Signal Generation; Signal Processing - Landis+Gyr E450 User Manual

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Power supply
Memory
1.5.2

Signal Generation

1.5.3

Signal Processing

Calibration
Start detection
Measured quantities
Measurement
channels
© Landis+Gyr
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.
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.
I
Phase
U
Fig. 1.3 Measurement block diagram
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:
Direction:
Instantaneous Values:
There are 5 independent measurement channels. Each of the measured
quantities is assigned to one of these channels.
A DFS
D
A
D
Digital Multiplier
kWh, kvarh, kVAh
Import, export, ± reactive
Voltage, current, frequency, active power, power
factor
D000029326 en g – E450 PLC 1-phase ZCX100Px – User Manual
Description of Unit
Test-
output
Pulse
generator
Micro-
processor
Phase