Extech Instruments 421504 Instruction Manual page 5

NOTE: Keep in mind that the main displayed value is either the Min, Max, or Avg
reading depending upon which icon appears on the LCD. Cycle through Min/Max/Avg
with the "MIN/MAX" key. Each value for MIN/MAX/AVG has an associated time value
(3rd display) memorized to tell the user when a peak or valley has occurred.
The Min/Max/Avg mode cancels the Auto Power OFF feature, disables most of the
meter keys, and will not allow a manual power OFF. Press and hold the MIN/MAX key
for several seconds to cancel Min/Max/Avg mode and return to normal operation.
5.8 Relative Mode (REL) for Main Display Only
The Relative Mode permits the user to store the current temperature value (or enter one
manually - see Set Mode) and compare it to subsequent temperature readings. In
Relative mode display indicates: Actual temp. minus Relative temp. = Displayed
temperature). To enter this mode press the "REL" key; The REL icon will appear on the
LCD and the temperature display shows zero (indicating that the actual temp. and
relative temp. are the same). Press the REL key again to exit the REL Mode. To display
the difference between the actual temperature and a manually entered Relative value,
press the SET key (see SET mode below).
5.9 Real-Time/Elapsed Timer Clock
The Timer (third display on bottom right of LCD) displays Clock or Elapsed Time and is
a convenient way to see when Min and Max temperatures occurred. Each time new Min
or Max temperature values are stored, the timer/clock value for the that Max or Min
temperature is also stored for later recall. Real time can be entered by setting the
meter's clock to the current time. To use the clock as an elapsed timer, first reset the
clock to zero in Set Mode (see next section).
5.10 SET Mode (for Relative Mode, HI/LO Alarm setpoints, and Clock/Timer
settings)
5.10.1 Manually setting the Relative Values in SET Mode
Press the "SET" key once and the display will show all dashes "======". Enter the
relative value using the meter's keys which double as numeric keys. Once the
Relative value is entered, press the ENTER key FOUR times to return to normal
operation. Now when the Relative Mode is activated, the Meter will display Actual
Temperature minus Relative Temperature.
5.10.2 Setting the Timer/Clock in SET Mode
Press the "SET" key and then the "ENTER" key. Next key in the Hours, Minutes,
and Seconds (HH:MM:SS) via the overlay numeric keys. When editing is complete,
the clock will begin counting. Press the "ENTER" key three times to return to
normal meter operation.
5.10.3 Alarm HI/LO Limit Programming in SET Mode
Press the "SET" key once and then the "ENTER" key twice. Key in the desired HI
Alarm value (high temperature at which the meter will audibly alert the user) via the
overlay numeric keys.(Alarm values are 4 number digits. 80° should be entered as
0080; 100° as 0100). Now press the "ENTER" key once. Next, key in the LO
Alarm Limit value (low temperature at which the meter audibly alerts the user).
Press the ENTER key once to return to normal operation and the alarms will be
armed giving an audible alert when a limit is reached.
5 421504 Ver. 1.8 01/03