L203 SMU Supplement Irradian Limited
5
SPOT LUMINANCE SETTING UP
1) Carefully screw the CIE-INT intermediate filter ring to the SMU203
telescope and the DET203Vis detector to the intermediate filter ring.
Remove the rear lens cap and screw either the 25, 50 or 75 mm 'C'
mount lens to the SMU (including any other optical components such
as a x2 converter or extension tube). If an extension tube is fitted
check the calibration certificate for the multiplication factor.
2) With the unit OFF, plug the detector 8 way connector into the socket
on the top of the display unit.
3) Press and release the power switch on the L203 display key pad. The
micro controller will initiate with the display momentarily showing:-
The radiometer will now search for the optimum range on the detector
amplifier. A typical display is shown below.
An LED will illuminate indicating the units. This will be the same units
prior to the last power off.
4) Press and release the UNITS switch to select the correct units for
luminance measurements. The correct setting will be one of cd.m
-2
, fL
or Aux as detailed on the calibration certificate, supplied with the
meter.
5) View the source to be measured by sighting through the eyepiece
viewer, noting that the size of the source must be greater than the dark
circle spot observed on the reflex mirror. Light sources that appear to
be totally obscured by the black spot will not be accurately measured.
In this case move toward the source until it overfills the spot.
