IESNA LM-72-1997 Directional Positioning of Photometric Data.pdf

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1、STD-IESNA IN-72-ENGL 1797 = L170L1580 0005030 37 U IESNA Guide Directional Positioning Photometric Data Prepared by The Angular Positioning Sub-Committee of IESNA Computer Committee the IESNA LM-72-97 IESNA Guide for Directional Positioning of Photometric Data Publication of this Committee Report ha

2、s been approved by the IESNA. Suggestions for revisions should be directed to the IESNA. Prepared by The Angular Positioning Sub-Committee of the IESNA Computer Committee ii IESNA LM-72-97 Copyright 1997 by the Illuminating Engineering Society of North America. Approved by the IESNA Board of Directo

3、rs, August 17, 1997, as a Transaction of the Illuminating Engineering Society of North America. All rights reserved. No part of this publication may be reproduced in any form, in any electronic retrieval sys- tem or otherwise, without prior written permission of the IESNA. Published by the Illuminat

4、ing Engineering Society of North America, 120 Wall Street, New York, New York 10005. IESNA Standards and Guides are developed through committee consensus and produced by the IESNA Office in New York. Careful attention is given to style and accuracy. If any errors are noted in this document, please f

5、orward them to Rita Harrold, Director Educational and Technical Development, at the above address for verifi- cation and correction. The IESNA welcomes and urges feedback and comments. Printed in the United States of America. iii STD-IESNA LM-72-ENGL 1777 Li7OLi580 0005033 5Yb m IESNA LM-72-97 Prepa

6、red by the Angular Positioning Sub-Committee of the IESNA Computer Committee Angular Positioning Sub-Committee Gregg A. Hauser, Chair D.L. DiLaura* P.K. Ericson P. Franck“ R.V. Heinisch J.D. Hibbs T.F. Saemisch Computer Committee Paul K. Ericson, Chair I. Ashdown W.S. Baker T.L. Ballman* G. Barber*

7、W. Brackett“ A. Cheng* R.B. Chong T.J. Dahlquist W. Dau* D.L. DiLaura* C.R. English* P. Franck* J.M. Freedman* J.B. Harvey G.A. Hauser R.V. Heinisch J.D. Hibbs D. Horrigan III* M.E. Keck R.M. King C.P. Latsis L. Livingston F.L. Locascio“ C.H. Loch G. Lowe* T. McGowan“ H.P. Powers W.C. Pursley T.F. S

8、aemisch R.A. Shakespeare D.C. Smith S.M. Stannard T. Terrill“ C.M. Troxell“ G.J. Ward C. E. Waters J. Zhang* *Advisory Member iv STD-IESNA LM-72-ENGL 1797 4704580 00051334 482 W IESNA LM-72-97 Contents Introduction 1 .O Photometry Systems 1,l Clockwise from North (CN) Positioning System 1.2 Counter

9、Clockwise from East (CCE) Positioning System 2.0 CN and CCE Positioning System Illustrations 3.0 Comments for Program Developers 4.0 Aiming a Luminaire at a Point References Annex A -Formulae for Aiming Systems Annex B-Overview of Goniometer Type A, B, and C V STD-IESNA LM-72-EFJGL 1577 8 4704580 00

10、05035 319 m IESNA LM-72-97 IESNA Guide for Directional Positioning of Photometric Data This document provides a clearly defined set of terms that can be used to designate the directional positioning of photometric data. The terms should be used by both providers and users of photometric data and lig

11、hting software to unambiguously and consistently specify how photometric data is to be “rotated“ before it is used Two similar but fundamentally irreconcilable angular positioning systems have existed for years. The Clockwise from North (CN) system starts by rotating luminaire photometrics clockwise

12、 from north. The Counter-Clockwise from East (CCE) system starts by rotating luminaire photometrics counter-clockwise from east. A third positioning method called “aiming a luminaire at a point“ has also existed for years and will also be discussed. Many early and current lighting programs use north

13、 as the starting point for luminaire orientation, with angles measured clockwise as on a compass. Specifiers who expected pole top installers to use compasses would often provide magnetic bearings as well. Users (designers, engineers, and steeplejacks) accustomed to these techniques would choose the

14、 CN system. Many computer aided design (CAD) programs and many related lighting programs use eastas the starting point for orientation, with angles measured counter- clockwise. Users (designers, engineers, draftsmen, physicists, and mathematicians) accustomed to these methods would select the CCE sy

15、stem. Designers of floodlighting, security and sports lighting often use the notion of “aiming a luminaire at a point,“ so most computer programs that handle floodlighting and sports lighting employ the “aiming at a point“ concept. For floodlighting and sports lighting work, aiming at a point is oft

16、en the most convenient approach to choose. Note that this document assigns specific, standard meanings to certain words, thus some users may need to adjust their vocabulary. Most should find a positioning system compatible with their normal patterns/experience. This document does not show a preferen

