6 General Operation
This sectionexplains basic operation of the 1502A Thermometer.

6.1 Selecting Units

Temperaturecan be displayed in degrees Celsius (indicated with “C”), degrees
Fahrenheit(indicated with “F”), or Kelvin(indicated with “A” fo r absolute).
The resistanceof the sensor can also be displayed (indicated with “o”for
ohms). Simplypress the appropriate unit button, C, F, K, or Ωto select the
units.

6.2 Parameter Menus

Except for unit selection, all functions and operating parameters are accessed
and edited withinthe parameter menus. There are four menus:the Probe pa-
rameter menu, Sample parametermenu, Comm (communication) parameter
menu, and Cal (calibration)parameter menu. The arrangement of parameters in
themenus is shown in Figure 4 on page 16.
Menus are selected by pressing theMenu/Enter button fo llowedby the ap pro-
priatemenu selection button. The name of the menu will briefly appear on the
display.For example, the Probe menu is selected by pressing the Menu/Enter
button (“SEt?” appears on the display)followed by the C/Probe button
(“ProbE” appears). Selecting the Cal menu requires that you press the
Menu/Enter button then press the Ω/Exit buttonand hold it down for at least
one second.
The Probemenu contains parameters for selecting the probe characterization
and setting the characterization coefficients.These parameters are explained in
Section6.4.TheSamplemenu contains parameters for setting the filter and ex-
citationcurrent. These are explained in Sections 6.5 and6.6. The Comm menu
contains communication parameters such as the serial baud rate or IEEE-488
address. These areexplained in Sections 7.1 and 7.2. The Cal menu contains
the calibration parameters. These are explainedin Section 8.1.

6.3 Menu Lockout

Allmenus can be locked out to prevent inadvertently changing parameters. By
default,only the Cal menu is locked out. The lockout option is accessed in the
Cal menu (see Section 8.1 “Accessingthe Calibration Parameters”).
If menus are lockedout you must enter the correct password (“2051”) to gain
access. After you select the menu (see the previoussection) the d isplay will
show“PA= 0000”and allow you to change the number to the correct pass-
word. Use the Land Rbuttons to move between the password digits and
the Uand Dbuttonsto increaseor decrease the value of a digit. Press Enter
15
6 General Operation
Selecting Units