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Contents Page

Foreword ............................................................................................................................................................ iv

Introduct ion .........................................................................................................................................................v

1 Scope ......................................................................................................................................................1

2 Normative References...........................................................................................................................1

3 Terms and Defini tions ...........................................................................................................................2

4 Symbols ..................................................................................................................................................3

5 Environmental and metrological requi rements..................................................................................45.1 Environmental condi tions ....................................................................................................................45.2 Operat ing condit ions ............................................................................................................................4

5.3 Length measurement error,EL .............................................................................................................45.4 Probing form error, PF ...........................................................................................................................55.5 Probing size error, PS ............................................................................................................................55.6 Probing location error, PL .....................................................................................................................5

6 Acceptance tests and reveri fication tests ..........................................................................................56.1 General ...................................................................................................................................................56.2 Probe erro rs ...........................................................................................................................................66.2.1 Principle..................................................................................................................................................66.2.2 Measur ing equipment ...........................................................................................................................66.2.3 Procedure...............................................................................................................................................66.2.4 Derivation of test results ......................................................................................................................76.3 Probing location errors (two-face tests) .............................................................................................86.3.1 Principle..................................................................................................................................................86.3.2 Measur ing equipment ...........................................................................................................................86.3.3 Procedure...............................................................................................................................................86.3.4 Derivation of test results ......................................................................................................................96.4 Length errors .........................................................................................................................................96.4.1 Principle..................................................................................................................................................96.4.2 Measur ing equipment ...........................................................................................................................96.4.3 Procedure.............................................................................................................................................106.4.4 Derivation of test results ....................................................................................................................15

7 Compliance wi th specif ication ...........................................................................................................167.1 Acceptance tests .................................................................................................................................167.2 Reveri fi cat ion tests .............................................................................................................................16

8 Applications .........................................................................................................................................16

8.1 Acceptance test ...................................................................................................................................168.2 Reveri fi cation test ...............................................................................................................................178.3 Interim check........................................................................................................................................17

9 Indication in product documentation and data sheets ....................................................................17

Annex A (normative) FORMS ..........................................................................................................................19

Annex B (normative) Calibrated Test Lengths .............................................................................................21

Annex C (normative) THERMAL COMPENSATION OF WORKPIECES .......................................................22

Annex D (informative) ACHIEVING THE ALTERNATIVE MEASURING VOLUME.......................................23

Annex E (informative) INTERIM TESTING......................................................................................................25

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iv ISO 2010 All rights reserved

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies(ISO member bodies). The work of preparing International Standards is normally carried out through ISOtechnical committees. Each member body interested in a subject for which a technical committee has beenestablished has the right to be represented on that committee. International organizations, governmental andnon-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with theInternational Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standardsadopted by the technical committees are circulated to the member bodies for voting. Publication as anInternational Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patentrights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 10360-10 was prepared by Technical Committee ISO/TC 213, Dimensional and geometricalspecifications and verification.

ISO 10360 consists of the following parts, under the general title Introductory element Main element:

Part 1: Vocabulary

Part 2: CMMs used for measuring size

Part 3: CMMs with the axis of a rotary table as the fourth axis

Part 4: CMMs used in scanning measuring mode

Part 5: CMMs probing performance with contacting probing system

Part 6: Estimation of errors in computing of Gaussian associated features

Part 7: CMMs equipped with video probing systems

Part 8: CMMs with optical distance sensors

Part 9: CMMs with multiple probing systems

Part 10: Laser Trackers used for measuring point-to-point distances

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Introduction

This part of ISO 10360 is a geometrical product specification (GPS) standard and is to be regarded as ageneral GPS standard (see ISO/TR 14638). It influences link 5 of the chains of standards on size, distance,radius, angle, form, orientation, location, run-out and datums. For more detailed information of the relation ofthis part of ISO 10360 to other standards and the GPS matrix model see annex B.

The tests of this part of ISO 10360 have two technical objectives: (1) to test the error of indication of acalibrated test length using a Laser Tracker and (2) to test the errors in the Laser Tracker. The benefits ofthese tests are that the measured result has a direct traceability to the unit length, the meter, and that it givesinformation on how the Laser Tracker will perform on similar length measurements.

This part of ISO 10360 is distinctfrom that of ISO 10360-2, which is for CMMs equipped with contact probingsystems, in that the orientation of the test lengths reflect the different instrument geometry and error sources

within the instrument.

All the definitions in clause 3 will appear in the next issue of ISO 10360-1.

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ISO 2010 All rights reserved 1

Geometrical Product Specif ications (GPS) Acceptance and

reverification tests for coordinate measuring machines (CMM) Part 10: Laser Trackers

1 Scope

This part of ISO 10360 specifies the acceptance tests for verifying the performance of a Laser Tracker bymeasuring calibrated test lengths as stated by the manufacturer. It also specifies the reverification tests thatenable the user to periodically reverify the performance of the Laser Tracker. The acceptance andreverification tests given in this part of ISO 10360 are applicable only to Laser Trackers utilising a retro-reflector as a probing system. Laser Trackers that use interferometry (IFM), absolute distance meter (ADM)

measurement, or both may be verified using this part of ISO 10360.

