Nonlinear error
6.3.4.1 On the photometric measuring device, install the standard lamp and the
photometric probe of the illuminance meter in accordance with the requirements for
calibrating the illuminance meter. The position of the fixed photometric probe remains
unchanged; the standard lamp is moved so that the display value Y of the illuminance
meter reaches 1/10 of the full scale; its corresponding standard illuminance value is X.
Then move the standard lamp to make the display value of the illuminance meter reach
Ymax (close to full scale). Find the corresponding standard illuminance value Xmax.
6.3.4.2 Calculate the nonlinear error f3 of the photometer according to formula (5):
Where:
X - Standard illumination value;
Y - Display value when the standard illumination value X illuminates the photometer
probe;
Xmax - The standard illumination value corresponding to the maximum display value
Ymax;
Ymax - Maximum display value.
The nonlinear errors of illuminance meters at all levels shall comply with the
requirements of 4.4.
6.3.5 Shift error
6.3.5.1 On the photometric measuring device, install the standard lamp and the
photometric probe of the illuminance meter in accordance with the requirements for
calibrating the illuminance meter. Keep the position of the fixed photometric probe
unchanged; move the standard lamp, so that the standard illumination value X (A)
reaches 90% of the full scale in the low-range gear A; its displayed value is Y (A). Then
change the illuminance meter to the relatively high range B; move the standard lamp so
that the standard illuminance value X (B) increases k times compared to X (A). Read
the illuminance meter's display value Y (B).
6.3.5.2 Calculate the error f4 caused by the change of measuring range according to
formula (6):
Where:
Y(A) - The display value of the standard illumination value X (A) (equivalent to 90%
of the full scale) in the range A gear;
Y(B) - The display value of X (B) that is k times higher than X (A) in the relatively
high range B gear;
k - Shift multiple, k = Y (full-scale reading of range B gear) / Y (full-scale reading
of range A gear).
The shifting error of illuminance meters at all levels shall comply with the requirements
of 4.5.
6.4 Processing of verification results
Carry out verification one by one according to the provisions of 6.2 "Verification items".
Record the various data obtained. Calculate the results. If all items meet the
requirements of this Regulation, it will be judged as qualified (for ungraded illuminance
meters, a verification conclusion can be issued that "the verified items meet the
requirements of a certain level of illuminance meter"); otherwise, it will be unqualified.
For qualified instruments, a calibration certificate will be issued; for unqualified
instruments, a calibration result notification will be issued. Please refer to Appendix E
for the format of the inner pages.
Newly produced illuminance meters shall be subject to initial verification. After repair,
some necessary verification items can be added to the repaired illuminance meter
according to the repair situation. During the initial verification, based on the verification
data results and the description of the measurement performance indicators in the
instrument's instruction manual, in accordance with the relevant provisions in Chapter
4 of this Regulation, the instrument will be graded and a calibration certificate will be
Appendix A
Recommended test methods for type identification and prototype testing
Type identification and prototype testing shall be carried out in accordance with JJF
1015-2002 "General norm for pattern evaluation and pattern approval of measuring
instruments" and JJF 1016-2002 "The rules for drafting program of pattern evaluation
of measuring instruments". The test items include appearance, relative indication error,
V (λ) Matching error, cosine characteristic error, nonlinear error, shift error, fatigue
error, infrared response error, ultraviolet response error, temperature coefficient. This
Appendix only gives the test methods other than 6.3 for type identification and
prototype testing.
A.1 V(λ) matching error of illuminance meter
The photometric probe of the illuminance meter must have a V (λ) filter, so that its
spectral responsivity matches the CIE photopic spectral efficiency of the International
Commission on Illumination. The matching error f1 is calculated as follows:
Where:
S* (λ)rel - Standardized (normalized) relative spectral responsivity.
Where:
PA(λ) - Relative spectral power distribution of 2856 K light source;
S(λ)rel - The relative spectral responsivity using any reference point as the standard;
V(λ) - CIE photopic spectrum light efficiency.
The V(λ) matching error of illuminance meters at all levels shall meet the requirements
of 4.2.
Appendix B
Verification of illuminance meter using comparison method
B.1 Illuminance meter calibration device
The illuminance meter's calibration device is shown in Figure A.1. It consists of two
parts: an integrating sphere and a camera obscura. The integrating sphere part includes:
2856 K light source, integrating sphere, adjustable diaphragm; camera obscura includes:
light track, movable turntable, photometric probe fixture, camera obscura, etc.
Figure B.1 -- Illuminance meter's calibration device
1 - Camera obscura; 2 - Slide rail; 3 - Mobile turntable; 4 - Standard illuminance meter's
photometric probe fixture; 5 - Photometric probe fixture of the illuminance meter under
test; 6 - Adjustable diaphragm; 7 - Integrating sphere (contains 2856 K light source)
B.2 Verification method
Install the qualified standard illuminance meter and the photometric probe of the tested
illuminance meter, respectively, on the workbench fixture of the illuminance meter
calibration device. Adjust the test surfaces of the two photometric probes, so that the
distances between them and the adjustable aperture are equal. Point the photometric
probe of the illuminance meter under inspection toward the integrating sphere. Move
the position of the workbench. Change the distance between the test surface and the
adjustable diaphragm. Or change the size of the adjustable diaphragm, so that the
display value of the illuminance meter is a certain reading. Then rotate the workbench
180°, so that the photometric probe of the standard illuminance meter faces the
integrating sphere. At this time, the value measured by the standard illuminance meter
is the actual illuminance value of one of the above readings of the tested illuminance
meter.
The illuminance meter must calibrate at least three equally spaced points within the full
range of each gear. Each instrument is required to be verified for two rounds. The
relative deviation of the two rounds of values: the level 1 and level 2 illuminance meters
shall not exceed 1% and 1.5%, respectively. The average of each point is taken as the
Appendix C
Example of uncertainty assessment
This Appendix only provides an example analysis for the assessment of the uncertainty
of the measurement results of the indication error, when using a level 1 standard lamp
to verify one indication value of the level 1 and level 2 illuminance meters (the standard
illuminance value is 100 lx). In actual work, the maximum value of the uncertainty of
the measurement results can be given or the uncertainty can be evaluated point by point
(range by range) according to customer requirements.
C.1 Measurement method
According to the relevant steps specified in this Regulation, install a 2856 K luminous
intensity level 1 standard lamp and the illuminance meter to be verified on the
photometric measurement device. Adjust their positions. Change the distance between
the standard lamp and the photometric probe. Read the display value of the illuminance
meter at the measurement point. Conduct two rounds of experiments. Take the average
as the final result.
C.2 Mathematical model
C.2.1 Establish mathematical model:
Where:
ΔE - The indication error of the illuminance meter under verification;
- The average value displayed by the illuminance meter under verification;
I(i) - The luminous intensity of the standard lamp, I(i) = 1180 cd;
i - The current supplied to the standard lamp, i = 6.7024 A;
l - The distance from the filament plane of the standard lamp to the test surface of
the photometric probe, l = 3.435 m.
C.2.2 Sensitivity coefficient:
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
Similar standards: JJG 178 JJG 810 JJG 452
|