Extech Instruments LT45 User Manual page 6

Luminous Intensity (CD) Measurements
1. Press the On/Off button to turn power ON.
2. Press and hold the LX/FC/CD button until the meter's unit designator switches to CD.
3. Use the arrow buttons to select ft (feet) or m (meter) units to represent the distance the
sensor will be from the light source.
4. Momentarily press the LX/FC/CD button; the smaller digits (lower‐right hand corner of LCD)
will switch ON, these digits represent the distance to the light source.
5. Use the arrow buttons to set the distance from the center of the lamp to the measurement
base level. Press and hold an arrow button to scroll quickly.
6. Momentarily press the LX/FC/CD button.
7. Remove the protective sensor cap and place the sensor perpendicular to the light at the
programmed distance.
8. Read the Luminous Intensity calculation on the meter's LCD display.
9. Press and hold the LX/FC/CD button to exit this mode.
 Luminous Intensity = illumination (Lx) x distance (ft
 The programmable distance range is 0.01 ~ 30.47 m (0.01 ~ 99.99 ft.)
Light Source (L.S.) Selection
There are 10 light source selections (L0 – L9) each having a unique calibration correction factor
(multiplier). See the Light Source Factors list below. The multipliers for locations L0 through L6
are fixed for the lighting types listed. Locations L7 through L9 are extra locations that the user
can customize (with a multiplier from 0.001 to 1.999). To change the light source (L.S.) selection:
1. Press and hold the Hold/LS button for 2 seconds. The light source code, at the bottom center
of the LCD, will flash. Use the arrow buttons to select L0 through L9. The location's multiplier
(correction factor) will be shown to the right of the Lx value (L8...1000, for example).
2. To customize a location, select L7, L8 or L9 and, once selected, momentarily press the
Hold/LS button to enter the multiplier programming mode. Now use the arrow keys to
change the multiplier. Press and hold an arrow button to scroll faster.
3. When finished, press and hold the Hold/LS button for at least 1 second to confirm the edit
and exit this mode.
Light Source Factors
L0: Standard light source: 1.00.
L1: LED white daylight: 0.99.
L2: LED RED light: 0.516.
L3: LED AMBER (YELLOW) light: 0.815.
L4: LED GREEN light: 1.216.
L5: LED BLUE light: 1.475.
L6: LED PURPLE light: 1.148.
L7~L9: Programmable User Custom Locations (preset to 1.00)
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