Mega MEg40+ User manual

MEgA – Měřící Energetické Aparáty, a.s.MEgA – Měřící Energetické Aparáty, a.s.
664 31 Česká 390664 31 Česká 390
Czech RepublicCzech Republic
Universal Energy Meter
MEg40+

3
Universal Energy Meter MEg40+
Universal energy meter MEg40+
1/ PURPOSE AND DESCRIPTION
e universal energy meter MEg40+ works as an energy meter and a monitor at the same
time. In the function of the energy meter, it has a set of six energy registers for each phase.
In the function of the monitor, it records long-term voltage, current and power curves
and according to the voltage quality standard ČSN EN 50160 ed. 3, it registers voltage
deviations in class S. e values of energies and recorded quantities are shown on the
display. e instrument MEg40+ is designed for LV, MV and HV measurements.
For LV measurements, it is possible to use both the basic version and the version
MEg40+/S1, which uses split core instrument transformers SMART PTD to indirectly
measure currents. e version MEg40+/S3 uses exible current sensors AMOSm to measure
currents; this version can be installed in uninterrupted power supply technology PPN (live-
line working).1)
e universal energy meter MEg40+ is an instrument of the measurement category IV,
it is designed for installation in unprotected circuits of LV stations and substitutes classic
pointer registering instruments and also four-quadrant energy meters.
MEg40+ stores all measured data in the Flash data memory for further processing in PC
or PDA and archiving in database tools. e internal 4 MB data memory can be replaced
by a removable 16 MB memory card of special design that enables fast and on personnel
and technical means undemanding data transfer into information systems. e standard
communication interface of the instrument MEg40+ is USB 2.0. It is made also in versions
with the RS232 / RS485 interface that are used to integrate the instrument MEg40+ into
measuring systems. e USBhost / RS485 converter can be also additionally connected to
the instrument MEg40+ made with USB 2.0 interface.
e measuring modes and conversion constants of components of the measurement chain
can be programmed from the keyboard of the instrument or more comfortably using PC.
e user program of the instrument MEg40+ evaluates data of one instrument in PC. Data
measured by more instruments MEg40+ and archived in a database can be processed using
the system software WebDatOr. e user SW is described in the User manual MEg40+.
1) e versions of MEg40+/S1 and MEg40+/S3 are described in separate manuals.

Měřící Energetické Aparáty
4
2/ TECHNICAL PARAMETERS
Reference conditions: Usupply = 230 V / 50,0 Hz
ambient temperature = 20 °C, relative humidity = 40 % to 70 %.
Measured voltages and currents have a frequency identical with Usupply and make
athree-phase system.
Measured
quantity Rated value Range of measurement
Accuracy
[% of range] Note
TRMS voltage Unom = 230 V 0 V to 290 V 0.2 % ± 1 digit 1), 2)
Unom = 57.73 V 0 V to 125 V 0.2 % ± 1 digit
TRMS current Inom=1 A 0 A to 1.2 A 0.2 % ± 1 digit 1), 2),
3)
Inom=5 A 0 A to 6 A 0.2 % ± 1 digit
Power factor PF U > 0.8 Unom
I > 0.1 Inom
PF > 0.1 0.5 % ± 1 digit 4)
Active power 230 V / 5 A, 1 A PF > 0.4 0.5 % ± 1 digit 4)
Reactive power 230 V / 5 A, 1 A PF < 0.6 0.5 % ± 1 digit 4)
Active energy 230 V / 5 A
U ≥ 0.8 Unom
I > 0
Cos ϕ L > 0.5
Cos ϕ C > 0.8
Class B
according to
TPM 2440-08
ČMI
Voltage events Unom
0.05 Ujm to 1.20 Unom
T ≤ 1 sec
1.0 % Unom
20 msec 5), 6)
Notes:
¹ Only the range is to be specied in the order.
² e rated value of the primary quantity is to be entered using PC or from the
keyboard.
³ Only indirect current measurement through measuring current transformers. In
LV and MV networks, special measuring current split core transformers PTD with
the rated currents 100 A, 200 A, 300 A, 400 A, 500 A, 600 A and 900 A can be used.
 It measures in 4 quadrants.
 It evaluates events according to the voltage Urms1/2 specied in ČSN
EN 61000-4-30, ed. 2 with characteristics in ČSN EN 50160, ed. 3, i.e. with the
residual voltage and event duration.
 With an external uninterruptible power supply unit, e. g. MEg102, it can measure
longer voltage events.