This standard does not explicitly apply to measuring systems that do not use a spherical coordinate frame orto systems that use different probing accessories; however, the parties may apply this part of 10360 to suchsystems by mutual agreement.

This International Standard specifies:

performance requirements that can be assigned by the manufacture or the user of the Laser Tracker,

the manner of execution of the acceptance and reverification tests to demonstrate the statedrequirements,

rules for proving conformance, and

applications for which the acceptance and reverification tests can be used.

2 Normative References

The following referenced documents are indispensable for the application of this document. For datedreferences, only the cited editions apply. For undated references, the latest edition of the referenceddocument (including any amendments) applies.

ISO 10360-1:2000, Geometrical Product Specifications (GPS) Acceptance and reverification test forcoordinate measuring machines (CMM) Part 1: Vocabulary

ISO 14253-1:1998, Geometrical Product Specifications (GPS) Inspection by measurement of workpiecesand measuring equipment Part 1: Decision rules for proving conformance or nonconformance withspecifications

ISO 14660-1:1999, Geometrical Product Specifications (GPS) Geometrical features Part 1: Generalterms and definitions

ISO/TS 23165:2006, Geometrical product specifications (GPS) Guidelines for the evaluation of coordinatemeasuring machine (CMM) test uncertainty

ISO/IEC Guide 99:2007,International vocabulary of metrology - Basic and general concepts and associatedterms (VIM).

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3 Terms and Defin itions

3.1interferometric measurement (IFM) modemeasurement method that uses a laser displacement interferometer internal to a laser tracker to determine

distance (range) to a target

NOTE: The target is typically a retroreflector.

3.2absolute distance meter (ADM) measurement modemeasurement method that uses time of flight techniques to determine the distance (range) to a target

NOTE: The target is typically a retroreflector.

3.3retroreflectorpassive device designed to reflect light back parallel to the incident direction over a range of incident angles

NOTE 1: Typical retroreflectors are the cats-eye and the cube corner.

NOTE 2: Retroreflectors are cooperative targets

3.4spherically mounted retroreflector (SMR)retroreflector that is mounted in a spherical housing

NOTE: In the case of an open-air cube corner, the vertex is typically adjusted to be coincident with the sphere center.

3.5length measurement error

EL

error of indication when performing a point-to-point distance measurement using a laser tracker with a probeoffset length ofL

NOTE E0 (used throughout this document) corresponds to the common case of no probe offset length, as the

retroreflector optical center is coincident with the physical center of the probing system.

3.6probing form errorPF

error of indication within which the range of radii can be determined by a least-squares fit of points measured

by a laser tracker on a spherical material standard of size

3.7probing s ize errorPS

error of indication within which the diameter of a spherical material standard of size can be determined by aleast-squares fit of points measured with a laser tracker

3.8probing location errorPL

the apparent Euclidean distance between two measurements taken with the retroreflector placed in a singlelocation, the second measurement being taken with the azimuth axis at approximately 180 degrees from thefirst measurement and the elevation angle reflected about the vertical (e.g. +82 degrees to -82 degrees).

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NOTE: This combination of axis rotation is known as a two face, or plunge and reversetest.

NOTE It is often the case that the Range of two measurements is assumed to be the same, as the range informationmay not be obtainable for the second measurement.

3.9maximum permissible error of length measurementEL, MPE

extreme value of the length measurement error,EL, permitted by specifications

NOTE E0, MPEis used throughout this document.

3.10maximum permissible error of probing formPF, MPE

extreme value of the probing form error, PF, permitted by specifications

3.11maximum permissible error of probing sizePS, MPE

extreme value of the probing size error, PS, permitted by specifications

3.12maximum permissible error of probing location

PL, MPE

extreme value of the probing location error, PL, permitted by specifications

4 Symbols

For the purpose of this part of ISO 10360, the symbols of Table 1 apply.

Table 1 - Symbols

Symbol Meaning

EL Length measurement errorPF Probing form error

PS Probing size error

PL Probing location error (from two face tests)

EL, MPE Maximum permissible error of length measurement

PF, MPE Maximum permissible error of probing form

PS, MPE Maximum permissible error of probing size

PL, MPE Maximum permissible error of probing location (from two face tests)

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5 Environmental and metrological requirements

A manufacturers specification that conforms to this part of ISO 10360 shall include completed Form 1(General Specifications and Rated Conditions Annex A) and the specifications of Form 2 (ManufacturersPerformance Specifications and Test Results Annex A). The manufacturer shall provide a formula for

calculating the maximum permissible error (MPE) for bidirectional length measurements, the MPE for theprobing tests and the two face tests that are applicable over the entire range of rated conditions as describedin Form 1.

5.1 Environmental condit ions

Limits for permissible environmental conditions such as temperature conditions, air pressure, humidity, andvibration at the site of installation that influence the measurements shall be specified by:

the manufacturer, in the case of acceptance tests;

the user, in the case of reverification tests.

