Yokogawa 51012 Digital Lux Meter, Simple Function Type The digital illuminance meter is a small, lightweight meter and enables illuminance measurements with the meter separated from the light detector. The display adopts a large liquid crystal display (LCD) for ease in reading, and attention is also paid to operation key arrangement. The photoelectric element adopts a silicon photo diode for correcting the spectral luminous efficiency by combining with an optical filter in order to measure the illuminance of natural light. There is a microcomputer incorporated in this meter to realize an illuminance meter having excellent functions. There are also various functions incorporated in this meter, not found in conventional meters: a data-hold function; a timer-hold function; deviation display; an automatic power-off function; a response selection function; and others. Refer to the text for details on these respective functions. Moreover, this illuminance meter provides recorder output and digital data output, further extending its usefulness. Thus, the range of applications of this meter is much more extensive than that of existing luxmeters (illuminance meters). This digital illuminance meter has been designed, manufactured, and delivered under strict quality control criteria by a factory certified in the ISO 9001 Quality Standards. We hope you will be able to make sufficient use of the performance of this product, in addition to our traditional photocell luxmeters.
Excellent characteristics (1) —-Visible region relative spectral response
The relative spectral response of the lux meter should ideally be the same degree of brightness as V(λ), which is the unit of brightness to which human beings are considered sensitive. In the JIS standard, the system of evaluating the characteristics of the visible region relative spectral response is adopted in order to bring the relative spectral response of the lux meter much closer to this ideal. The following diagram shows the relative spectral response (typical response) of the 510 series lux meter which conforms to this system.
Excellent characteristics (2) —-Oblique incident light
To measure the intensity of illumination from a light source in an oblique direction accurately, there is a necessity that the angle of incidence to the perpendicular line from the target of the surface is in proportion to the cosine law.
Color correction factor setting function
The 510 series lux meter measures the intensity of illumination more accurately because its sensitivity approximates to the standard spectral luminous ef ciency which is the same sensitivity as the human eye. However, since spectral characteristics differ depending on the light source types, a subtle indication error occurs. The 51021 lux meter incorporates a function to correct this error. (Factor xed: 8 types; arbitrary factor setting: 21 types).
Light source luminous intensity measurement function
The luminous intensity (candela) can be measured easily by setting the distance from the light source (0.01 to 99.99m).
Average illuminance computation function (correspondence to 4-point and 5-point methods)
This function automatically calculate 4 or 5 points average of illumination. JIS C 7612 [Illuminance Measurements for Lighting Installations] describes how to calculate the average illuminance using the 4-point and 5-point methods.
USB function (Power supply and communication)
With the USB interface, it can be used as a power supply source for continuous measuring with recorder output or/and USB communication.
|Product Includes||Instruction manual; dry cell (built in); soft case; recorder output plug|
|Specifications||Photoelectric element Silicon photodiode Display Liquid crystal display (number of 7 digits); maximum effective display:999; (0 or 0’s to indicate the number of digits) Measurement cycle Twice per second Measuring range 0.0 to 99.9/999/9,990/ 99,900/999,000lx Accuracy(*) ±4% rdg ±1dgt (under 3000lx) ±6% rdg ±1dgt (over 3000lx) Response time Automatic range : 5 sec; Manual range: 2 sec Characteristics of oblique incident light
Angle of :
10° ±1% 30° ±2% 50° ±6% 60° ±7% 80° ±25%
(deviation from cosine characteristics)
|size||67(W) x 177(H) x 38(D) mm|
|Power Supply||AA (LR6) x 2 OR USB supply (5 VDC ±5%)|
|Manufacturer Warranty||1 Year|