5
Universal Energy Meter MEg40+
Frequency range of phase lock loop: 47.4 Hz to 52.9 Hz
Input impedance in 230 V range: 1.8 MΩ
in 57.7 V range: 0.9 MΩ
Maximum input phase voltage
in 230 V range: 295 Vef
in 57.7 V range: 150 Vef
Maximum voltage on current inputs at Inom
in 5 A range: 0.16 Vef
in 1 A range: 0.8 Vef
Overload capacity of current inputs: 1 min – 2 × Inom
1 sec – 30 × Inom
Allowable voltage between current inputs: 50 Vef
Supply voltage UAC supply: 230 V +10 %, –30 %
Spotřeba při UAC supply = 230 V: 5,0 VA
Quantities measured in MEg40+:
Phase voltage Active energy at consumption
Delta voltages Active energy at delivery
Phase currents Reactive energy L at consumption
Active and reactive powers Reactive energy L at delivery
U and I events Reactive energy C at consumption
Maximum currents Reactive energy C at delivery
Quantities calculated in PC : Quantities displayed on MEg40+:
True power factors - PF Phase/delta voltages
Daily current diagrams Phase currents
Statistics of events Active powers
General data
Flash data memory: 4 MB1)
Data memory organisation: linear or circular
Serial communication: USB2.0 / RS232 / RS4852)
Speed of serial communication (USB 2.0, RS485 and RS232):
115,2 kBd (default), 256 kBd when the measurement is stopped (USB 2.0 only)
Internal time: 1,0 sec / 24 hr., Tnetwork ± 1 sec at f network synchronization
Notes:
1) 16 MB when 16 MB memory card is used
2) One type of communication as ordered.

Měřící Energetické Aparáty
6
Construction
Dimensions body: 90 × 90 × 90 mm
frame: 95 × 95 mm
Weight: 0.6 kg
Terminal block: max  of wires 3.0 mm
Panel attachment: 2 pcs of removable eccentrics
Operating data
Working temperature: -25 °C to +55 °C
Storage temperature: -25 °C to +85 °C
Relative humidity: 20 % to 90 % at 40 °C
Ingress protection rating (IEC 60529): front panel IP40, other parts IP20
Pollution degree: 2
Measurement category: IV, Unom = 230 V
Battery type for internal time: Li battery CR ½ AA CD
Electromagnetic compatibility
Electrostatic discharge immunity: conforming to IEC 61000-4-2
(4 kV / 15 kV)
Immunity to radiated radio-frequency elds: conforming to IEC 61000-4-3
(10 V/m, 80 MHz - 2000 MHz)
Immunity to fast transients: conforming to IEC 61000-4-4 (2 kV)
Surge immunity: conforming to IEC 61000-4-5 (4 kV)
Immunity to induced voltages: conforming to IEC 61000-4-6 (3 V)
Immunity to dips, short interruptions: conforming to EN 61000-4-11
(1 period / 100 %)
Interference voltages conducted: conforming to EN 55011
Radiated emissions in the range 30-1000 MHz: conforming to EN 55011
Harmonic current emissions: conforming to EN 61000-3-2
Voltage changes, voltage and icker uctuations: conforming to EN 61000-3-3
Magnetic elds with f = 50 Hz, 0,5 mT: conforming to IEC 1036
External electric eld 50 Hz / 10 kV/m: conforming

