Keithley 2450 User Manual

Section
8: TSP command reference Model 2450 Interactive SourceMeter® Instrument
Reference Manual
8-116 2450-901-01 Rev. B/September 2013
smu.measure.nplc
This command sets the time that the input signal is measured for the selected function.
Type TSP-Link accessible Affected by Where saved Default value
Attribute (RW) Yes
Restore configuration
Instrument reset
Power cycle
Measure configuration list
Function change
Configuration script
Measure configuration list
1.0
Usage
nplc = smu.measure.nplc
smu.measure.nplc = nplc
nplc
The number of power line cycles; set from 0.01 to 10
Details
This command sets the amount of time that the input signal is measured.
The amount of time is specified in parameters that are based on the number of power line cycles (NPLCs). Each
PLC for 60 Hz is 16.67 ms (1/60) and each PLC for 50 Hz is 20 ms (1/50).
This command is set for the measurement of specific functions (current, resistance, or voltage).
The shortest amount of time (0.01 PLC) results in the fastest reading rate, but increases the reading noise and
decreases the number of usable digits.
The longest amount of time (10 PLC) 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.
Example
smu.measure.func = smu.FUNC_DC_VOLTAGE
smu.measure.nplc = 0.5
Sets the measurement time to 0.0083 (0.5/60)
seconds.
Also see
Using NPLCs to adjust speed and accuracy (on page 4-8)

Keithley 2450 Specifications

General

Model	2450
Category	SourceMeter
Voltage Source Range	±200 V
Current Source Range	±1 A
DC Voltage	200 V
DC Current	1 A
Power Output	20 W
Resolution	6.5 digits
Display	5-inch capacitive touchscreen
Operating Temperature	0°C to 50°C
Connectivity	USB, LAN, GPIB
Dimensions	213 mm × 88 mm × 370 mm