52 Function Description
WAGO-I/O-SYSTEM 750 XTR
750-495/040-00x 3-Phase Power Measurement Module 690 V
Manual
Version 1.2.0
The values for the energy meters can be set via WAGO-I/O-
CHECK
. More
information on this is given in the section “Commissioning.”
The I/O module also allows you to set thresholds for energy measurement, i.e.,
energy is not metered until these start values settings are reached. This
threshold can be defined for each type of energy using WAGO-I/O-
CHECK
or
parameters 40, 41 and 42. More information on this is given in the section
“‘Module’ Tab.”
You can also define the storing interval using WAGO-I/O-
CHECK
or Register 46
in which the energy meter values are saved internally. The valid range for this is
60 … 255 s. With a storage interval of 60 s, the lifetime of the internal meters is
around 19 years. Each second added to this time increases the lifetime by about
0.3 years.
Determining the frequency
The phase frequencies are calculated using zero crossing detection of the
sampled signals for each phase. The minimum and maximum frequencies are
determined over a configurable time period (WAGO-I/O-
CHECK
or parameters
37, 38 and 39).
Harmonic analysis
Meaning of “upper harmonic”
“First harmonic” refers to the vibration at the fundamental frequency
(fundamental component), and “first
upper
harmonic” refers the vibration at twice
the fundamental frequency. Therefore, in general, the
n
th harmonic corresponds
to the (
n−1
)th upper harmonic.
The I/O module calculates the frequency spectrum for the periodic input signals
and analyzes the fundamental component and the first to 40th upper harmonics
for each phase, i.e. the first to 41st harmonics. This analysis can be performed
on one of the 3 phases (L1, L2 or L3).
The I/O module always yields the RMS values for current and voltage of the
fundamental component for the selected phase. It also provides the total
harmonic distortion (THD) for current and voltage.
From the 40 upper harmonics, 3 can be selected and analyzed at the same time.
The RMS value for current and voltage is calculated for each selected upper
harmonic, along with the harmonic distortion (HD). The 3 upper harmonics can
be freely selected, e.g., 4, 12 and 19, or 2, 35 and 40.