7
Universal Energy Meter MEg40+
3/ FUNCTION DESCRIPTION
Compared with the original universal monitor MEg40, the universal energy meter
MEg40+ oers extended functions to measure electrical energy. When measuring energies,
it stores measured values into non-destructive registers and allows also additional creation
of tari bands and load proles, without limitation of their number and time. anks
to the possibility of subsequent analysis, MEg40+ can be used in locations with a set of
functionally independent consumptions unspecied in advance, e.g. in manufacturing
and commercial complexes.
e instrument MEg40+ has a set of six energy registers for each phase according to
standard IEC 62053-23, see Fig. 1. ey are the following registers:
OBIS: 1.1.1.8.0 EP+ - active energy, consumption
OBIS: 1.1.2.8.0 EP- - active energy, delivery
OBIS: 1.1.5.8.0 EQL/P+ - reactive energy inductive at consumption
OBIS: 1.1.7.8.0 EQL/P- - reactive energy inductive at delivery
OBIS: 1.1.8.8.0 EQC/P+ - reactive energy capacitive at consumption
OBIS: 1.1.6.8.0 EQC/P- - reactive energy capacitive at delivery
e set of six registers for an outlet is located in the basic non-destructive memory of the
instrument and the set of six distributed registers of the individual phases is located in the
data ash memory that can be realized as a memory card.
Fig. 1: Denition of quadrants of active and reactive energy according to IEC 62053-23
half-plane delivery half-plane consumption
Quadrant II Quadrant I
Quadrant III Quadrant IV
Q+
P-
P+
Q-
U
E
S
QC/P- EQL/P+
E QL/P- E QC/P+
E P- E P+

Měřící Energetické Aparáty
8
e display of the instrument MEg40+ shows total registers for the three-phase outlet.
e set of six registers for the individual phases are read by the user program. e phase
energy measurement is unimportant when it is measured in compensated MV networks
(MVL). Also in the recorder mode, only basic voltage, current, active power and voltage
event data and other user information appear on the display.
e basic measurement time is 10 periods. True RMS voltage, current, power and energy
values are measured continuously thanks to the phase lock look. As well, intervals to
record into the data memory are multiples of 10 periods. In this case, the sampling rate of
the measured voltages and currents is controlled by the phase locked loop derived from
the L1 phase voltage. e phase locked loop is active in the frequency range from 47.4 Hz
to 52.9 Hz. If the frequency of the L1 phase voltage is outside the frequency interval, the
sampling rate is set at 50.00 Hz.
Apparent powers, reactive powers and true power factors - PFs are calculated in MEg40+
from true RMS voltages and currents and from active powers recorded during the
recording interval into the Flash data memory. e reactive power includes a deformation
power component. e universal energy meter MEg40+ is designed for system, long-
term measurements. For this use, it has both usual synchronization of the internal time
through the oscillator frequency and synchronization of the internal time through the
network voltage frequency. is allows a unied analysis of events in the course and
also of long-term measurement campaigns. During a mains failure when internal time
synchronization through the network frequency is selected, the time is synchronized by
the internal oscillator with f = 50.00 Hz.
In the function of time course recording, the interval to record the measured values
can be set from 1.0 sec to 1 hour. Besides average values for the recording interval, it
is also possible to store maximum and minimum values of 0.2 sec (10 periods) in the
memory, which occurred in the recording interval. It is also possible to record RMS
values measured in the time when the recording interval is nished.
In order to protect the data memory from lling with clusters of numerous unimportant
events, e.g. in case of voltage oscillations near the specied limits, it is possible to record
events on a new page only after it is opened. It does not occur prior to the time dened
after the previous page is opened. It allows suppressing the possibility to ll the entire
data memory with unimportant data in case of clusters of events.
e standard size of the data memory of the instrument MEg40+ is 4 MB. When average
values of all voltages, currents, active and reactive powers, and energies in the summary
set of six registers, and up to 50 events per 27 hr 05 min are recorded, it is possible to store
data for the time period of 577.3 days in the 4 MB memory with the recording interval
of 10 minutes. When the 16 MB memory card is used and the recording is selected for
all average values of measured quantities, maximum and minimum voltages, maximum
currents and active powers, energies in the set of six registers in the individual phases in

