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2015 Celebrating the Year of Light - Design 14
Type C Goniometer
Fig 1: This goniometer delivers a simple to use platform for in-house testing of a wide range of luminiaire configurations. The meter can be located anywhere from 24" to 96" from the optical center of the luminaire.
Goniometer - table
Fig 2: Rotation of the vertical axis is accommodated using a CNC rotary table and ring bearing base.

Goniometer - Head
Fig 3: Fixture mounting is a second rotary table with T-slots to attach adapter plates to.


Goniometer - The Meter
Fig 4: The meter attachment post can accommodate any instrument the customer might want to use, from simple light meters for quick tests, to more involved spectroradiometric testing

Goniometer - Alignment
Fig 5: a laser line tool attachment aligns the fixture rail with the meter rail to assure squareness of the setup.
Goniometer - Table-Top Version
Fig 6: An earlier example of a bench-top system was designed for testing of small light engines and LED optics, shows the same basic configuration in a smaller scale.

D14: Test Lab Type C Goniometer
This week's design is about light measurement, particularly in an easy to use, and simple to setup platform.

This is a horizontal Type C configuration, which rotates the fixture around a fixed vertical axis, as well as the horizontal axis.  This is a common approach to general lighting products.  The design includes a rail based meter mount, as well a rail for the vertical fixture platform.  This makes setup much easier, in that moving the meter and luminaire mount along the rails maintains alignment of the two to one another.  Rotation of the luminaire in the vertical and horizontal axis is accomplished using CNC mini-mill rotary tables, actuated by remote control.  These can be rotated in increments as small as .006 degrees, with 2.5, 5, and 10 being the most commonly used.  The vertical axis rotation table is mounted to a large diameter rotary bearing, which can support 600 pounds.

Included in the setup are alignment tools. One is mounted to the center of the fixture horizontal axis (a modified rifle bore sight) aimed at the center of the meter's receptor window. The other (contractors laser line tool) is located on the rail below - emitting a vertical line for checking the zero position of the vertical axis rotating table.  With theses two in alignment the rig is set to go.  Mount the fixture using adapter plates to the horizontal axis, set the optical source to the center of the of the vertical axis, light it up,  the let the temperature stabilize, and start testing.

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