Ametek California Instruments MX15 Series User Manual page 95

4.5.2 3Pi Controller Measurements
For MX Series with the -1Pi controller, the following four measurement screens are available:
Mode
V OLTA GE
CURRENT
FREQUENCY
POW ER
V A POW ER
PEA K CURR
POW ER FA CT
CREST FA CT
V OLT THD
CURR THD
INST PK CURR
PHA SE
Note: The V and I distortion calculations are based on H2 through H50 with the RMS current in
the denominator. Note that some definitions of THD use the fundamental component (H1) as the
denominator. This may result in different readings between instruments depending on the
implementation chosen.
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. This process may take up to a second. 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.
The measurement method for voltage and current will depend on the power source's operating
mode. The following table shows the return value type (rms or average) and method of coupling
when the measurement command is initiated with a different extension at various operating
modes (AC, DC or AC + DC).
Measurement
Extension and
Coupling
Coupling
4.5.3 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 MX Series is a high power AC and DC
source optimized for providing and measuring high load currents. When powering low power
MX15 Series
AC
MEASUREMENTS 1
A C rms voltage
A C rms current
Frequency
Real power
MEASUREMENTS 2
A pparent power
Highest A C current found
Power factor
Crest factor
MEASUREMENTS 3
V oltage distortion
Current distortion
Instantaneous peak current
Phase angle
AC
A C rms
DC rms
A C
DC
DC V oltage
DC Current
n/a
n/a
power
Highest DC current found
n/a
n/a
n/a
n/a
Highest DC current found
n/a
Operating Mode
DC AC + DC
rms
rms average
DC
AC+DC
A C rms voltage
A C rms current
Frequency
n/a
A pparent power
Highest A C current found
Power factor
Crest factor
V oltage distortion
Current distortion
Instantaneous peak
current
Phase angle
rms
DC
95