LGS 650 Goniophotometer for medium and large light sources

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Angle-dependent determination of photometric quantities

The LGS 650 was specially developed for the determination of angle-dependent spatial radiation properties of medium-sized to large SSL sources and LED modules, and is a space-saving and attractively priced alternative to the larger LGS 1000.

The sample is measured in a horizontal burning position and moved over an angle range of ± 160° in the direction of radiation of the sample around the gamma axis. The high angle resolution of 0.01° guarantees highly accurate and reproducible readings. The LGS 650 permits the mounting of samples with a diameter of 1300 mm and a maximum weight of 10 kg. It complies with all relevant CIE, DIN and IES standards.

Combined with an Instrument Systems spectroradiometer, e.g. the CAS 140D, radiometric, colorimetric and photometric quantities can be determined with the greatest precision as a function of angle. For particularly time-critical measurements, Instrument Systems offers the appropriate photometers such as the new DSP 200. These can be used for “on the fly” measurements, i.e. while the goniophotometer is in motion. The measurements are analyzed by our extensive SpecWin Pro spectral software.

LGS 650 – Highlights:

  • Type C goniophotometer for samples with a diameter up to a  1300 mm and a weight of 10 kg
  • Precise determination of luminous intensity distribution and luminous flux
  • Angle-dependent analysis of spectral and colorimetric quantities
  • Data export in IES and EULUMDAT format
  • Easy and intuitive control of the measurement process, as well as power supply and electric measurement of the sample
  • Configurable switch-on and stabilization routines for the sample in repetitive measurement tasks
  • Extensive and adaptable measurement logs and reporting functions

From colorimetric spatial radiation properties to luminous flux integration

Depending on the specific measurement task, the relevant guidelines recommend use of a goniometer with a photometer or spectroradiometer. For both variants Instrument Systems offers instruments with the highest degree of measurement accuracy.

Like the LGS 350, the LGS 650 has a universal sample holder for a wide range of measurement tasks on medium-sized LED modules and luminaires. The many possible applications range from checking compliance with standards to energy efficiency classification.

Examples of applications

LGS 650 – Technical data



Travel range C-axis -70° to +250°, safeguarded by limit switches
Travel range γ-axis ±160°, safeguarded by limit switches
Resolution of angle encoder 0.01°
Reproducibility C-axis ≤ 0.1° (under max. sample load)
Reproducibility γ-axis     ≤ 0.05° (under max. sample load)
Dimensions (H x W x D); weight    1732 x 502 x 727 mm3; 101 kg
Max. sample size/weight   1340 mm / 10 kg
The detailed measurement conditions under which the specified values have been determined can be looked up in the data sheets and brochures or requested from Instrument Systems.