In both cases, the user is free to choose the environmental conditions under which the testing will beperformed within the specified limits (as supplied in the data sheet of the manufacturer. See Form 1 Annex A).

5.2 Operating condi tions

The Laser Tracker shall be operated using the procedures given in the manufacturer's operating manual whenconducting the tests given in Clause 6. Specific areas in the manufacturer's manual to be adhered to are, forexample:

a) machine start-up/warm-up cycles,

b) machine self-compensation procedures

c) cleaning procedures for retroreflector,

d) retroreflector qualification,

e) location, type, and number of environmental sensors (i.e. "the weather station"),

f) location, type, number of thermal workpiece sensors.

5.3 Length measurement error ,EL

The length measurement errors, theELvalues, shall not exceed the maximum permissible error,

EL, MPEstated by:

the manufacturer, in the case of acceptance tests,

the user, in the case of reverification tests.

The length measurement errors (the ELvalues) and the maximum permissible error of length measurement,E0L MPE, are expressed in micrometers.

The manufacturer may, at his discretion, specify the maximum permissible error of point-to-point lengthmeasurements when measuring radially (when the reference length is oriented along a radial direction of the

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6.2 Probe errors

6.2.1 Principle

The principle of this test procedure is to measure the size and form of a test sphere using 25 points probed

with the retroreflector and attribute the observed form error to the probing system. A least-squares sphere fit ofthe 25 points is examined for the errors of indication for form and size. This analysis yields the form error, PF,and the size error, PS.

Two types of errors in the SMR may influence the results of this test. If the sphere within which theretroreflector is mounted is out-of-round, this will influence the test result. Also, if the mirrored surfaces whichcomprise the retroreflector are not mutually orthogonal, or if their point of intersection is not coincident with thesphere center, the test result will be affected.

NOTE Most SMRs are of adequate quality such that a properly cared-for SMR will have errors that are smallcompared to the PFresult of the test.

The results of these tests may be highly dependent on the distance of the test sphere from the Laser Tracker.

Therefore, the test shall be performed at two distances from the Laser Tracker, as indicated in Table 2.

Table 2 - Probe testing locations

Distance from Tracker Height relative to Tracker

< 2m ~ same height

~10 m more than 1 m above or below

6.2.2 Measuring equipment

The material standard of size, i.e. the test sphere, shall have a nominal diameter not less than 25 mm and not

greater than 51 mm. The test sphere shall be calibrated for size and form.

6.2.3 Procedure

Mount the test sphere with the support located away from the tracker, so that a full hemisphere may bemeasured.

NOTE The test sphere should be mounted rigidly to minimise errors due to bending.

Measure and record 25 points. The points shall be approximately evenly distributed over at least ahemisphere of the test sphere. Their position shall be at the discretion of the user and, if not specified, thefollowing probing pattern is recommended (see Figure 1):

One point on the pole (defined by the direction of the stylus shaft) of the test sphere:

Four points (equally spaced) 22,5 below the pole;

Eight points (equally spaced) 45 below the pole and rotated 22,5 relative to the previous group;

Four points (equally spaced) 67,5 below the pole and rotated 22,5 relative to the previous group;

Eight points (equally spaced) 90 below the pole (i.e. on the equator) and rotated 22,5 relative to theprevious group.

Note It is suggested that the user follow the manufacturer recommendations for probing locations and SMR

orientation while probing. In the absence of these recommendations, a constant attitude of the SMR throughout the testmay yield smaller PFvalues.

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Key

A Pole point on sphere nominally closest to the Laser Tracker

Figure 1: Location of probing points

NOTE: The result of this test is highly dependent on the skill of the Laser Tracker operator.

6.2.4 Derivation of test results

6.2.4.1

Using all 25 measurements, compute the Gaussian associated sphere. Record the diameter of this sphere.The difference of this diameter from the calibrated diameter of the test sphere, i.e.DMEASDREF, is the probingsize error, PS.

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6.2.4.2

For each of the 25 measurements, calculate the Gaussian radial distance, R.Record the range of radii of the25 points with respect to the least-squares sphere centre, i.e. Rmax Rmin, the apparent sphere form. Theabsolute value of this difference is the probing form error, PF.

6.3 Probing location errors (two-face tests)

6.3.1 Principle

The principle of this test procedure is to measure the location of a single retroreflector twice, whilst rotating theazimuth axis by approximately 180 degrees and reflecting the elevation angle about the vertical between themeasurements. The apparent distance between the two measurements of the retroreflector yields the testresult, PL.

NOTE: As this test is easy to perform, and will immediately reveal problems with the tracker geometry and its

correction, it is recommended that these tests be performed first.

The results of these tests may be highly dependent on the distance of the test sphere from the Laser Tracker,and influenced by the tracker's angular orientation. Therefore, the test shall be performed at two distancesfrom the Laser Tracker and at 3 different orientations, as indicated in Table 3.

