The photometry service is provided through a special laboratory equipped with sophisticated equipment able to perform this service as specified below.
PHOTOGLOBE 4FA SIMPLIFIED
The Photoglobe 4FA SEMPLIFICATO photogoniometer is classified as:
type 4 according to EN 13032-1
type C according to IES regulation LM-79-08
the light source is fixed for the entire duration of the measurement and can be mounted in any operating position;
the photometer moves on the surface of a virtual sphere, whose center coincides with the photometric center of the light source;
the measurement of the distribution of light intensity is generally carried out by means of a continuous movement in spherical zones (parallel to the equator) or in spherical segments (from pole to pole).
Photoglobe 4FA SIMPLIFIED is composed of an arched structure, made of aluminum, moved by a stepper motor that makes it rotate around the virtual axis that starts from the photometric center of the illuminator. The illuminator is positioned at the front of the arc and remains fixed during the photometric measurement. The aluminum probe-holder structure rotates in a solid manner with the optical axis of the projector whose photometric curves are to be detected.
On this rotating structure, with a quarter of a circumference, 10 probes are placed (each probe represents a specific angle of the "Gamma" plane) that are acquired simultaneously.
A hardware interface and a powerful management software allow the acquisition and processing of measurement values, via computer, in a completely automated way.
Acquisition group (probes)
The system is inclusive of 10 probes for the acquisition along the corners of the gamma plane arranged on an arched structure (90 ° degrees), with a radius of 1350 mm.
The individual probes have the following characteristics:
|measuring range||0-300000 lux|
|measurement uncertainty||< 1 %|
|total performance||Class L (total error <3%) for laboratory use|
To have a smaller deviation compared to V (λ) the system provides two types of calibrations: one for LED and one for all other sources ("non-LED").
It will be sufficient for the operator to choose the type of measurement to be performed, using the corresponding command in the software.
An optical system, integrated into the probes, moves the image of the source away making it point-like.
In this way, the requirement of the UNI EN 13032-1 and IES LM-79-08 standards in terms of the relationship between the measurement distance and the maximum size of the light emitting surface of the luminaire is fully satisfied.
Analog digital converter
Thanks to a sophisticated support electronics, the 10 probes connect to the computer through an analogue digital converter.
The probe support is an arched structure (quarter circle, ie covering an angle of 90 °) with a radius of 1350 mm. The probes are placed on the structure in the inner part of the arc so that the perpendicular to the surfaces of the probes themselves intersect in the center of the arc where the photometric center of the lamp to be measured is placed.
For the illumination centering procedure, the probe holder is equipped with two laser pointers, one above the 0 ° probe and the other above the 90 ° probe, whose beams are perfectly aligned with the photometric planes. The point of intersection of these two beams must coincide with the photometric center of the illuminator.
At the 0 ° angle of the Gamma plane, the arc is connected to a stepper motor that turns the structure, in computer-driven steps, around an axis that coincides with the optical axis of the lamp to be measured. in the fulcrum of the arch itself. The structure and the rotation speed of the probe support have been designed to minimize vibrations when the system is being measured.
Electronics for controlling and controlling the movement of the engine
The motor control board is a control board with a dedicated firmware that allows the motor to communicate with the computer. It is able to translate the movement and data speed commands from the computer to the motor and to check the movement performed so that they can be read by the computer itself.
Features of mechanical movement of the arm:
- rotating arm (quarter circle) in black aluminum, rotation in azimuth +/- 180 °;
- precision: concentricity 0.0015 mm;
- minimum angular step that can be imposed remotely (Plan C) 0.1 °;
- mechanical availability: 0.006 °;
- accuracy: 0.01 °;
- control and movement of the axis (rotation) n. 1 stepper motor;
- arm radius: 1350 mm;
- acquisition time: coordinate detection by the stop goniometer control <of 0.3 seconds.
- absolute measurement (when, in order to normalize the values obtained as a result of the measurement, to convert the lux into cd / klm, the flow exiting the device will be used, this flow is calculated by the software according to the UNI 11356 standard);
Relative measurement (when, in order to normalize the values obtained as a result of the measurement, ie to convert the lux into cd / klm, the nominal flow of the source, known as a result of a flow measurement or declared by the source manufacturer, is used; manually, at the beginning of the measurement).
EXAMPLE OF PHOTOMETRY REPORT
Protractoraccuracy of rotation contained in 0.1º, 19 probes able to measure simultaneously the respective photometric values and transfer them to the computer
Photometric probesvery high precision probes with a dynamic range of 0-80,000 Lux, accuracy of ± 0.01 Lux, filtered V (λ) with a deviation from the theoretical curve ≤ ± 1%
Management and control softwareacquisition according to C-Gamma plans and visualization of photometric curves in real time