Metrix CX 1651 User Manual

119
Grounding of the calibrator and the instrument to be calibrated in the P-E mode
When calibrating the power and energy meters with separate voltage and current circuits, it is
advisable to select GND U ON and GND I ON (both grounding methods on) on the CX 1651
calibrator. This setting will ground both the current and voltage output of the calibrator.
If the instrument to be calibrated has electrically connected and not grounded current and voltage
inputs, GND U ON and GND I OFF should be selected on the CX 1651 calibrator.
If Lo and -I terminals on the calibrator are connected AND the same terminals are connected at the
instrument to be calibrated, resulting voltage drop at the current cables can damage the relay which
interconnects Lo and -I terminals with GND terminal in the calibrator.
“Operating examples“ chapter provides more information concerning correct connection of powermeters
and energy meters to the calibrator.
18.13.5. Uncertainty calculation of set power
Uncertainty of set power displayed on the Accuracy line of the display is calculated according to the following
formula:
for active power d P = √ ( dU
2
+ dI
2
+ dPF
2
+ 0.03
2
) [%]
for reactive power d P = √ ( dU
2
+ dI
2
+ dPF*
2
+ 0.03
2
) [%]
for apparent power d P = √ ( dU
2
+ dI
2
+ 0.03
2
) [%]
where dP is the uncertainty of set power [%]
dU is the uncertainty of set voltage [%]
dI is the uncertainty of set current [%]
dPF is the uncertainty of set PF (cosϕ) [%]
dPF* is the uncertainty of set sinϕ [%]
18.14. Generation of frequency
The multifunction calibrator can generate several different voltage shapes with exact frequency, amplitude and
duty cycle. The output signal is present at BNC coaxial connector FREQ located at the front panel. The signal
is not present at any other output terminal.
There are two frequency generation modes. The first mode (PWM) allows the generation of squarewave output
signal with calibrated amplitude, frequency and duty cycle. Frequency range is up to 10 kHz. The second mode
(HF) also provides squarewave output signal with very steep rising edge, typically less than 3 ns.
PWM mode
Frequency range: 0.1 Hz to 100 kHz
Voltage range: 1 mV to 10 Vpp
Signal shapes: squarewave, negative PWM NEG – symmetrical PWM SYM – positive PWM
POS
HF mode
Frequency range: 0.1 Hz to 20 MHz
Voltage range: 5 Vpk-pk 0, -10, -20, -30 dB
Signal shapes: symmetrical squarewave
PWM mode can be used to calibrate the input sensitivity of oscilloscopes at frequencies up to 10 kHz. HF
mode can be used to calibrate the time base of oscilloscopes.

Metrix CX 1651 Specifications

General

Brand	Metrix
Model	CX 1651
Category	Test Equipment
Language	English