–
number of ten-minute intervals in which average value of the 2
nd
to 25
th
har-
monic was higher than the value defined by the standard,
–
number of ten-minute intervals in which the THD for the 2
nd
to 40
th
harmonic
was higher than the value defined by the standard,
–
number of ten-minute intervals in which the average value of unbalance was
higher than the limit defined by the standard,
–
the number of 3 s mean values of voltage components with frequency of the rip-
ple control signal, which overpassed the limit defined by the standard, is being
recorded for each day of a compressed week.
3.5 Function of oscilloscopic measurements
The function of oscilloscopic measurements serves for checking the correct connec-
tion of the set the PQ monitor, the correct choice of measuring ranges and the correct
orientation of current sensors. A notebook with a series interface USBII is used for
displaying the shapes of voltages U1 to U4 and currents I1 to I4. The recording with
duration of 2 periods (40 ms) can be started case by case or repeatedly.
3.6 Communication function
The basic communication interface of the PQ monitor is a series interface USBII with
the data transmission rate up to 460.8 kbit/s. This enables to read out the content of
the 2 MB data memory during about 2 minutes. It is also possible to choose another
transmission rate (921.6 kbit/s).
Alternatively, the PQ monitors for fixed mounting can be ordered with interface
RS 232 or with another series interface according to the customer’s requirement
(RS485, …).
3.7 External input
The external input is a two-value one and it enables to connect DC and AC voltages
in the range of 24 V to 230 V. The decision making level is at 15 V. The external input
can generate an event without recording the detail of the event. The front edge or
the trailing edge of the voltage of the external input may be active depending on
programming.
8
PQ monitor – MEg30, MEg31, MEg32, MEg33