9
Universal Energy Meter MEg40+
5-minute intervals and for up to 30 events during every 6 hr 45 min, the minimum time
of measurement is 573.6 days.
en both 10-minute voltage quality evaluations and 15-minute energy evaluations can
be made from 5-minute intervals.
e organisation of the internal data memory of MEg40+ and the memory card can be
circular or linear. When the measured data are stored into the circular data memory,
after the memory is full, the oldest data in the range of one page are deleted and new
data are recorded on their place. When the measured data are stored into the linear
data memory, after the memory is full, the new measured data are not recorded into
the memory and the data measured after the measurement is started are stored in the
memory permanently. Cooperation of the internal data memory and the memory card is
included in the following description of the 16 MB memory card.
An event is registered when the voltage Urms(1/2) of any phase gets out of the preset limits;
according to ČSN EN 50160, ed. 3 it is 90 % Unom and 110 % Unom. e beginning and
ending time of an event can be recorded with the max. inaccuracy 10 msec. During
an event, minimum and maximum voltages Urms(1/2) are evaluated, or also currents of
all phases. e event ends when all of the voltages return in accordance with ČSN
EN 50160 into the allowable tolerance band narrowed by the hysteresis of 2 % Unom. E.g.
if the limits of 90 % Unom and 110 % Unom are selected, then the limits to end an event are
92 % Unom and 108 % Unom. Beside the time when an event occurred, also the duration
of the event is recorded. As an event, it is also recorded a measurement failure due to
a supply voltage loss, and it is recorded the beginning and ending time of the failure.
e universal energy meter measures for 1 sec also in case of a supply voltage failure.
Duration of longer failures is measured using the internal backup clock with the time
resolution of 1 sec. After the failure ends and the supply voltage is restored, the HW of the
instrument MEg40+ is checked for about 1 sec and then the measurement is restored. e
duration, during which the measurement is interrupted in case of a longer power failure,
is extended by about 1 sec.
When it is required so that the instrument measures also during supply voltage failures,
see ČSN EN 61000-4-30, ed. 2, it is possible to order also the uninterruptible power
supply MEg102 together with the instrument MEg40+, which can supply the instrument
MEg40+ during up to four subsequent supply voltage failures always for the required time
of 3 minutes.
In the function of measurement and registration of maximum currents, the maximum
currents are searched in the instrument MEg40+ among values measured during the
preset measurement interval for each phase and the whole outlet from the beginning of
the measurement, which appear only on the display of the instrument together with the
time of occurrence.

Měřící Energetické Aparáty
10
e user software evaluates maximums for selected recording intervals on the individual
phases and also for the whole outlet for the recording interval and 1/4hr maximums.
Besides, daily diagrams of average currents are determined for any selected day.
e basic version of the instrument MEg40+ has a bidirectional serial communication
USB 2.0. When measurement is stopped and the communication speed increases
to 256 kbit/sec, the 4 MB data memory is read within 7 minutes. Measured data are
transmitted from the 16 MB memory card to PC using a memory card reader within
4 minutes. For remote communication, optional communication RS232 or RS485 is
available. e communication interface USB 2.0 can be converted to the interface RS485
additionally using the USBhost /RS485 converter.
e function of the user program MEg40+ is described in a separate user manual.
4/ DESCRIPTION OF CONTROLS AND DISPLAY
e front panel of the instrument MEg40+ includes a large-area graphic backlit display
with 64 × 128 pixels and four environment-resistant foil keys with mechanical response.
e function of the keys is preset by the control program of the instrument. ere is also
a connector of the serial interface USB 2.0 and a covered two-row connector of the 16 MB
memory card. e serial number of the instrument and prescribed data are specied on
the front panel.
e rear panel includes vents, two rows of terminal blocks with marked individual
terminals, rated current and rated voltage data and safety information.
After the supply voltage is applied and the HW function of the instrument is successfully
checked, basic data about the control program appear on the display temporarily. en
according to the settings made before the power supply was interrupted, rotating energy
registers of the function Energy meter or selected measured values of the function
Monitor are displayed. e display returns to the preset mode always automatically when
no of the instrument buttons is activated for 1 minute
e universal energy meter MEg40+ is set by the manufacturer so that after the power is
on, values of all energies of all of six registers for the whole outlet can rotate gradually on
the display from EP+ to EQC/P-. e energy values appear on the display in the format with
eight digits before the decimal point and three smaller decimal digits after the decimal
point. e type and unit of the measured energy is given above the energy value, and the
energy code is displayed under the energy value according to OBIS standard. To stop the
rotation of register values, use the left outside button Stop. You can browse through the
registers manually using the other two buttons with up and down arrows (↑ ↓). After
the required register is found, the value of the selected register appears on the display for

