Agilent Technologies 34401A manual Null Relative Operation

Chapter 3 Features and Functions

Math Operations

•Remote Interface Operation: You can use the following commands to make min-max measurements.

CALCulate:FUNCtion AVERage
CALCulate:STATe {OFFON}	read the minimum value
CALCulate:AVERage:MINimum?
CALCulate:AVERage:MAXimum?	read the maximum value
CALCulate:AVERage:AVERage?	read the average of all readings
CALCulate:AVERage:COUNt?	read the count

A new command is available starting with firmware Revision 2 which allows you to take readings using INITiate without storing them in internal memory. This command may be useful with the min-max operation since it allows you to determine the average of a series of readings without storing the individual values.

DATA:FEED	RDG_STORE, ""	do not store readings
DATA:FEED	RDG_STORE, "CALCulate"	store readings (default)

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See page 126 for more information on using the DATA:FEED command.

Null (Relative) Operation

When making null measurements, also called relative, each reading is the difference between a stored null value and the input signal. One possible application is in making more accurate two-wire ohms measurements by nulling the test lead resistance.

Result = reading – null value

Applies to all measurement functions, except continuity, diode, and ratio.

•The null value is adjustable and you can set it to any value between 0 and ±120% of the highest range, for the present function.

•The null value is stored in volatile memory; the value is cleared when power has been off, after a remote interface reset, or after a function change.

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