Traditional lux meters are increasingly being replaced by spectral light meters such as the MSC15. However, the lighting industry also needs high accuracy spectral light meters that can handle more complex measurements. These include measurement of pulse width modulated light and the ability to measure both internal and external illumination, determination of thermal transient behavior of lamps, and so on. The primary criterion that such meters must always meet is the quality of their photometric features. Additional electronic features may improve usability and display quality, but they cannot compensate for substandard measurement results.
Manufacturers of lamps and luminaires for general lighting purposes must consider light flicker when qualifying product safety in terms of EMC immunity requirements. In addition to the influence of mains voltage fluctuations, flicker effects caused by the lamp and the luminaire itself must be taken into account.
With the BTS256-EF, Gigahertz-Optik GmbH, a renowned measuring device manufacturer, offers a universal measuring device for the determination of all relevant light parameters in general lighting. Combined with a programmable AC source, the BTS256-EF becomes a comprehensive flicker test system for lamps and luminaires including voltage fluctuation immunity tests IEC TR 61547-1:2017.
BTS256-EF – Highquality, spectral light and color measurement meter
The BTS256-EF is a high-quality measuring device for photometric and colorimetric measurement of general lighting products and conditions. A special feature of the meter is a Bi-Tec sensor. This consists of a fast photodiode and a CMOS array detector. Thus, the meter supports all the requirements of a modern light meter:
- Cosine field of view illuminance measurement for accurate evaluation of extended illumination (class B DIN 5032 part 7 or AA according to JIS C 1609-1:2006)
- Flicker measurement
- Spectral measurement technology, required for LED light, color, color rendering, color effects
- Photodiode for synchronization to pulse width modulated light and flicker measurement
- alpha-opic illuminance and irradiance measurement (CIE S 026:2018)
- Compact and robust design for mobile use
BTS256-EF – Flicker meter
In its function as a light-flicker meter, the BTS256-EF supports all current flicker measurements:
- Percent Flicker (IEEE Std 1789-2015, IES: RP-16-10, CIE: TN-006)
- Flicker Index (IEEE Std 1789-2015, IES: RP-16-10, CIE: TN-006)
- FFT Frequency component analysis
- Pst Short term flicker severity (CIE: TN-006, IEC TR 61547)
- Stroboscopic Visibility Measure, SVM (CIE: TN-006, IEC TR 63158)
- Mp ASSIST Flicker perception metric
- Joint Appendix JA10
In addition, the BTS256-EF allows flicker tests according to IEC TR 61547 when operated in combination with power supply LPS-CH-500. These tests aim to probe flicker stability when light sources are operated in an AC circuit under the influence of disturbance signals.
BTS256-EF – Meter for photosynthetically active radiation (PAR) in plant growth
LED grow lights need to be measured in terms of the Photosynthetically Active Radiation (PAR) they produce. This function is supported by the BTS256-EF. The Photosynthetic Photon Flux Density (PPFD) in µmol/(m²*s) can be measured which is a measure of the total number of photons within the PAR wavelength range that reach a surface each second per square meter area. Furthermore, the daylight integral (DLI) can be displayed which represents the total amount of photosynthetically active radiation received by a plant in the course of a day.
Calibration of the BTS256-EF
One essential quality feature of photometric devices is their precise and traceable calibration. The BTS256-EF is calibrated by Gigahertz-Optik’s calibration laboratory that was accredited by DAkkS (D-K-15047-01-00) for the spectral responsivity and spectral irradiance according to ISO/IEC 17025. The calibration also included the corresponding accessory components. Every device is delivered with its respective calibration certificate.
Options for the BTS256-EF light meter
- Software development kit for integration of the device in the user’s own software
- In combination with software tool S-T-Flicker and the programmable AC Source LPS-CH-500 Gigahertz-Optik GmbH offers a functional extension of the BTS256-EF for an test system according to the IEC TR 61547-1:2017 Equipment for general lighting purposes - EMC immunity requirements - Part 1: An objective light flicker and fluctuation immunity test method.
