HP 34401A User Manual page 67

Chapter 3 Features and Functions
Math Operations
Null (Relative) The null value is stored in the multimeter's Null Register. There are
two ways you can specify the null value. First, you can enter a
(continued)
specific number into the register from the front-panel menu or from
the remote interface. Any previously stored value is replaced with the
new value. If you are operating the multimeter from the front panel,
entering a null value also turns on the null function.
The second way to enter the null value is to let the multimeter store
the first reading in the register. After you enable null, the first
reading displayed will be zero (if you have not changed the value
stored in the register). If you entered a number into the register, as
described in the paragraph above, the first reading does not overwrite
the stored value.
Front-Panel Operation: After enabling null, you can edit the stored
null value by pressing
stored value is replaced with the new value. Turning on the menu
does not disable the null operation; the multimeter will resume
taking measurements when you turn off the menu.
See also "To Make Null (Relative) Measurements," on page 38.
Remote Interface Operation: You can use the following commands to
make null measurements. Math must be enabled before you can store
a value in the Null Register.
The following program segment shows the proper order that you
should execute the commands to enable null and set an offset value.
66
Shift >
2: NULL VALUE (MATH MENU)
CALCulate:FUNCtion NULL
CALCulate:STATe {OFF|ON}
CALCulate:NULL:OFFSet {<
CALC:FUNC NULL
CALC:STAT ON
CALC:NULL:OFFS -2.0
(Menu Recall). Any previously
value
>|MINimum|MAXimum}