11
Universal Energy Meter MEg40+
1 minute. en the rotation of the registry values is restored. e rotation can be restored
using the button Start. When the button Menu is enabled, the item Energy meter and
the item Monitor appear. By turning to the item Energy meter (inverse display) and
pressing the button Select, you display the items Displ. interval, Cycle type and Higher
resolution. By selecting the item Displ. interval you can change the speed of rotation
of the displayed register values after 5 s, 10 s, 15 s, 20 s, 30 s, by selecting the item Cycle
type you can change rotation of all six registers for Consumption + delivery or only
three registers for Consumption or Delivery. By selecting the item Higher resolution
and yes, the frozen register values appear for 1 minute with 1 000 times higher resolution,
which results also in changes of displayed units. e default resolution is always basic, not
increased. In case of the higher resolution, three highest orders are cut o.
After the item Monitor is enabled, the items Measuring instrument, Maximum
currents, Recorder and Check of wiring are displayed and the buttons have assigned
the meanings End, ↑ - setting one line up, ↓ - setting one line down and Selection. Press
the button End to complete the preset selection and return the program to the previous
selection, i.e. in this case to the display mode of the function Monitor. Press the buttons
↑ or ↓ to set the corresponding inversely displayed line and press the button Select to
select the item on the set line.
After the main item Measuring instrument is selected, the following four items
appear on the display: View parameters, Voltage measurement parameters, Current
measurement parameters and Instrument parameters.
By selecting the item Display parameters you can display the items Type, Interval
and Method. After selecting the item Type you can use the buttons ↑ and ↓ to select
the display by quantities, by phases or simultaneous display of all outlet quantities. e
selected display type is to be conrmed by pressing the button End.
When displaying the item Quantity and returning to the basic display, you can use the
button U to continuously display phase or delta values, or the button I to display phase
currents, and the button P to display phase active powers. When measuring in a MV
network with a compensation coil MVL (vnL), the outlet power marked ∑P is displayed
instead of phase powers.
By simultaneous pressing more buttons, you display the selected quantities alternately
with the preset time of display.
When the item Phase is selected, use the dark button of the selected phase to display
the voltage, current and active power. According to the pre-selection, phase and delta
voltages, phase currents and active powers of the selected phases are displayed. As well in
this case, by simultaneous pressing more buttons you can display corresponding phases
alternately.

