General Tools and Instruments DLAF8000C - Manual (Page 9)

Zero Offset Adjustment of Light Function :
*
For best results zero the light sensor prior to use in a
dark environment. Placing the light sensor end of the
meter under a desktop or flat surface so as to block
any light can accomplish this. Then press the
"Unit/Zero Button" ( 3-4, fig. 1 ) to set the meter
indication to zero.
*
Zero point can drift due to environment temperature
and battery power change as well as for other reasons.
It is recommended that the zero be checked
frequently using the above procedure.
5. OTHER FUNCTIONS
5-1 Hold Function
Whenever press the "Hold Button (3-2, Fig. 1)" will freeze
the current reading value with a "HOLD" symbol on the
display.
5-2 Data Record Function
1) The Data Record function records & displays the maximum
and minimum reading values. Start the Data Record function
by pressing the " Max./Min. Button " ( 3-3, Fig. 1 ) once.
There will be a " REC " symbol on the display.
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