Delta LTL2000S - Manual (Page 31)

DELTA LTL2000S(Q) Retroreflectometer 27
mild household detergent.
To ensure reliable measurements, it is recommended that the calibration unit is periodically
recalibrated to a traceable standard. DELTA Light & Optics offers calibration traceable to
PTB (Physikalsich-Technishe Bundesanstalt). For information contact your distributor or
DELTA Light & Optics.
Light trap
Zero signals are simulated by a light trap made of two glossy and black plastic sheets moun-
ted in an acute angle. If clean this will provide very efficient light absorbing device.
Figure 10. Light trap
It is necessary to disassemble the light trap to clean it efficiently. This is easily done by lifting
and pulling it. Cleaning can be done by using a fine brush, clean pressurised air or a soft paper
tissue/cloth and some window cleaning liquid.
Figure 11. Cleaning lighttrap-plate.
Light trap
Rl calibration unit
Pull and lift the upper
lighttrap-plate for
cleaning.