The Gigahertz-Optik BTS256-E is a high-quality portable light meter that is well suited for illuminance and luminous colour measurements in many application areas due to its compact design, high-quality light sensor and precise cosine field of view function. The instrument is suitable for tripod mounting if required, and is easy to operate via 3 function keys.
Instrument Hire models are supplied with the S-BTS256-E software that allows all the functions necessary for data transfer. All units are as standard supplied with a rechargeable battery pack via the USB style charger. The unit can be used for logging purposes.
Features
The BTS256-E offers the user fourteen different measurement parameters :-
- Ep Photopic illuminance
- Es Scotopic illuminance
- Es/Ep Ratio of night and daylight vision
- EVE “Equivalent Visual Efficiency” factor
- Ee Irradiance
- Eλ Spectral irradiance
- x, y CIE 1931 color coordinates
- u‘, v‘ CIE 1976 color coordinates
- CT Color temperature
- Δuv Deviation from the blackbody locus
- λdom Dominant wavelength
- λp Peak intensity wavelength
- λ0,5 Spectral half-width
- Purity Color purity
- CRI Ra and R1 to R15 Color Rendering Index
Technical
One of the outstanding properties of this mobile light meter is its BiTec light sensor. This combines the characteristic properties of a silicon photodiode with those of a low-noise CMOS diode array. The BiTec sensor guarantees precise photometric and spectral-radiometric measurement values over a large dynamic range through mutual correction of the measurement signals of both sensors.
Silicon photodiode detector, fast and linear
When taking into account the dynamic range, linearity and speed, silicon photodiodes have always been and are still the ultimate light detectors. A photometric corrected silicon photodiode is therefore incorporated in the BiTec light sensor of the BTS256-E light meter. Its matching to the photometric V(λ) responsivity is improved by the diode array’s spectral measurement data.
Diode array detector for spectral measurement data
The CMOS diode array of the BiTec Light sensor provides precise measurement data required for the luminous spectrum. This data is then used for calculation of the color values and scotopic illuminance as well as for optimization of the photometric responsivity.
Optimized signal to noise ratio
The noise signal from diode array detectors has significant effect on the signal to noise ratio (SNR) and hence on the quality of the measurement signal as well. A remote controlled shutter in the BiTec light sensor enables online compensation of the dark signals that are dependent on the temperature and integration time.
Pulse Width Modulated (PWM) LED lamps
The fast photodiode of the BiTec light sensor enables the BTS256-E to automatically synchronize itself to the frequency of lamps operated in PWM mode.