YASKAWA VIPA System SLIO Manual page 311

VIPA System SLIO
Voltage measurement
Current measurement
Calculating power, energy
HB300 | SM-AIO | | en | 17-05
Averaging
1. The square of the voltage measurement is calculated.
ð Vx 2
2.
2
The sum of Vx is calculated via the time interval n = 0 ... n = N-1.
2
ð Vx _SUM
3.
Vx 2 _SUM is divided by N the number of measurements.
4. From the result of the division, the square root is drawn.
ð AverageVx_RMS
For current measurement you have to use external current transformers!
CAUTION!
Use current transformer with max. 1A!
You may only use current transformer with max. current of 1A! Please
consider the data sheet of your current transformer!
CAUTION!
Note characteristics of current transformers!
– Please consider the data sheet of your current transformer!
– Some current transformer must not be operated in idle mode!
– Before commissioning your module must be connected to the secon-
dary winding of the current transformer!
– Please note that the overall accuracy of the assembly of measuring
module and current transformers depends on the accuracy class of
the transformers.
– The transformer factor is retentive stored and taken into account
while counting.
– A change of the transformer factor is taken immediately recognized.
Current counter values are not changed, new values are added.
– When the transformer factor was changed, current counter values are
not changed, new values are added considering the new factor.
To calculate the effective power P, each time synchronous sample value of the currents
and voltages are used. In this case, phase shifts between the currents and voltages are
considered. The energy is calculated from integration of the power by time.
For the power is valid:
– Positive sign (+): Consumed respectively received power
– Negative sign (-): Fed in power
031-1PA00 - AI1x 3Ph 230/400V 1A > Basics
Analog Input
311