AMETEK Lx Series II User Manual
Page 101
User Manual
Lx / Ls Series II
97
4.5 Measurements
Standard measurements are always available through the Meas key on the front panel. These
measurements are spread across multiple screens to enhance readability. Switching between
these screens can be done by successively pressing the Meas button on the front panel. This will
cause the screen to cycle through all available measurement screens.
4.5.1 Basic Measurements
The following three measurement screens are available:
Parameter
MEASUREMENTS 1
VOLTAGE
AC rms voltage
CURRENT
AC rms current
FREQUENCY
Frequency
POWER
Real power
MEASUREMENTS 2
VA POWER
Apparent power
PEAK CURR
Repetitive Peak Current
POWER FACT
Power factor
CREST FACT
Crest factor
MEASUREMENTS 3
VOLT THD
Voltage distortion
CURR THD
Current distortion
PEAK CURR
Highest AC current found (Track and hold)
PHASE
Phase angle (relative to phase A (ø1)
Note: The V and I distortion calculations are based on H2 through H50 with the fundamental
component (H1) in the denominator.
Measurements are always running in the background. When the user selects a measurement
screen for display, the AC source first updates all the measurement parameters before
displaying the requested screen. Consequently, pressing the MEAS key may not always bring up
the selected screen immediately. There will be a perceptible delay. This will prevent the screen
from appearing with invalid or blank readouts.
Note that all measurements are AC coupled only so any DC offset will not be reported.
4.5.2 Accuracy Considerations
Any measurement system has a finite accuracy specification. Measurement specifications are
listed in Section 2. When using the AC source for measurement purposes, always consider these
specifications when interpreting results. Measurement inaccuracies become more pronounced
as the signal being measured is at the low end of the measurement range. This is particularly
relevant for low current measurements. The Lx/Ls Series is a high power AC source optimized
for providing and measuring high load currents. When powering low power loads, measurement
inaccuracies on rms and peak current measurements will greatly affect derived measurements
such as power, power factor and crest factor.
The measurement system on the Lx Series uses a digital data acquisition system with a 96
Ks/sec sampling rate and 16 KHz bandwidth. This means that higher frequency components of
the measured signal are filtered out. Any contribution to the rms value of voltage and current