Table 3 - Two-face Measurement pos itions

Positionnumber

Distance fromtracker

Description of retroreflector positionAngle(s) withrespect to the

tracker (degrees)

1-3 1 m Two-face test, retroreflector 1 m below tracker height 0, 120, 240

4-6 1 m Two-face test, retroreflector at tracker height 0, 120, 240

7-9 1 m Two-face test, retroreflector 1 m above tracker height 0, 120, 240

10-12 6 m Two-face test, retroreflector 1 m below tracker height 0, 120, 240

13-15 6 m Two-face test, retroreflector at tracker height 0, 120, 240

16-18 6 m Two-face test, retroreflector 1 m above tracker height 0, 120, 240


The equipment for this test is a target nest that may be mounted rigidly at the positions required in Table 3.

6.3.3 Procedure

Mount the target nest so that the nest and its support will not interfere with measurement of the retroreflector.

Place the retroreflector in the nest, and measure the location of the retroreflector in both angles and range.Rotate both angular axes of the tracker by the appropriate angles and reacquire the retroreflector. Measure

this location of the retroreflector in the angles only, using the range value from the first measurement.

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NOTE 1 For Laser Trackers used in IFM mode, it may not be possible to prevent the beam from being broken duringthis test. For this reason, only the first range value is used in the PLcalculations.

NOTE 2 The target nest should be mounted rigidly to minimise uncertainty in the measurements.


Calculate the distance between the two measured locations. This distance between the two locations is theprobe location error, PL.

6.4 Length errors

6.4.1 Principle

The length measurement error describes the three-dimensional deviation behaviour of the Laser Tracker inthe specified measuring volume. This deviation behaviour is caused by the overlapping of different individualdeviations such as uncorrected systematic deviations of the length measuring system and the angle encoders,random measuring deviations, geometric imperfections in the rotation and swivelling axes and/or of the

spherically mounted retroreflector or the probe. As the deviation behaviour depends, among other things, onthe mode of operation, different values of the characteristics may result for different modes of operation(interferometric or absolute distance measurement, vertical or horizontal installation of the Laser Tracker,spherically mounted retroreflector or probe). If the mode of operation is not indicated, the characteristic appliesto all permissible modes of operation of the measuring system.


A traceable reference length may be realized in a number of ways, including scale bars, target nests mountedon walls or freestanding structures, use of a rail-and-carriage system, gauge blocks, ball bars, etc. While anysuch lengths may be used, the measurements of these length tests shall be bidirectional. A bidirectionalmeasurement error can be achieved, for example, using a combination of a unidirectional measurement on areference length and a bidirectional measurement on a short gauge block. See the normative Annex B, which

includes all the details of reference lengths and achieving bidirectional measurements.

A laser tracker uses one linear axis and two rotary axes to determine the location of a retroreflector. Thenormative locations in Table 4 include tests that span at least 66% of each axis. Positions 1 and 2 accomplishthis for each rotary axis separately, while positions 36-40 accomplishes this for the ranging (linear) axis. Theangular range of a measurement is determined by both the length being measured and its distance from theLaser Tracker. It is therefore possible to obtain a variety of angular measurements using a single calibratedreference length. For this reason, the reference lengths in positions 1-29 of Table 4 shall be between 2.25 mand 2.75 m.

The manufacturer shall state the upper, and optionally lower, limits of the CTE of the calibrated test length.The manufacturer may calibrate the CTE of a calibrated test length. The manufacturer shall specify themaximum permitted (k = 2) uncertainty of the CTE of the calibrated test length. In the case where thecalibrated test length is composed of a unidirectional length and other information (see Annex B), the CTEshall be considered to be that of the unidirectional length. The default for a calibrated test length is a normalCTE material unless the manufacturer's specifications explicitly state otherwise. Check that normal CTE isdefined in this part.

A laser interferometer that is corrected for the index of refraction of air has a zero CTE (= 0). Hence, if it isused to produce a calibrated test length it is considered a low CTE material and is subject to 6.3.x.x.Additionally, if the reference laser has a workpiece (material) temperature sensor, then the workpiece CTE inthe lasers software shall be set to 0. If a temperature compensated Laser Tracker is being tested, theworkpiece CTE in the Laser Tracker software shall be set to 0 when measuring these reference lengths.

If the calibrated test length is not a normal CTE material, then the corresponding E0, MPE values aredesignated with an asterisk (*) and an explanatory note shall be provided describing the CTE of the calibratedtest length.

EXAMPLE

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E0, MPE*

* Artefact is super-invar with a CTE no greater than 0,5 106/C and with a CTE expanded uncertainty (k = 2) no greater

than 0,3 106/C.

For the case where the manufacturer's specification for E0, MPErequires a CTE less than 2 x 106

/C (thus being a non-normal CTE), an additional measurement shall be performed on a normal CTE material reference length. See normativeAnnex C.

NOTE: Due to the large size of reference lengths required for testing Laser Trackers, it is common for this low-CTEoption to be exercised.

6.4.3 Procedure

Place the reference length(s) at each location and orientation relative to the Laser Tracker described in Table4. If in the case of IFM measurements the beam is broken during a length measurement, themeasurement during which the beam was broken must be restarted, but the series of three measurementsneed not be restarted (unless, of course, the beam was broken during the first length measurement). In thecase of ADM measurements, it is suggested that the beam be broken during each length measurement,

forcing the Laser Tracker to re-establish the distance to the reflector as part of the measurement process.

