LED calibration standards in the ACS series

As market leader for LED metrology, Instrument Systems also offers calibration standards on an LED basis. The ACS-570 series has been configured for the photometric quantities of luminous intensity or rather averaged LED intensity and luminous flux. The ACS-585 is suitable for the calibration of luminance. With both LED calibration standards, color coordinates x and y can additionally be verified.

The LED calibration standards enable simple and reliable check of the calibration of Instrument Systems measuring instruments. If necessary, the photometric absolute value can be recalibrated according to the substitution method recommended by the CIE.

ACS_LED calibration standards

General features

  • Temperature stabilized, cooled high-power LED in housing with very low thermal conductivity guarantees extremely high photometric stability
  • Calibration is traceable to national standards
  • Advantageous recalibration of measuring systems at customer’s location
  • 0.5 % photometric stability over min. 100 operating hours
  • Highest degree of operational reliability due to the elimination of manual settings when used with the PSU 10 control unit
  • Comprehensive solution with power source, temperature stabilization and software

Features of the ACS-570

  • Reference values for luminous flux and medium luminous intensity, traceable to PTB standards (conforming to DIN ISO 17025)
  • Specification of color coordinates, dominant wavelength and color temperature
  • Available in the primary colors red, green, blue and white
  • Calibration standard for radiant flux in UV available from Fall 2019

Features of the ACS-570-15/17

  • Reference value for radiant flux in infrared (IR) region
  • Available for typical peak wavelengths 860 nm and 950 nm
  • Maximum operational reliability when used with PSU 10 unit

Features of the ACS-585

  • Reference values for luminance
  • Specification of color coordinates and color temperature
  • Supports the testing of all luminance meters on both filter and spectroradiometric basis

Technical Specifications

ACS GeneralACS-570             ACS-585
LEDDominant wavelength [nm] or color
temperature Tn [K]
Averaged LED Intensity   Luminous fluxluminance
White  5000 - 6000 K15 - 20 cd15 - 20 lm400 - 600 cd/m²
Blue480 nm5 - 10 cd 5 - 10 lm-/-
Green530 nm15 - 20 cd15 - 20 lm-/-
Red622 nm8 - 12 cd 8 - 12 lm-/-
Temperature at the control point35 °C +/-0.05 °C
Temporal stability0.1 % / 12 h and 0.5 % / 100 h
Temporal stability of the color coordinates0.0002 / 12 h and 0.0005 / 100 h in x and y
Electrical connectionsSub-D, 25-pole (ACS to PSU 10); USB (PSU 10 to PC)

Note: All values are typical data

Substitution method

Substitution method means that a reference standard is used to calibrate an instrument whose characteristics match those of the actual measurement object as closely as possible. This is the rigorous way of referencing the calibration directly on national standards.
The fact that LEDs are not point light sources under standard measurement conditions and their spectral power distribution as well as spatial radiation pattern differs significantly from that of a halogen lamp means that only an LED can be used as a reference for photometric and radiometric absolute calibration.