Section 4: Measurement optimization
Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual
4-4
077114601 / March 2019
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 (0.002 PLCs) results in the fastest reading rate, but increases reading
noise and decreases the number of usable digits.
The longest amount of time (12 PLCs for 60 Hz and 15 PLCs for 50 Hz) provides the lowest reading
noise and more resolution, but has the slowest reading rate.
Settings between the fastest and slowest NPLCs are a compromise between speed and noise.
Figure 108: Speed vs. noise characteristic
After adjusting the speed, you may want to adjust the number of digits that are displayed for
(on page 4-6).
To set the number of power line cycles (NPLCs) using the front panel:
1. Select the measurement function. The NPLC settings will be applied to this function. For more
information, you can refer to
(on page 2-96).
2. Press the
MENU
key.
3. Under Measure, select
Settings
.
4. Next to NPLC, select the number. The NPLC window is displayed.
5. Enter the value and press the
ENTER
key.
