AS 4852.2:2019 pdf free
AS 4852.2:2019 pdf free.Variable message signs
Production signs will normally be too large to allow optical testing in the laboratory. For this reason,test modules for all laboratory testing and certification shall be provided. The VMS test module shall be an exact replica of the original equipment in that it shall perform photometrically and colorimetrically in an identical way to the original. It shall include the viewing window of the sign.
All tests and measurements shall be made at an ambient temperature of 25 °C±2 °C with a photo detector and measuring unit that is stable in operation and not subject to fatigue when exposed to the maximum level of luminance. The combination of detector and measuring unit in all ranges shall have a linear response to light up to the maximum level of luminance. The spectral responsivity of the detector shall closely follow the CIE spectral luminous efficiency function for photopic vision V(2).
The illuminance or luminance meter, used for the photometric measurements, shall be characterized according to ISO/CIE 19476.
The solar simulator source shall have spectral content close to that of natural daylight and a colour temperature of between 5000 K and 6000 K. The solar simulator source in conjunction with an optical attenuation device shall be capable of achieving levels of illuminance between 40000 lx and 4 lx, which shall be uniform (+10 % of the nominal value) over the area of measurement.
The measurement configuration of the sign, solar simulator source and photometer shall be arranged in accordance with Figure A.1. The photometer shall be positioned on the geometric axis of the sign (the reference axis). The solar simulator source axis shall be either vertically above or vertically below the reference axis. The following angular restrictions apply:
(a) The angle axis between the solar simulator source axis and the reference axis shall be 10.0°±0.1°.
(b) The angular subtense of the measurement test area (see Clause A.3) as viewed from the photometer shall be≤3°.AS 4852.2 pdf free download.
