Null Measurements - Agilent Technologies L34410A User Manual

The first four readings are taken on the 1 Vdc range, but the autoranging
feature switches to the 10 Vdc range for the final reading, which is a 20
percent overload for the 1 Vdc range. This is a typical 6½ digit behavior.
For frequency measurements only, the 34410A/11A/L4411A is capable of
displaying a full seven digits (for example, "999.980,3 HZ").

Null Measurements

The 34410A/11A/L4411A allows separate null settings to be saved for each of
the following measurement functions: dc voltage, ac voltage, dc current,
ac current, resistance, frequency/period, capacitance, and temperature.
When making null (also called relative) measurements, each reading is the
difference between a stored (selected or measured) null value and the input
signal. One possible application is to increase accuracy of two–wire resistance
measurements by nulling the test lead resistance. Nulling the leads is
particularly important prior to making capacitance measurements. The
formula used for calculating null measurements is:
• The null value is adjustable, and you can set it to any value between
• Front Panel Operation: For any measurement function, you can directly
• Remote Interface Operation: The following command enables the null
34410A/11A/L4411A User's Guide
Result = reading – null value
0 and ±120% of the highest range, for the present function. Note that the
null value is entered in fundamental units (for example, Vdc).
measure and store the null value by pressing
(nulls the test lead capacitance), shorted (nulls the test lead resistance), or
across a desired null value circuit.
Alternately, you can enable null from the menu. Press
...
> NULL > ON > NULL VALUE
Enter the desired null value with the navigation keypad, and then step
through or exit the menu. The Null annunciator is lit and the null function is
enabled.
To turn the null function off: Press
measurement feature for the specified function:
SENSe:< function >:NULL[:STATe] {ON>OFF}
where < function > is any function except CONTinuity or DIODe.
Features and Functions
with the test leads open
as required:
again, or use the menu.
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