IES standard file formats can be created and
modified.
You can create a photometric data file in the IES format using
the IES LM-63-1991 standard file format for photometric data. (IES
stands for Illuminating Engineering Society.) However, only the
information relevant to AutoCAD is described here. For a complete
description of the IES standard file format, see IES Standard File
Format for Electronic Transfer of Photometric Data and Related
Information, prepared by the IES Computer Committee (http://www.iesna.org).
The luminous intensity distribution (LID) of a luminaire is
measured at the nodes of a photometric web for a fixed set of
horizontal and vertical angles. The poles of the web lie along the
vertical axis, with the nadir corresponding to a vertical angle of
zero degrees. The horizontal axis corresponds to a horizontal angle
of zero degrees and is oriented parallel to the length of the
luminaire. This type of photometric web is generated by a Type C
goniometer and is the most popular in North America; other types of
goniometry are supported by the IES standard file format but are
not discussed here.
The photometric data is stored in an ASCII file. Each line in
the file must be less than 132 characters long and must be
terminated by a carriage return/line-feed character sequence.
Longer lines can be continued by inserting a carriage
return/line-feed character sequence.
Each field in
the file must begin on a new line and must appear exactly in the
following sequence:
IESNA91
[TEST] The test report number of your data
[MANUFAC] The manufacturer of the luminaire
TILT=NONE
1
The initial rated lumens for the lamp used in the test or -1 if
absolute photometry is used and the intensity values do not depend
on different lamp ratings.
A multiplying factor for all the candela values in the file.
This makes it possible to easily scale all the candela values in
the file when the measuring device operates in unusual units—for
example, when you obtain the photometric values from a catalog
using a ruler on a goniometric diagram. Normally the multiplying
factor is 1.
The number of vertical angles in the photometric web.
The number of horizontal angles in the photometric web.
1
The type of unit used to measure the dimensions of the luminous
opening. Use 1 for feet or 2 for meters.
The width, length, and height of the luminous opening. It is
normally given as 0 0 0.
1.0 1.0 0.0
The set of vertical angles, listed in increasing order. If the
distribution lies completely in the bottom hemisphere, the first
and last angles must be 00 and 900, respectively. If the
distribution lies completely in the top hemisphere, the first and
last angles must be 900 and 1800, respectively. Otherwise, they
must be 00 and 1800, respectively.
The set of horizontal angles, listed in increasing order. The
first angle must be 00. The last angle determines the degree of
lateral symmetry displayed by the intensity distribution. If it is
00, the distribution is axially symmetric. If it is 900, the
distribution is symmetric in each quadrant. If it is 1800, the
distribution is symmetric about a vertical plane. If it is greater
than 1800 and less than or equal to 3600, the distribution exhibits
no lateral symmetries. All other values are invalid.
The set of candela values. First, all the candela values
corresponding to the first horizontal angle are listed, starting
with the value corresponding to the smallest vertical angle and
moving up the associated vertical plane. Then, the candela values
corresponding to the vertical plane through the second horizontal
angle are listed, and so on until the last horizontal angle. Each
vertical slice of values must start on a new line. Long lines may
be broken between values as needed by following the instructions
given earlier.
Example of
Photometric Data File
The following is an example of a photometric data file.
