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Description of Unit
© Gyr
D000029326 en g – E450 PLC 1-phase ZCX100Px – User Manual
The supply voltage for the meter electronics is taken from the single-phase
system. In the event of mains failure a voltage monitor ensures the safe
storage of meter data and manages the restart when mains voltage is re-
stored.
Meter parameters are stored in non volatile (FLASH) memory which pro-
tects the parameters in the event of power failure.
1.5.2
Signal Generation
The DFS (Direct Field Sensor based on embedded coil measuring princi-
ple) measuring element measures the phase current using the magnetic
field of the current loop, and the phase voltage over a resistor divider. The
analogue/digital converters transform both signals into digital voltage and
current data. This data is then multiplied by a digital multiplier to produce an
energy proportional value which is then transferred into the energy
registers
(rate-dependent)
.
The microprocessor generates pulses for the test diode from the digital
value according to the meter constant R.
Micro-
processor
Test-
output
Phase
DFS
I
U
Phase
A
D
A
D
Digital Multiplier
Pulse
generator
Fig. 1.3 Measurement block diagram
1.5.3
Signal Processing
The output value of the DFS is used as a basis for further calculations.
The measurement system is calibrated during the manufacturing process of
the meter. Calibration data is stored in a non-volatile memory and cannot
be altered.
The microprocessor compares the measured power with the minimum
starting power. Signals are only processed if the minimum starting power is
exceeded.
The following energy values can be measured and stored in the registers:
•
Active energy (A)
•
Reactive energy (R)
•
Apparent energy (VA)
Energy type:
kWh, kvarh, kVAh
Direction:
Import, export, ± reactive
Instantaneous Values:
Voltage, current, frequency, active power, power
factor
There are 5 independent measurement channels. Each of the measured
quantities is assigned to one of these channels.
Power supply
Memory
Calibration
Start detection
Measured quantities
Measurement
channels