Měřící Energetické Aparáty
12
When the item Outlet is selected, all three voltages, three currents and three phases or
active powers are displayed simultaneously, or the total active power of the outlet.
By selecting the item Interval you can select the repeat interval to display new values
in seven steps from 0.2 sec to 12.8 sec. By selecting the item Method, you can select the
display in absolute units or in % of the rated value.
After you select the items Voltage measurement parameters and Current measurement
parameters for the rst time, the item Password appears to prevent from unauthorized
intervention into the setting or displaying of parameters of the voltage and current
measuring chain.
e password is four-digit and is set in the form of 3355. Each of the password digits can
be selected separately using the buttons ↑ and ↓ and is conrmed by the button Select.
After entering all of the four password digits, complete the entry by pressing the button
End. e password can be changed and read by the PC program. Even if the password
is not entered correctly, you can browse parameters of the current and voltage chain but
possible changes are not realized after you press the button Select.
By selecting the item Voltage measurement parameters, you display the items Level,
Voltage and Unom. To select the line with the required item, use the buttons ↑ and ↓.
After selecting the item Level you can use the buttons ↑ and ↓ to set the LV, MV, MVL
and HV level. After you press the button Level selection, the instrument made for the
rated voltage 57.7 V will accept MV, MVL or HV levels and the instrument made for the
rated voltage of 230 V will accept only the LV level. By selecting the item Voltage you can
set and select the display of phase or delta voltages. By selecting the item Unom you can set
only the value of 230 V for the LV level, delta voltages of 3 kV, 6 kV, 10 kV, 20 kVA, 22 kV
and 35 kV for the MV level and delta voltages of 110 kV, 220 kV and 400 kV for the HV
level. e non-standard MV voltage 20 kV can be substituted by any other non-standard
real value by changing the program.
By selecting the item Current measurement parameters you display the items Iprim
and Isec. In the item Iprim you can set one of the standard values of primary currents
of the measuring current transformers: 1 A, 5 A, 10 A, 12,5 A, 15 A, 20 A, 25 A, 30 A,
40 A, 50 A, 60 A, 75 A, 100 A, 125 A, 150 A, 200 A, 250 A, 300 A, 400 A, 500 A, 600 A,
750 A, 1000 A, 1250 A, 1500 A, 2000 A, 2500 A. You can also set a non-standard value
of the primary current of the current transformer User. e item Isec displays the size of
secondary input of the measuring current transformer, for which input current circuits
of MEg40+ are prepared. e default values are 1 A or 5 A. When a measuring current
split core transformer PTD is used and current inputs of the instrument MEg40+/S1 are
connected in the corresponding way, the character S1 is displayed. e designation S3 is
for the use of exible sensors AMOSm. When S1 is selected, rated primary currents of
transformers PTD can be set at 100 A, 200 A, 300 A, 400 A, 500 A, 600 A a900 A. When
S3 is selected, rated primary currents of sensors AMOSm can be set at 250 A, 500 A,
1000 A a 2000 A.

13
Universal Energy Meter MEg40+
When you select the item Instrument parameters, the instrument MEg40+ displays
the basic information about the instrument, i.e. serial number, control program version
- FW, date and time of the internal clock and capacity of the Flash data memory of
the instrument. When the 16 MB memory card is inserted, the capacity of this card is
displayed. To return to the previous selection, use the button End.
When you set and select the main item Maximum currents, the instrument MEg40+
displays maximum currents for the measurement interval for each phase and maximum
value of the sum of phase currents measured by the instrument from the programmed
start. As well times and dates are displayed, when the individual maximums occurred.
After the item Recorder is selected, information about the course of function is displayed.
When the record is not active, the message Record completed will appear on the line
Status or the message Recording when the function Recorder is set. When the function
Recorder is programmed, also additional lines appear on the display including the
recording start time, i.e. hour, minute, second and date, and information that measured
data are stored in the memory, i.e. linear or circular memory, including information
about the interval when the measured data are stored into the memory.
After you select the item Check of wiring, four functions run automatically to check the
wiring of connected measuring circuits for correctness. ey are the following functions:
• voltage connection check,
• phase sequence check,
• current connection check,
• phase assignment check..
e used checking procedure may not detect double and multiple errors in the wiring
and may not be eective even when the wiring is correct, if there is a big voltage or
current unbalance or power factors and currents are small. e correct result of the
checking function is indicated by OK. In case of an ambiguous result, the quantities will
be displayed, because of which it was impossible to decide about the correct wiring, and
after the button TEST is enabled, the result is marked with the question mark. A wiring
error is indicated by the word Error.
To check voltage connections, phase and delta voltages are checked. is function
assumes phase voltages higher than 0.75 Unom. If it is found out that one, two or all
three voltages are not connected, the message „Voltage connection error“ will be displayed
and the evaluated delta voltages, from which the disconnected voltage can be derived. e
Voltage connection checking function may not be eective to check the common wire
for connection.
e following function checks the phase sequence. e check result is the message Phase
sequence 123 (clockwise) or Phase sequence 132 (counter-clockwise).

