JB/T 7403-1994Illuminance meters (English PDF)

3.1 Product type

Illuminometers are divided into pointer illuminometers and digital illuminometers, according to their reading types.

3.2 Product grade

Product are divided into four grades: standard grade, first grade, second grade, third grade.

4.13 Electrical safety performance

The instrument shall comply with the requirements of JB 5517.

4.14 Storage and transportation environmental conditions

The instrument shall comply with the requirements of ZBY 002 under the conditions of storage, transportation, packaging. The high temperature test shall be +55 °C; the low temperature test shall be -40 °C; the free drop height shall be 250 mm.

5.1 Indication error (Article 4.1 of this standard)

5.1.1 Test device

a. One set of light intensity working reference lamps which have a color temperature of 2856K (used to measure the standard illuminometer);

b. One set of second grade light intensity standard lamps which have a color temperature of 2856K (used to measure first-, second-, third-grade illuminance meters);

c. DC voltage regulated power supply and corresponding supporting equipment (I.

Voltage regulated power supply requirements for light intensity working reference lamps: the voltage change shall not be greater than 0.015% and the […]

5.6 Fatigue error (Article 4.6 of this standard)

5.6.1 Test device

Same as Article 5.1.1 a ~ d of this standard.

5.6.2 Test procedure

Adjust the distance between the light source and the photometric probe on the photometric guide rail, so that the photometric probe can receive nearly 1000 lx illumination. Read out the indicated value of the illuminometer, when irradiating for 10 seconds. Then read out the indicated value of the illuminometer, when continuing irradiating for 30 minutes. Calculate the fatigue error according to formula (11):

Where:

Y(30 min) - The indicated value of the illuminometer when irradiated for 30 minutes, lx;

Y(10 s) - The indicated value of the illuminometer when irradiated for 10 seconds, lx;

f 5 - Fatigue error.

5.7 Nonlinear error (Article 4.7 of this standard)

5.7.1 Test device

Same as Article 5.1.1 a ~ d of this standard.

5.7.2 Test procedure

Adjust the distance between the light-emitting surface of the light source and the test surface of the photometric probe on the photometric guide rail. Find the standard illuminance value Xmax, which is corresponding to the full range of the illuminometer.

Meanwhile read out the indicated value Ymax of the illuminometer. Then move the photometric probe (or light source) to a position which is 1/10 of the full range.

Calculate the standard illuminance value X; read out the indicated value Y of the illuminometer. At least the nonlinear error of each gear below the l000 lx range shall be measured. Calculate the nonlinear error of each gear according to formula (12):

Where:

Y - The indicated value of the illuminometer at 1/10 full range, lx;

Ymax - The indicated value of the illuminometer at full range, lx;

X - The standard illuminance value at 1/10 full range, lx;

Xmax - The standard illuminance value at full range, lx;

f 6 - Linearity error.

5.8 Gear shift error (Article 4.8 of this standard)

5.8.1 Test device

Same as Article 5.1.1 a ~ d of this standard.

5.8.2 Test procedure

Adjust the distance from the light-emitting surface of the light source to the test surface of the photometric probe on the photometric guide rail. Find the standard illuminance value X (A) of the illuminometer, which is equivalent to that the illuminometer is at 90% of full range when it is at low range (gear A); meanwhile read out the indication value

Y (A) of the illuminometer. Then move the photometric probe (or light source) on the photometric guide rail, to the position where the standard illuminance value is K times higher than XA. Switch the illuminometer to gear B. Read out the indicated value Y(B).

Calculate the gear shift error according to formula (13):

Where:

5.11 Temperature coefficient (Article 4.11 of this standard)

5.11.1 Test device

a. Same as Article 5.1.1 a ~ c of this standard;

b. Temperature controller.

5.11.2 Test procedure

Place the illuminometer inside the temperature controller, with the indicator facing out the window. Place the standard lamp outside the temperature controller, to illuminate the photometric probe. Control the current of the standard lamp to remain constant and keep the relative position of the illuminometer and the light source constant. Control the temperature respectively at 5 °C, 20 °C, 40 °C, respectively. After maintaining temperature at each gear for one hour, read the indicated value of the illuminometer.

Then calculate according to formula (16).

Where:

T 1 - High temperature, which takes 40 °C;

T 2 - Low temperature, which takes 5 °C;

To - Normal temperature, which takes 20 °C;

Y(T 1 ) - The indicated value of the illuminometer at 40 °C, lx;

Y(T 2 ) - The indicated value of the illuminometer at 5 °C, lx;

Y(To) - The indicated value of the illuminometer at 20 °C, lx;

alpha - Temperature coefficient.

5.12 Instrument appearance and sensory requirements (Article 4.12 of this