EULUMDAT

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Example diagram from the software 1.0.1 QLumEdit

EULUMDAT is a format for the exchange of photometric data on the luminous intensity distribution of light sources. The typical file extension is * .ldt. The format was proposed by Axel Stockmar (Light Consult Inc., Berlin) in 1990 and has since developed into the industry standard for the transmission of photometric data in continental Europe. In the UK, by contrast, the TM14 format is preferred. In the American region, the IESNA LM-63 format exists parallel to the European standards .

features

EULUMDAT is a pure ASCII format where the data is organized line by line. The characters for the line break follow the convention under MS-DOS / Windows and consist of a carriage return (English: carriage return or <CR> ) and a line feed (English: line feed or <LF> ) in the order <CR> <LF >. Programs under operating systems with other conventions such as B. UNIX or Mac OS must take this into account so that the cross-platform exchange can work.

Since the file format only contains information about the light intensity, not the luminance , many properties of a light source cannot be transported in it. So z. B. Glare assessments can only be carried out using EULUMDAT if the light sources have a homogeneously radiant surface. However, this is not the case with many of today's lights, especially with light-emitting diodes or spotlights. A glare assessment is then not possible.

File format

EULUMDAT RECORD
Element
(line) 		description Number
of characters
1 Company name / database / version / format identification Max. 78
2 Light source type I type :
  • Point source with symmetry to the vertical axis = 1
  • Line source = 2
  • Point source with other symmetry = 3
    (only line sources , I type = 2, are divided into longitudinal and transverse directions)
 1
3 Type of symmetry I sym :
  • no symmetry = 0
  • Symmetry to the vertical axis = 1
  • Symmetry to plane C0-C180 = 2
  • Symmetry to plane C90-C270 = 3
  • Symmetry to the levels C0-C180 and C90-C270 = 4
 1
4th Number M c of C levels between 0 ° and 360 °
(usually 24 for indoor, 36 for street lighting) 		2
5 Angular interval D c between the C planes
(D c = 0 for non-equidistant C planes) 		5
6th Number N g of luminous intensity values ​​in each C-plane
(usually 19 or 37) 		2
7th Angular interval D g between the luminous intensity values ​​of a C-plane
(D g = 0 for non-equidistant luminous intensity values ​​in a C-plane) 		5
8th Measurement protocol number Max. 78
9 Luminaire designation Max. 78
10 Luminaire number Max. 78
11 File name / record name 8th
12 Date / user Max. 78
13 Length or diameter of the lamp in mm 4th
14th Width b of the light in millimeters
(b = 0 for circular light) 		4th
15th Height of the lamp in millimeters 4th
16 Length or diameter of the illuminated surface in millimeters 4th
17th Width b1 of the illuminated area in millimeters 4th
18th Height of the luminous surface in the C0 level in millimeters 4th
19th Height of the illuminated area in the C90 level in millimeters 4th
20th Height of the illuminated area in the C180 level in millimeters 4th
21st Height of the illuminated area in the C270 level in millimeters 4th
22nd Share of the lower semi-spatial luminous flux Phiu 4th
23 Luminaire efficiency in% 4th
24 Conversion factor for luminous intensity values
(depending on the measurement) 		6th
25th Inclination of the luminaire during the measurement
(street lighting) 		6th
26th Number n of standard lamp sets
(optional, expandable on a company -specific basis) 		4th
26a Number of lamps n * 4
26b Type of lamps n * 24
26c Total luminous flux of the lamps n * 12
26d Light color / color temperature n * 16
26e Color rendering class / color rendering index n * 6
26f Power consumption of the entire luminaire in W n * 8
27 Direct ratios for room indices k = 0.6 ... 5
(for determining the number of luminaires using the utilization factor method) 		10 * 7
28 C-angle (starting at 0 °) M c * 6
29 G angle (starting at 0 °) N g * 6
30th Luminous intensity distribution in candela per 1000 lumens
  • if I sym = 0 then M c 1 = 1 and M c 2 = M c
  • if I sym = 1, then M c 1 = 1 and M c 2 = 1
  • if I sym = 2, then M c 1 = 1 and M c 2 = M c / 2 + 1
  • if I sym = 3, then M c 1 = 3 * M c / 4 + 1 and M c 2 = M c 1 + M c / 2
  • if I sym = 4, then M c 1 = 1 and M c 2 = M c / 4 + 1
 (M c 2-M c 1 + 1) * N g * 6

literature

  • Ian Ashdown: Thinking Photometrically Part II. (Pdf; 1.2 MB) Version 1.05. In: LIGHTFAIR 2001 Pre-Conference Workshop. March 14, 2011, archived from the original on April 19, 2011 ; Retrieved April 19, 2011 (English).

Web links