17、ce for any system, but rather describes each of the three systems and then explains how to convert between them. In applying CN or CCE, four types of angular “rotation“ are defined (Orientation, Tilt, Roll, and Spin) and each shall be performed in the defined order. Any (or all) of the rotation angl

18、es may be zero. Each subse- quent rotation is applied to the axis system as previ- ously rotated (the local axes), not the original axis system (the global axes). Orientation, Tilt, Roll, and Spin can be described using x, y, and z axes, but their implementation in the CN system and CCE system must

19、be described separately, and separate drawings of each coordi- nate system are needed. 1 .O PHOTOMETRY SYSTEMS Most photometry is available in a standard format in North America. Two types of photometry, which dif- fer in the orientation of the photometric web, have traditionally been used with that

20、 standard. Type C photometry2 is commonly used for indoor and roadway luminaires. Type B photometry45 has been used for adjustable floodlights. Refer to Annex B for a description of Type B and Type C photometry. Note: The figures discussed in Section 2.0 will assist in understanding the positioning

21、systems described in Section 1.1 and Section 1.2 which immediately follow. 1.1 Clockwise from North (CN) Positioning System The Clockwise from North (CN) angular positioning system is applicable to both Type B photometry and Type C photometry. With this system the initial posi- tion of photometric z

22、ero (horizontal angle = O“, verti- cal angle = 0) is straight down in the direction of the -z axis. To set the initial position of the luminaire pho- tometric grid in three-dimensional space, a second photometric direction must be established. The pho- tometric direction (Oo, go“), where the horizon

23、tal angle = O“ and the vertical angle = 90, is convenient for both Type B and Type C photometry. Initial photo- metric direction (O“, 90“) for the CN system is placed in the direction of the +y axis (north). First, Orientation is applied about the z axis, clock- wise looking in the direction of the

24、-z axis. Positive angles move the +y axis toward the +X axis. Orientation = O“ places the +y axis toward north. (Note: Initially, before any rotation is applied, the local and global coordinate systems are aligned). 1 STD-IESNA LM-72-ENGL 1797 q7Oq5BO 000503b 255 IESNA LM-72-97 Second, Tilt is appli

25、ed about the local x axis, clock- wise looking in the direction of the local +x axis. Positive angles move the local -z axis toward the local +y axis. (Moving the local +y axis toward the local +z axis is equivalent.) Third, Roll is applied about the local y axis, clockwise looking in the direction

26、of the local +y axis. Positive angles move the local -z axis toward the local -x axis. (Moving the local +z axis toward the local +x axis is equivalent.) Fourth, Spin is applied about the local z axis, clock- wise looking in the direction of the local -z axis of the luminaire photometrics. Positive

27、angles move the local +y axis toward the local +x axis. 1.2 Counter Clockwise from East (CCE) Positioning System The Counter Clockwise from East (CCE) angular positioning system is applicable to both Type B pho- tometry and Type C photometry. With this system, the initial position of photometric zer

28、o (horizontal angle = O“, vertical angle = O“) is straight down in the direc- tion of the -z axis. To set the initial position of the lumi- naire photometric grid in three-dimensional space, a second photometric direction must be established. The photometric direction (O“, goo), where the hori- zont

29、al angle = O“ and the vertical angle = go“, is con- venient for both Type B and Type C photometry. Initial photometric direction (O, 90) for the CCE system is placed in the direction of the +x axis (east). First, Orientation is applied about the z axis, counter- clockwise looking in the direction of

30、 the -z axis. Positive angles move the +x axis toward the +y axis. Orientation = O“ places the +x axis toward east. (Note: Initially, before any rotation is applied, the local and global coordinate systems are aligned). Second, Tilt is applied about the local y axis, clock- wise looking in the direc

31、tion of the local -y axis. Positive angles move the local -z axis toward the +x axis. (Moving the +x axis toward the local +z axis is equivalent). Third, Roll is applied about the local x axis, clockwise looking in the direction of the local +x axis. Positive angles move the local -z axis toward the

32、 local +y axis. Fourth, Spin is applied about the local z axis, counter- clockwise looking in the direction of the local -z axis. Positive angles move the local +x axis toward the local +y axis. 2.0 CN AND CCE POSITIONING SYSTEM ILLUSTRATIONS Figure 1 shows, for both the CN and CCE positioning syste

33、ms, each individual rotation. Each diagram shows the local axes and a luminaire (rectangular block) before the rotation. The arrow indicates the direction of positive rotation. The arrow length represents 90“. Figure 2 shows an example of (equivalent) angular positioning for each system. For the CN

34、system, the angles are: Orientation = go“, Tilt = 45“, Roll = go“, and Spin = 45“. For the CCE system, the angles are: Orientation = O“, Tilt = 45“, Roll = go“, and Spin = -45“. Each diagram shows the local axes and a luminaire (rectangular block) after the rotation is applied. Note that other sets