2) Precision cosine diffuser
3) BiTec sensor with Si photodiode, CMOS diode array spectrometer and shutter
4) Photometric Si-photodiode with fast amplifier
7) Control Buttons
8) USB 2.0 interface
9) Light incident
BTS256-EF Flicker Measurement
BTS256-EF Flicker Measurement
BTS256-EF Flicker Measurement
Spectroradiometer for the illuminance (photopic, scotopic, melanopic), PAR, spectrum, light color, color rendering index, and flicker
Mobile measurement device, BiTec sensor with a V-lambda photodiode and low stray light CMOS spectroradiometer with a 10 nm optical bandwidth and additional optical bandwidth correction (CIE214), remote-controlled offset shutter, precise cosine-corrected field of view, data logger, automatic PWM synchronization, flicker measurement of Pst, SVM, Flicker Index, etc.
1 lx to 199,000 lx, 360 nm to 830 nm, flicker frequency between 0.25 Hz and 40 kHz
Precise spectral light meter for the lighting industry
Factory calibration, traceable to international standards
class B DIN 5032 part 7 or AA according to JIS C 1609-1:2006
Bi-Technology sensor with a photometric broadband detector and a array spectrometer. Integrated aperture for automatic dark signal adjustment.
Diffuser window with 20mm diameter, cosine corrected field of view, f2 Error ≤ 3%
Spectral responsivity with fine CIE photometric matching. Online correction of the photometric matching through spectral measurement data (spectral missmatch factor correction)
Measurands: Percent flicker (IES:RP-16-10, CIE:TN-006), flicker index (IES:RP-16-10, CIE:TN-006), flicker frequency, fast fourier transformation (FFT), Pst short-term flicker severity Pst (CIE:TN-006, IEC TR 61547), stroboscopic effect visibility measure SVM (CIE:TN-006, IEC TR 63158), Mp ASSIST, joint appendix JA10.
The BTS256-EF has a limited internal memory and can thus only access the following frequency range when used as a handheld meter (without a PC):
The measurement range extends to the following range when the BTS256-EF is used in combination with a PC and the S-BTS256 or S-SDK-BTS256 software:
(360 - 830) nm
10 nm, mathematical optical bandwidth correction according to CIE 214 can be automatically applied
(5.2 - 30000) ms
Automatic aperture for dark signal measurements with the same integration time as that of light measurements. Aperture delay = 100ms.
|typical measurement time||
199,999 lx ≤ 5ms (white light)
100 lx ≤ 1s (white light)
|Color measurement range spectral||
(1 - 199,999) lx
Scotopic measurement range spectral (1 - 199,999) lx
|Repeatability Δx and Δy||
+/- 0.0001 (Standard illuminant type A)
+/- 0.0002 (LED)
|Δy Δx uncertainty||
+/- 0.002 (Standard illuminant type A)
+/- 0.005 (typ. LED)
|CCT Measurement range||
(1700 - 17000) K
+/- 50K (standard illuminant type A)
+/- 4% (depending on the LED spectrum)
|CRI (color rendering index)||
Ra and R1 to R15
6E-4 (Blue LED)
6E-4 (Green LED)
6E-4 (Red LED)
1E-3 (White LED)
(typical value, measured 100 nm to the left of the peak of the LEDs)
Spectral irradiance responsivity (360 - 830) nm
Illuminance ± 2.2%
|f1' (spectral mismatch)||
≤3% (f1' a*(sz(λ)) respectively F*(sz(λ)) corrected by spectral data, done automatically by BTS technology)
|Noise equivalent illuminance||
(0.1 - 6000) ms
The measured values of the diode are corrected by means of an internal temperature sensor.
|f2 (directional response/cosine error)|
16Bit, 25ns instruction cycle time
5VDC, 450mA per USB
USB 2.0 (Type B USB)
Option WiFi: WiFi 2,4 GHz (external antenna, range > 100m)
Operation: +10°C bis +30°C
Storage: -10°C bis +50°C
333mm x 280mm x 70mm, 650g
159mm x 85mm x 45mm (Length x Width x Height)
|BTS256-EF Technical data sheet||BTS256-EF brochure|
|Brochure||Light measurement solutions for general and specialized lighting|
|Produktname||Product Image||Description||Show product|
|S-SDK-BTS256||Software Development Kit for BTS256 variants.|
|S-BTS256||Application software for BTS256 variants.|