Extech Instruments HD450 User Manual page 4

Maximum (MAX) and Minimum (MIN) Reading Memory
The MAX-MIN function allows the meter to store the highest (MAX) and lowest (MIN) readings.
1. Press the MAX-MIN button to activate the feature. "Manu" and "MAX" will appear on the
display and the meter will only display the highest reading encountered.
2. Press the MAX-MIN button again. "Manu" and "MIN' will appear on the display and the meter
will only display the lowest reading encountered.
3. When the MAX or MIN has been captured, the value and associated time will remain in the
display until a higher value is recorded. The bargraph display will remain active displaying the
current light level.
4. To exit this mode and return to the normal operating mode, press the MAX-MIN button a third
time.
Relative Mode
The Relative Mode function allows the user to store a reference value in the meter. All displayed
readings will be relative to the stored reading.
1. Take the measurement, and when the desired reference value is displayed, press the REL
button.
2. "Manu" will appear on the LCD display.
3. All subsequent readings will be offset by the by an amount equal to the reference level. For
example, if the reference level is 100 Lux, all subsequent readings will equal the actual reading
minus 100 Lux.
4. To exit the Relative Mode, press the REL button.
LCD Backlight
The meter is equipped with a backlight feature that lights up the LCD display.
1. Press the backlight button
2. Press the backlight button again to switch the backlight off. Note that the backlight will turn off
automatically after a short period of time in order to save battery energy.
3. The backlight function uses extra battery energy. To conserve energy, use the backlight
feature sparingly.
to activate the backlight.
4 HD450-EU-EN V1.5 07/13