35、of four angles achieve the same position. For the CN system, Orientation = go“, Tilt = O“, Roll = go“, and Spin = O“ Suff ice. For the CCE system, Orientation = O“, Tilt = O“, Roll = go, and Spin = O“ suffice. 3.0 COMMENTS FOR PROGRAM All possible luminaire aiming positions can be achieved by omitti

36、ng oll or by omitting Spin. Historically, programs have been set up to use OrientationfliltlSpin or OrientationRilVoil (though often using different terminology). Either of these two systems are subsets of the Orientation/Ti/tloIl/Spin system defined in this document. All possible aiming positions c

37、an be achieved in the CN system and in the CCE system. The physical structure of some mounting mechanisms may make achieving certain aiming positions impossible. Program developers may choose to implement only one system and may choose to omit either Roll or Spin (as noted). The terms Orientation, T

38、ilt, oll, and Spin shall be used to specify luminaire photometric positioning only as defined here, in the order defined. The previous use of terms such as “rotation“ or “bearing“ for Orientation and “rotation“ or “cant“ for Roll is deprecated. Program developers are encouraged to let the user choos

39、e between using the CN system and the CCE system. Program developers are also encouraged to let the user enter all four rotation angles or to let the 2 STD-IESNA LM-72-ENGL 1777 LI7G4560 0005037 191 IESNA LM-72-97 CLOCKWISE FROM NORTH AIMING SYSTEM Local “I +Y /- % H=O V=W Local-z 1 H-O, WO hL-I Loc

40、al-2 H=O“, V=O ORIENTATION TILT ROLL COUNTER CLOCKWISE FROM EAST AIMING SYSTEM Local “I +Y I Local-2 I H=O, V=O hl “ +Y Local -2 H=O. V=O v=90* Local “1 +v SPIN H.0. V=W Figure 1. Positioning definitions for a luminaire (rectangular block) before rotation in the Clockwise from North aiming system (l

41、eft column) and the Counter Clockwise from East aiming system (right column). Each curved arrow indicates the direction of positive rotation, with the arrow length equal to 90“. 3 STD-IESNA LM-72-ENGL 1777 rn 1450 unci503 028 m IESNA LM-72-97 Local -2 CLOCKWISE FROM NORTH AIMING SYSTEM 90“ ORIENTATI

42、ON Local V=90 New Local -2 H4. V=O“ 45“ Local New Local Hx; -2 V=90* H=O New Local +Z Local -2 H=O“. V=O H=O“ V.90“ 90“ TILT ROLL COUNTER CLOCKWISE FROM EAST AIMING SYSTEM O“ Local Lq +Y Local +Y Local New Local -Z H=O. V=O 45“ I 90 Local -2 H=O“, V=O“ H=D“ V.900 Local Local +Z 45“ SPIN -45“ I +z Fi

43、gure 2. Equivalent positioning examples for a luminaire (rectangular block) after rotation in the Clockwise from North aiming system (left column) and the Counter Clockwise from East aiming system (right column). One corner of the luminaire is marked with the symbol “T“ to help the reader visualize

44、the positioning process. 4 - STD-IESNA LM-72-ENGL 1797 0 9704580 0005039 Tbll user choose which of the four rotation angles are to be entered. The order in which rotation angles are applied shall be fixed and cannot be changed. This standard is intended to be convenient for specifiers and for other

45、users. Almost all users can find a posi- tioning method compatible with their accustomed techniques. The advantage of adhering to a positioning standard is that ambiguity in rotation direction is removed and the specification of luminaire aiming is more reliable. Caution to users of any positioning

46、system: Positioning Type B photometry and asymmetrical Type C photometry requires careful checking of the pho- tometry and/or the results, since manufacturers and laboratories interpretations of the standards have var- ied. Luminaires such as wall-washers, sconces, step- lights, and in-wall uplights

47、 may produce unexpected results depending on the test position. For example, fluorescent wall-wash luminaires may have the O“ plane parallel to the lamps or the O“ plane may be per- pendicular to the lamps to represent the plane of sym- metry. The O“ plane may (or may not) contain higher candela val

48、ues than the 180 plane. Further, some wall-wash luminaires have higher candela values away from the wail rather than toward it. As another example, up-lights may have been tested with photometric zero being straight up rather than straight down. CLOCKWISE FROM NORTH AIMING SYSTEM New +Z H=O“ IESNA L

49、M-72-97 -y-*-%-i s. Ixxlbs-ip 4.0 AIMING A LUMINAIRE AT A POINT The “aiming a luminaire at a point“ positioning system is defined in this document as directing the nadir (local -z axis) from the luminaire photometric center to the aiming point, keeping the O“ plane vertical. Assuming this definition is met, Onentation and Tiit (as previously defined) are the only angles needed to duplicate a position achieved by “aiming a luminaire at a point.“ Other definitions of “aiming a luminaire at a point“ are deprecated. -y_w“w- -*-= - - No