Keithley 2461 Reference Manual

Section
9: Frequently asked questions (FAQs) Model 2461 Interactive SourceMeter® Instrument
Reference Manual
9-10 2461-901-01 A/November 2015
What is NPLC?
You can adjust the amount of time that the input signal is measured. Adjustments to the amount of
time affect the usable measurement resolution, the amount of reading noise, and the reading rate of
the instrument.
The amount of time is specified in parameters that are based on the number of power line cycles
(NPLCs). Each power line cycle for 60 Hz is 16.67 ms (1/60); for 50 Hz, it is 20 ms (1/50).
The shortest amount of time results in the fastest reading rate, but increases the reading noise and
decreases the number of usable digits.
The longest amount of time provides the lowest reading noise and more usable digits, but has the
slowest reading rate.
Settings between the fastest and slowest number of PLCs are a compromise between speed and
noise.
If you change the PLCs, you may want to adjust the displayed digits to reflect the change in usable
digits.
What are the Quick Setup options?
The QUICKSET key opens a screen that provides access to function selection, performance
adjustments, and quick setups.
The Function button on the Quickset menu allows you to select a source or measure function. The
options are the same as those available when you use the front-panel FUNCTION key.
The Performance slider allows you to adjust speed and resolution. As you increase speed, you lower
the amount of resolution. As you increase resolution, you decrease the reading speed. These settings
take effect the next time the output is turned on and measurements are made.
The Quick Setups allow you to set the instrument to operate as a Voltmeter, Ammeter, Ohmmeter, or
Power Supply.
When you select a Quick Setup, the instrument turns the output on. Carefully consider and configure
the appropriate output-off state, source, and limits before connecting the Model 2461 to a device that
can deliver energy, such as other voltage sources, batteries, capacitors, or solar cells. Configure the
settings that are recommended for the instrument before making connections to the device. Failure
to consider the output-off state, source, and limits may result in damage to the instrument or to the
device under test (DUT).

Keithley 2461 Specifications

General

Maximum Current	7 A
Power	100 W
Resolution	6.5 digits
Source Measure Unit (SMU)	Yes
DC Voltage	100 V
Maximum Voltage	100 V
Display	5-inch capacitive touchscreen
Connectivity	USB, GPIB
Software	TSP
DC Current	7 A
Current Source Range	0 to 7 A
Voltage Measurement Range	100 mV to 100 V
Current Measurement Range	10 nA to 7 A
Voltage Measurement Resolution	100 nV