NOTE: In many instances, it may be easier to move or reorient the Laser Tracker than to move the reference length.

Table 4 - Measurement positions

Position numberDistance from

trackerDescription of reference length position

Horizontalangle(s) withrespect to the

tracker(degrees)

1As close as

practical

Horizontal, centered (i.e., the ends of the reference

length are equidistant from the tracker), and attracker height.

This tests 66% of the horizontal angle measurementaxis of the tracker.

at any azimuth

2As close as

practical

Vertical, center of the length at tracker height (endsof the reference length equidistant from the tracker).

This tests 66% of the vertical angle measurementaxis of the tracker.

at any azimuth

3-6 3 mHorizontal, centered (i.e., the ends of the reference


0, 90, 180, 270

7 3 mVertical, center of the length at tracker height (endsof the reference length equidistant from the tracker).

at any azimuth

8-11 3 mRight diagonal, centered (i.e., the ends of the

reference length are equidistant from the tracker),

and the center of the length is at tracker height.

0, 90, 180, 270

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12-15 3 mLeft diagonal, centered (i.e., the ends of the

reference length are equidistant from the tracker),and the center of the length is at tracker height.

0, 90, 180, 270

16-19 6 m

Horizontal, centered (i.e., the ends of the reference


0, 90, 180, 270

20-23As close as

practicalHorizontal, not-centered (i.e, the tracker is directly infront of one end of the length), and at tracker height

0, 90, 180, 270

24As close as

practicalVertical, not-centered (i.e, the tracker is directly in

front of one end of the length)at any azimuth

25-28As close as

practical

Diagonal, one end below or above the point directlyin front of the tracker, the other end to the right orleft of the point directly in front of the tracker. The

range to the two ends of the length are equal.

0, 90, 180, 270

29Horizontal, centered directly above (as much as that

ispossible) the laser tracker itselfat any azimuth

30-35 Long1

Horizontal, centered (i.e., the ends of the referencelengthare equidistant from the tracker), at tracker

height

0, 30, 60, 90,120,150

36-405 Ranging test

distancesThis tests 66% of the ranging axis of the tracker. at any azimuth

41

Synthetic

length

test

See Annex C

1In the special long case, a longer reference length (e.g., 8 m) is measured at a longer distance (e.g., 8 m)

from the tracker.

In the Ranging tests (lengths 36-40), it is not required that each of the 5 lengths be measured as a two pointdistance. It is permitted to measure a reference point close to the tracker (e.g. less than 1 m from the tracker)and then 5 points at increasing distances, where the 5 reference lengths are all calculated from the commonfirst point. The user may, at his discretion, require that the first point be measured more than once (up to a

maximum of 5 times, once for each length).

In explanation, if the points are labeled A (closest) to F (farthest), a sequence of measurements ABCDEF ispermitted to evaluate the ranging capability of the laser tracker. The user may, however, require that eachlength remeasures the A location as in (AB, AC, AD, AE, AF) or (AB, CA, AD, EA, AF).

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a) 1, 3-6, 16-19, 30-35 b) 2, 7 c) 8-11 d) 12-15

e) 20-23 f) 24 g) 25-28 h) 29

Key: A and B are the ends of the artifact, d is perpendicular to the vertical plane containing the artifact

Figure 2: Positions for reference artifact

For

6.4.3.1 User defined posi tions: alternative 1

The user is free to choose the remaining 64 measurement positions (for a total of 105 measurements). Toassist the user in choosing these measurement positions, two alternative default positions are given.Alternative 1 is described in Table 5 below.

Table 5 Supplemental default measurement positions Alternative 1

position numberDistance from


Angle(s) withrespect to the

tracker (clockedabout vertical

axis)

1-3 3 m Vertical, centered (i.e., the ends of the referencelength are equidistant from the tracker), and thecenter of the length is at tracker height.

90, 180, 270

4-7 6 m Vertical, center of the length at tracker height (endsof the reference length equidistant from the tracker).

0, 90, 180, 270

8-11 6 m Right diagonal, centered (i.e., the ends of thereference length are equidistant from the tracker),and the center of the length is at tracker height.

0, 90, 180, 270

A

dd

B

A

d

B

A

d

A

d

B

A

d

B

A

dB

A

dB

A

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axis)

12-15 6 m Left diagonal, centered (i.e., the ends of thereference length are equidistant from the tracker),and the center of the length is at tracker height.

