Operation - Extech Instruments HD450-NIST User Manual

Operation

Meter Power
1. Press the Power button
2. If the meter does not switch on when the power button is pressed or if the low battery icon is
displayed on the LCD, replace the battery.
Auto Power Off (APO)
1. The meter is equipped with an automatic power off (APO) feature that turns the meter off after
20 minutes of inactivity. The
2. To disable the APO feature, simultaneously press and release the RANGE/APO and
REC/SETUP buttons. Press and release again to re-activate the APO feature.
Unit of Measure
Press the UNITS button to change the unit of measure from Lux to Fc or from Fc to Lux
Range Selection
Press the RANGE button to select the measurement range. There are four (range) selections for
each unit of measure. The range icons will appear to identify the range selected.
Taking a Measurement
1. Remove the sensor's protective cap to expose the white sensor dome
2. Place the sensor in a horizontal position under the source of light to be measured
3. Read the light level on the LCD display (numerically or with the bargraph).
4. The meter will display 'OL' when the measurement is outside of the meter's specified range or if
the meter is set to the wrong range. Change the range by pressing the RANGE button to find
the best range for the application.
5. Replace the protective sensor cap when the meter is not in use.
Data Hold
To freeze the LCD display, momentarily press the HOLD button. 'MANU HOLD' will appear on the
LCD. Momentarily press the HOLD button again to return to normal operation.
Peak Hold
The Peak Hold function allows the meter to capture short duration light flashes. The meter can
capture peaks down to 10mS in duration.
1. Press the PEAK button to activate the Peak Hold feature. "Manu" and "Pmax'' will appear on
the display. Press the PEAK button again and "Manu" and "Pmin" will appear. Use 'Pmax' to
capture positive peaks. Use 'Pmin' to capture negative peaks.
2. When the peak has been captured, the value and associated time will remain in the display
until a higher peak is recorded. The bargraph display will remain active displaying the current
light level.
3. To exit the Peak Hold mode and return to the normal operating mode, press the PEAK button a
third time.
to turn the meter ON or OFF
icon appears while APO is enabled.
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