Handbuch-KnxSmartmeter-85A-en-3 odt, 2018-10-04 Seite 4 von 69
Function
The KNX Smartmeter is a bidirectional counter for measuring the active and reactive power or
energy, as well for power quality monitoring The measurement will be done in three-phase
system or in three separate single-phase systems with the accuracy of class 1 (1%)
In the accuracy class 1 according to EN 62053-31 only accuracy requirements for the
measurement range between 2% and 100% of rated current are determined For smaller
currents no requirements are defined, as these can not be accurately detected with conventional
current transformers In contrast, the Enertex KNX Smartmeter uses high precision (Rogowski-)
current sensors which are calibrated to the device in factory Thus, very small currents to
0 002% (2mA) of rated current are accurately measurable In addition, the current is measured
with very little loss (< 2mW loss) The provided current sensors are suitable for through-hole
mounting and can be installed directly at the main supply point of the grid
The Smartmeter is powered exclusively via the bus Therefore, the device can even be operated
if there is no voltage at the voltage inputs or the voltage has been separated
The measurement range of the active power extends from 0 5W to 19 550W or 58 650W (three-
phase) Energy values or measurement values for monitoring the power quality can be recorded
for analysis on a SD card
All measured values (current, voltage, active power, reactive power, active energy, reactive
energy, power factor, THD-U, THD-I, power harmonics, unbalanced load, zero current, power
frequency) are shown on the KNX bus
Besides specialized functions for performance-based load control, optimization of the inherent
energy demand with PV facilities, calculating the usage or feeding charge with tariff switching
the ETS application also provides various monitoring functions In case of exceed of limits these
functions report events as power outages, high voltage spikes, high power distortion, high
reactive energy, highly non-uniform loading of the three phases (unbalanced load) or high
neutral loading on the bus To assess the power quality harmonics up to the 50th harmonic of
current and voltage are measured The numerous monitoring features enable fast accurate
analysis of network-related failures, malfunctions and damages of electrical equipment
The device variant with the RT option can also be operated without a KNX bus To do this, a
24VDC power supply must be connected to the KNX terminal In this mode, all measurement
data of the recording mode "All measured values without mains harmonics" are recorded on the
SD card every minute as described in the section "Recording on the SD card" The recording
times for the measured values are selected in this mode according to an internal battery-
buffered clock, which is factory set to the local time of Berlin (UTC / GMT +1 hour) and deviates
from the real time by a maximum of one minute per year If necessary, the clock can be adjusted
using the SD card The adjustment of the clock without KNX bus is described in section
"Adjusting the real-time clock without bus access"
Note: The security against tampering of the current counter, required for billing purposes, can
not be guaranteed with this Smartmeter Therefore this KNX device is not a current counter for
billing purposes in terms of the standard (for example IEC 62052-11)
Technica specifications
KNX Voltage:
Current consumption:
Typical power consumption:
DC 21 32 V SELV
< 18mA
0 28W
Enertex® Bayern GmbH – Ebermannstädter Straße 8 - 91301 Forchheim - Deutschland - mail@enertex de