0, 90, 180, 270

16-18 As close aspractical

Vertical, not-centered (i.e, the tracker is directly infront of one end of the length)

90, 180, 270


Horizontal, not-centered (i.e, the tracker is directly infront of one end of the length), and at tracker height.This is the mirror position corresponding to positions20-23 in Table 4 (If the tracker were previouslydirectly in front of Target B as in Fig. ?, then, thetracker must now be positioned directly in front of

target A)

0, 90, 180, 270


Vertical, not-centered (i.e, the tracker is directly infront of one end of the length). This is the mirrorposition corresponding to positions 24 in Table 4 andpositions 16-18 in this Table (If the tracker werepreviously directly in front of Target B as in Fig. ?,then, the tracker must now be positioned directly infront of target A)

0, 90, 180, 270


Diagonal, one end below or above the point directlyin front of the

tracker, the other end to the right or left of the pointdirectly

in front of the tracker. The range to the two ends ofthe length are equal. This is the mirror positioncorresponding to positions 25-28 in Table 4 (If thetracker were previously directly in front of Target Bas in Fig. ?, then, the tracker must now be positioneddirectly in front of target A)

0, 90, 180, 270

31-33 Horizontal, centered directly above (as much as thatis

possible) the laser tracker itself

90, 180, 270

34-37 6 m Body diagonal of a cube 0, 90, 180, 270


Diagonal, centered (i.e., the ends of the referencelength are equidistant from the tracker), and thecenter of the length is at tracker height.

0, 90, 180, 270

Repeatabilitymeasurements:

42-45 Distanceapproximatelyequal to halfthe referencelength

Horizontal, centered (i.e., the ends of the referencelength are equidistant from the tracker), and attracker height.

Repeat the measurement 4 times.

This tests the repeatability of the horizontal anglemeasurement capability.

at any azimuth

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axis)

46-49 Distanceapproximatelyequal to twicethe referencelength

Horizontal, centered (i.e., the ends of the referencelength are equidistant from the tracker), and attracker height.


This tests the repeatability of the horizontal anglemeasurement capability.

at any azimuth

50-53 Distanceapproximatelyequal to halfthe referencelength



This tests the repeatability of the vertical angle

measurement capability.

at any azimuth

54-57 Distanceapproximatelyequal to twicethe referencelength



This tests the repeatability of the vertical anglemeasurement capability.

at any azimuth

58-61 3 m Along the radial direction so that the near end of thelength is 3 m away from the tracker.


This tests the repeatability of the rangemeasurement capability.

at any azimuth

62-64 6 m Along the radial direction so that the near end of thelength is 6 m away from the tracker.


This tests the repeatability of the rangemeasurement capability.

at any azimuth

6.4.3.2 User defined posi tions: alternative 2

In this alternative, the laser tracker is positioned centrically in front of the longest side of the measuring volumeat a distance of 1.5 m in such a way that the measuring head is approximately equidistant from the upper andlower edge of the measuring volume. The positions are determined by eight different measurement lines.Figure 3 shows a possible arrangement of these eight measurement lines. Other arrangements are alsopermitted.

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Figure 3: Example showing the arrangement of the measurement lines for the test of the

length measurement error

For the remaining 64 positions in this alternative of the acceptance test, a measuring volume of 10 m x 6 m x 3

m (length x breadth x height) is recommended. If the laser tracker is preferably used to measure small parts, ameasuring volume of 5 m x 3 m x 2 m is then recommended. Other measuring volumes are, however,permitted. In every measurement line, at least three different test lengths must be measured. All in all, 64reference lengths should be measured along the eight measurement lines, i.e. in individual measurementlines, 3 or 4 separate lengths could be measured, rotating the tracker between measurements. Before eachmeasurement, the laser tracker shall be rotated by approximately 120 about its vertical axis. The shortest testlength should amount to at least 1/10 of the shortest side of the specified measuring volume. In eachmeasurement line, the largest reference length has to be chosen in such a way that it is not shorter than 2/3 ofthe length which is maximally possible in the measurement line within the measuring volume.

Annex D indicates how targets on a wall can be used, along with carefully adjusting the laser tracker position,to achieve the effect of the measuring volume above in figure 2.


For all 105 measurements, calculate each length measurement error, EL, by calculating the differencebetween the indicated value and the calibrated value of each reference length (where the calibrated value istaken as the conventional true value of the length). The indicated value of a particular measurement of acalibrated test length may be corrected by the laser tracker to account for systematic errors, or thermallyinduced errors (including thermal expansion) if the laser tracker has accessory devices for this purpose.Manual correction of the results obtained from the computer output to account for temperature or othercorrections shall not be allowed when the environmental conditions satisfy the conditions of 5.1.

For each of the 105 length measurement errors (E0values), calculate a corresponding MPE value (E0, MPEvalue) based on the manufacturers MPE specification.

NOTE: The manufacturers MPE specification will, in general, be a formula.

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renovation contract, or

upgrading contract etc.,

the acceptance test specified in this part of ISO 10360 may be used as a test for verifying the performance of

the Laser Tracker used for measuring linear dimensions in accordance with the specification for the statedmaximum permissible errors,E0, MPE, PF, MPE, PS, MPE, and PL, MPE, as agreed upon by the manufacturer and theuser.

The manufacturer is permitted to specify detailed limitations applicable for E0, MPE, PF, MPE, and PS, MPEand PL,MPE. If no such specification is given,E0, MPE, PF, MPE, PS, MPEand PL, MPEapply for any location and orientation inthe measuring volume of the Laser Tracker.

