User Manual

LT40-EN v1.3 9/13

MAX/MIN Button

The meter can record the maximum, minimum, and average readings as described below:

1. Momentarily press the “MAX/MIN” button and the meter will begin to track the

maximum/average/minimum measurements; the “MAX” icon will display at the top of the

LCD window indicating that the meter is now showing the maximum reading. The reading

will not change until a higher reading is registered.

2. Press the “MAX/MIN” button again to switch from “MAX” to “AVG”, where the meter will

show the average measurement value. The “AVG” icon will be displayed above the displayed

value.

3. Press the “MAX/MIN” button again to change the mode from “AVG” to “MIN”, where the

meter will show the minimum value measured. The “MIN” icon will be displayed.

4. Press the “MAX/MIN” button again to switch from “MIN” back to “MAX”.

5. To exit this mode, hold the “MAX/MIN” button for at least 2 seconds. The MAX/AVG/MIN

icons should all be switched OFF when the unit returns to the normal operating mode.

Data ‘Hold’ Button

Press the HOLD button to freezes the current reading on the LCD. Press the HOLD button again

to release the reading.

CALIBRATION and ZERO Buttons

1000 LUX Calibration

1. Prepare a 2856

K/1000 Lux light source and face the meter’s sensor perpendicularly

toward the light source.

2. Simultaneously press and hold both the “CAL/ZERO” button and the power button for at

least 2 seconds.

3. Release the buttons when “CAL” is displayed on the LCD screen.

4. Press and hold the “CAL” button for 2 more seconds, and the LT40 will power down.

5. The meter is now calibrated.

ZERO Calibration

1. Ensure that the protective cover is attached to the light sensor.

2. Power the meter and the LCD should display ‘0’.

3. Momenarily press the “ZERO” button for the zero adjustment and the CAL icon will

switch ON.

4. The CAL icon will switch OFF when the calibration has been completed.

5. If the protective cap is not covering the sensor when the ZEO calibration is started the

LCD display will read “CAP”. In this case, please cover the sensor with the cap and restart

this procedure.