Specifications：
Centric Rotating Mirror Goniophotometer （refer to CIE 70 -1987,
page 25）
1.Working theory of GO-CS centric moving mirror goniophotometers
The goniophotometer rotates the tested light source in the
prescribed burning position around the vertical axis and a
reflecting mirror rotates around the horizontal axis(Main axis). A
auxiliary axis will rotate toward the opposite direction
simultaneously. The combined motion of the luminaire and mirror
permit luminous measurement at the direction of any horizontal or
vertical angle without tilting the luminare and without disturbing
the luminous intensity during measurement.The photometer head is
located at a fixed position of the limiting photometric distance in
front of the reflecting mirror to gather the light in each
direction.
2.Technical characteristics
This kind of goniophotometer is also called Centric Rotating Mirror
Goniophotometer. It was widely applied in industry in the past 40
years. However, principle disadvantages are still unsolvable.
Since the tested light source has to move in a large space during
the measurement, the consequent problems list below will influence
the working stability of the tested light source:
1) It is the common sense that the temperature in upper space of a
darkroom is higher than the temperature in lower space,therefore,
the tested lighted source is working in alternating ambient
temperature. The higher is the darkroom, thebigger is the
difference between the temperature;
2) The moving arc in HID lamps will cut the geomagnetic field, and
this will affect the distribution of electric arc, thusaffect the
stability of the lamps;
3) The vibration and shock as well as the centripetal force due to
the circular motion of the tested light source areimpossible to
avoid; 4) The caused air flow will lead to great change of temperature in
the vicinity of the tested light source, andunfortunately, most
lamps and luminaries are sensitivity to their surface temperature.
5) The whole system can not work in fast measurement state,
otherwise, the above
described problems would be even more severe. The influence of these factor the measurement result vary with the
type of tested light sources.For most discharge lamps, the
measurement error caused by the unstability of the tested light
source is about 5% or mroe generally, in some serious cases, the
error could be 10% or more.
To realize the tested light source working both upwards and
downwards, the system requires even higher space on the
precondition that the distance between the test light source and
the mirror be large enough to reduce the stray light introduced by
their mutual reflectance, therefore, a higher darkroom is needed
for this system.
It is some difficult to achieve high angle accuracy due to the
problem of the synchronous rotation between the main axis and the
auxiliary. 3.Powerful measuring functions
Luminous intensity data, luminous intensity distribution curve,
efficient luminescence angle, spread angle, zonal luminous flux,
luminaires efficiency, total luminous flux, upper luminous flux,
lower luminous flux, available average illuminance curve,
coefficient of utilization, luminance limitation curves, glare,
maximum ratio of distance to height, iso-Illuminance diagrams,
curves of luminaires vs lighting area, Isocandela diagrams etc. 4. Date File Format:
1). *.GOSEVERFINE standard
2). *.CIECIE standard
3). *.CENCEN standard
4). *.IESIESNA standard
5). *.Tm14TM14 standard (Britain)
6). *.CIBCIBSE standard
7). *.EUTEULUMDAT standard (Germany)
The output file can directly match international Universal Lighting
Design Software, such as Dialux/AGI32/LumenMicro 5. Specifications：
Photometry
1). Accuracy of photometer head: Class L, f1'<1.5%/Class A,
f1'<3.0% (on request)
2). The detecting ability of photometer: 1×10-5/1×10-4 /1×10-3lx /
0.01lx. (on request)
3). Measuring Range of illuminance: 1×10-5/1×10-4 /0.001~20klx /
200klx (on requ |
