Page 4 Model 421508 Version 1.0 October 2002
Meter Operation
Power Key
The Power key (red key) turns the thermometer ON or OFF. Note that in the MIN/MAX
record mode the thermometer cannot be powered off. Be sure to exit the MIN/MAX record
mode before powering off.
°C/°F Key
Readings can be displayed in degrees Celsius (°C) or degrees Fahrenheit (°F). Note that
the meter remembers the unit of measure when it is turned off. Press the °C/°F key to
change the temperature units. The C/F key is also the zero (0) key and the minus (-) key
for negative number entry (explained later in the ‘SET Key’ section).
HOLD Key (Main Display only)
Press the HOLD key to enter the Data Hold mode, the "HOLD" annunciator will display.
When HOLD is selected, the thermometer freezes the reading on the main display (the
main display is the center LCD line with the largest digits). Press the HOLD key again to
return to the normal measurement mode. In the MIN/MAX recording mode, use the HOLD
key as a pause/resume recording control. The HOLD key doubles as the ENTER key for
programming purposes.
T1 T2/T1-T2 Key - Main Display Input Selection
Note that this key doubles as the numeric ‘1’ key. Press this key to select which
thermocouple input configuration is represented on the main display; ‘T1’ will display for
thermocouple input 1, ‘T2’ for thermocouple 2, or ‘T1-T2’ for the difference between the
two thermocouple measurements.
Type Key - Thermocouple Type for T1
Note that this key doubles as the numeric ‘2’ key. Use the TYPE key to select the
thermocouple type (K, J, T, E, R, S, or N) that is connected to the T1 input. The
thermocouple type is indicated on the left side of the LCD. When the thermometer is turned
on, it remembers the type used when the thermometer was last turned off.
MIN MAX Key
Note: Auto Power OFF and several keys (C/F, REL, SET, HI/LO, TYPE, and T1 T2 T1-T2)
are defeated in this mode
Press MIN MAX to enter the MIN MAX recording mode; the meter will begin keeping track
of the highest (MAX), lowest (MIN), and Average (AVG) readings. There are four displays
(listed below) for this mode. Use the MIN MAX key to scroll through all four.
a. When the RECORD icon is on the display (top), the meter is displaying measurements
normally while it is recording.
b. With the RECORD MAX icon on the display, the meter continues taking measurements
but the main display shows only the highest (MAX) reading recorded. The Elapsed
Time (in hours, minutes, and seconds) is shown in the lower right LCD field. The Timer
shows when the MAX reading was taken.
c. With the RECORD MIN icon on the display, the main display shows only the lowest
reading recorded. The Time of the MIN reading is shown in the lower right LCD field.
d. With the RECORD AVG icon on the display, the main display shows only the average
of all the readings recorded. Note that the averaging limit is 22 hours. After 22 hours,
the last average reading display is held on the LCD.
The meter emits a tone when a new minimum or maximum value is recorded. Use the
HOLD key to pause recording (all values are then held). Press HOLD again to resume
recording. To exit the MIN MAX mode press and hold the MIN MAX key until the RECORD
icon switches off.