8.2 Reverification test

In an organization's internal quality assurance system, the performance verification described in this part ofISO 10360 can be used as a reverification test to verify the performance of the Laser Tracker used formeasuring linear dimensions in accordance with the specification for the maximum permissible errors, E0, MPE,PF, MPE, PS, MPE, and PL, MPE, as stated by the user. The user is permitted to state the values of, and to specifydetailed limitation applicable to,E0, MPE, PF, MPE, and PS, MPE.

NOTE 1 The tester accounts for the test uncertainty according to ISO 14253-1; accordingly a reverification test (wheretypically the tester is the user) may have a different conformance zone than in an acceptance test.

NOTE 2 In acceptance testing, the conformance zone is derived from the manufacturers specifications. Inreverification testing, the reverification limits may be derived from the users metrological needs.

8.3 Interim check

In an organization's internal quality assurance system, a reduced performance verification may be usedperiodically to demonstrate the probability that the Laser Tracker conforms with specified requirementsregarding the maximum permissible errors, E0, MPE, PF, MPE, PS, MPEand PL, MPE. The extent of the performanceverification as described in this part of ISO 10360 may be reduced by using fewer measurements andpositions (see Annex E).

NOTE This International Standard is primarily concerned with acceptance and reverification testing. Interim testing isoften associated with quality assurance.

9 Indication in product documentation and data sheets

The symbols of Clause 0 are not well suited for use in product documentation, drawings, data sheets, etc.

Table 5 gives the corresponding indications which are also allowed.Table 5 Symbols and corresponding indications in product documentation, drawings, data sheets,

etc.

Symbol used in this document Corresponding indication

E0 E0

PF PF

PS PS

PL PL

E0, MPE MPE(E0)

PF, MPE MPE(PF)

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Symbol used in this document Corresponding indication

PS, MPE MPE(PS)

PL, MPE MPE(PL)

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Annex A(normative)

FORMS

Form 1 General Specifications and Rated Conditions

RATED CONDITIONS

Measurement Envelope

Distance (Range) Min. ______ m Max. ______ m

Horizontal Angle (Azimuth) Min. ______ deg Max. ______ deg

Vertical Angle (Elevation / Zenith) Min. ______ deg Max. ______ deg

or

Length x width x height (Prismatic Volume) ______ m by ______ m by ______ m

a. Temperature Range

Operating Min. ______oC Max. ______

oC

Thermal gradient limits Max. ______oC/m Max. ______

oC/hr

b. Humidity Range

Operating Min. ______ %RH Max. ______%RH

c. Barometric Pressure Range

Operating Min. ______ mm Hg Max. ______ mm Hg

d. Ambient Light: The manufacturer shall identify conditions, if any, under which ambient light degrades specifications.

e. Electrical Voltage ______ V Current ______ AFrequency ______ Hz Surge/sag ______ V

Transient max. ______ V Transient duration ______ s

f. Allowable orientations (vertical, horizontal, etc.) ________________________

g. Probe type: The probe diameter and reflector type (e.g., cube corner, glass prism) used during performance testing shall be

specified.

Diameter ______ mm Reflector type ____________

h. Reference artefact

CTE Min. ______ 10-6

/oC Max. ______ 10

-6/oC

CTE uncertainty Max. ______ 10-6

/oC

i. Sampling Strategy: The manufacturer shall state the measurement acquisition time (averaging time) and sampling frequency (points

per second) to meet specification.

Acq. time ______ s Frequency ________ points/s

j. Warm up time

Warm up time ______ minutes

LIMITING CONDITIONS

k. Temperature Range Min. ______oC Max. ______

oC

l. Humidity Range Min. ______ % RH Max. ______% RH

m. Barometric Pressure Range Min. ______ mm Hg Max. ______mm Hg

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Form 2 Manufacturers Performance Specifications and Test Results (All Units m)

E0, MPE

Length Errors E0

Pass/Fail

PS, MPE

PS

Probing size and formerrors

Pass/Fail

PF, MPE

PF

Pass/Fail

PL, MPE

Probing location errors PL

Pass/Fail

Test Performed by

Date

Serial number

Final test results (Pass/Fail)

As different MPE's are

permitted for different

tests, this table may be

extended to accommodate

the complete specification.

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Annex B(normative)

CALIBRATED TEST LENGTHS

Calibrated Artifacts: Gage Blocks, Ball Bars

Scale bars: End-to-end distance of spheres in the nests is calibrated

Rigid nests: Center-center distance determined from traceable measurement + short bi-directional length.

Rail or carriage system: Location of different instances of a sphere or nest + short bi-directional length.

[A paragraph discussing the addition of a short bi-directional measurement to a uni-directional measurementwill be added here].

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Annex C(normative)

THERMAL COMPENSATION OF WORKPIECES

Measurement of a synthetic test length for proport ional consideration of the thermal specimenexpansionThe acceptance and reverification of laser trackers close to the practice requires the measurement of largetest lengths which can easily be established in situ with the aid of a calibrated laser interferometer (seeAnnex A). Test lengths "in air with a thermal expansion coefficient of approx. 110

6/K place, however, lower

demands on the accuracy of the temperature determination compared to test lengths on gauge blocks of steelwith a thermal expansion coefficient of 11,510

6/K. In the first case, an error of 1 K causes a change in length

of approx. 1 m per meter. When a steel gauge block is measured, the same temperature deviation of 1 Kwould, however, cause a change in length of 11,5 m per meter. In addition it can, in some situations, beadvantageous to use, for the realization of large lengths, artefacts with a small thermal expansion coefficientto reduce influences resulting from the fact that the artefact is not in thermal equilibrium.

This means that in cases in which the test length is not made of a material with a thermal expansioncoefficient between 810

6/K and 1310

6/K and in which the influence of the temperature on the length is

smaller than 2106

/K, a mathematical correction of the length measurement errors is required which allows forthe thermal expansion of an artefact with a normal thermal linear expansion coefficient when the lengthmeasurement error of an artefact is determined. For this purpose, a "synthetic test length is measured whichis at least half as long as the longest side of the measuring volume. With a calibrated reference interferometer,which has been traced back and which may also be the calibrated interferometer of a second laser tracker, atest length between two ball nests is established. Air temperature, air pressure and air humidity are measuredby the weather station of the reference interferometer and, thus, the refractive index of the air is determinedand the refractive index of the test length compensated. The measurement result is the calibrated length L ofthe test length. The length L is now used to calculate a "synthetic test length L S, equivalent to the length of a

gauge block with the thermal expansion coefficient of exactly S= 11.5 m/m/K. The effect of this calculationis that the test length is being changed in such a way that it corresponds to a length with a thermal expansioncoefficient of 11,5 10

-6/K.

LS= L x [1 - Sx (T-20C) ] = L x [1 (11,5 x 10-6

) x (T-20C) ]

The specimen temperature T required for the calculation is measured with a calibrated thermometer on apiece of steel and not with the aid of any temperature measuring system delivered with the laser tracker. Thepiece of steel is in thermal equilibrium with its environment. After that, the "synthetic test length between thetwo ball nests is measured with the laser tracker to be tested. For this purpose, it is recommended to installthe laser tracker at a short distance and in direct extension to the test length. As thermal expansion coefficient,

S = 11.510-6/K must be entered for the specimen. For the laser tracker, the test length thus seems to bemade of steel. To compensate the thermal expansion of the specimen, the temperature of a piece of steel

which has reached thermal equilibrium with its environment, is measured as above - with the sensor for thespecimen temperature. If the laser tracker is not equipped with a sensor of its own for the specimentemperature, it must be proceeded as in usual operation. The measurement of the "synthetic test length withthe laser tracker is repeated three times.

The "synthetic length measurement error ES results from the difference between the test length La, measuredwith the laser tracker, and the "synthetic test length LS.

ES= La LS

For proportional consideration of the thermal expansion of the specimen during testing of the lengthmeasurement error, the mean synthetic length measurement error ESM = (ES1+ES2+ES3)/3 is required andadded in proportion to the length to all other length measurement errors. For this purpose, an individual

correction value Eki is calculated for each test length L r. EKi= Lrx ESM/LS

This section has been taken from the VDI/VDE document needs further discussion

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Annex D(informative)

ACHIEVING THE ALTERNATIVE MEASURING VOLUME

For testing of the length measurement error it is permitted to arrange all measuring lines e.g. in one plane. Inthat case, before test lengths along a measuring line are measured, the laser tracker must each time be newlypositioned so that the relative relation between laser tracker and measuring line with respect to position andorientation is preserved. Figure D1 shows for the recommended measuring volume of 10 m x 6 m x 3 m apossible plane arrangement of the measuring lines with changing positions for the laser tracker, equivalent tothe measurement of test lengths from a permanent position as shown in Figure 3 (see clause Fejl!Henvisningskilde ikke fundet.).

Figure D1: Example of a plane arrangement of the measuring lines for testing of the length

measurement error. The laser tracker is standing on changing positions.

A measuring and test arrangement as shown in Figure D1 can be realized with the aid of stable tripods or bymeans of a stable wall. It is, for example, possible to mount magnetic nests for spherically mountedretroreflectors on one wall. The distances between the nests then represent the test lengths. If the distanceshave been calibrated before the laser tracker is tested, the distances have to be stable only for the duration ofthe test. It is recommended to calibrate the respective test lengths only immediately before a measuring line ismeasured and to determine them again for control immediately after the lengths have been measured with thelaser tracker to be tested. For the acceptance test, a measuring volume of 10.000 mm x 6.000 mm x 3.000mm (length x width x height) is recommended (see 4.2.3) in which 32 test lengths must be measured alongeight measuring lines from a position outside the measuring volume, supplemented by three additional testlengths which must be measured "from the centre". For the recommended arrangement of the measuring line(see Figure D1) the following measures are obtained for the shortest and the longest length to be tested (seeTable D1).

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Table D1: Shortest and longest test length along the measuring lines in figure.

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Annex E(informative)

INTERIM TESTING

ISO/WD 10360-10

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