Měřící Energetické Aparáty
14
e Current connection function checks currents for correct ow through individual
circuits of the instrument MEg40+ and for correct direction, which must be in phase with
the voltage corresponding to the voltage input. e allowable phase shift is ± 80°. If no
current ows through the current input or its direction is turned relative to the voltage,
then the message Current connection error and active powers of the individual phases
will be displayed. According to the sign and size of the active power, you can determine
the error in the connection of the corresponding current. is function assumes a phase
current more than 3 % Inom at the rated voltage.
e last function checks voltages and currents of the individual phases for correct
assignment. If the voltage and current assignment is incorrect, the message Current
assignment error and phase shifts between U1-I1, U2-I2 and U3-I3 will be displayed.
e phase shifts in the realized wiring are expressed in degrees. is check is eective
when the power factor is higher than 0.65.
5/ INSTALLATION
e universal energy meter MEg40+ shall be installed into a square hole of the panel
with the dimensions of 92 × 92 mm ± 1 mm to ensure access from both sides to the screw-
on terminals and a free space above and below the instrument to remove heat from the
instrument and install eccentrics, which attach the instrument to the panel mechanically.
White eccentrics are to be inserted into proled holes in the top and bottom of the black
housing of the instrument and turned towards the panel. To take out the eccentrics when
disassembling the instrument, turn the eccentrics backwards and remove from the holes.
e voltage inputs of the instrument MEg40+ meet requirements of the measurement
category IV according to ČSN EN 61010-2-30 and can be connected directly to LV
collectors of the transformer station. In cases where the station includes a voltage circuit
protection or in cases where it is expected that voltage circuit protection will be realized
for other measuring instruments, the manufacturer recommends you to connect also
voltage inputs of the instrument MEg40+ to the protected circuits. e measured voltages
U1, U2 and U3 in LV networks are to be connected through xed or exible wires with
the minimum cross-section of 0.75 mm2 with double insulation.
Also in MV networks with resistance and compensated networks (MVL) and HV
networks, indirectly measured voltages U1, U2 and U3 are always connected to the phase
conductors and the measuring instrument measures phase or delta voltages according to
the programmed requirement. To the terminal Nm in MV, MVL and HV networks, the
ground is always applied. In LW networks, the central conductor is to be connected to
the terminal Nm.

15
Universal Energy Meter MEg40+
Current inputs of the instrument MEg40+ shall be always connected indirectly to
secondary circuits of the measuring current transformers through xed or exible wires
with the cross-section of 3 mm2 with double insulation. It is recommended to connect
them through a terminal block with the possibility to short-circuit secondary currents
of the measuring current transformers. e secondary current of the measuring current
transformer of the phase L1 is brought to the input terminal I1K of the instrument
MEg40+ and goes out from its output terminal I1L. e secondary current of the
measuring current transformer of the phase L2 is brought to the input terminal I2K
of the instrument MEg40+ and goes out from its output terminal I2L. e secondary
current of the measuring current transformer of the phase L3 is brought to the input
terminal I3K of the instrument MEg40+ and goes out from its output terminal I3L.
e current circuits inside the instrument MEg40+ are not galvanically connected, the
maximum allowable voltage between the current circuits is 50 V.
When it is measured in LV and MV networks, where measuring current transformers are
not installed, measuring split core instrument transformers PTD can be used to measure
currents - made according to the pat. No. 286255, with the rated current from 100 A to
900 A and a window size of 68 × 68 mm. en the universal energy meter is in the version
MEg40+/S1.
When it is measured in a LV network, the voltage of 230 V is not allowed to be connected
to the current terminals of the instrument in the version MEg40+. Direct current
measurement is impossible.
e supply network voltage 230 V / 50 Hz or uninterruptible voltage 230 V / 50 Hz is
applied to the terminals Network 230 V of the instrument; the position of the phase and
central conductor is unimportant. It is also recommended to install a protection element.
After all of the measuring and supply circuits are connected, it is possible to check them
for correct connection by activating the function Check of wiring, which is described in
the previous chapter.
e instrument MEg40+ can be delivered with the inserted 16 MB memory card. In
this case, it is not allowed to take out or handle the memory card during installation.
erefore the card is covered with a sticker by the manufacturer, which shall be removed
after the measurements are programmed. If the instrument MEg40+ is not delivered
with the memory card, the card slot is covered with a plastic cover. e memory card is
described in a separate chapter.
Warning!
When the instrument MEg40+ is used in a dierent way than it is specied
by the manufacturer, the protection provided by the instrument MEg40+ can
be impaired.

Měřící Energetické Aparáty
16
5.1 Installation of the instrument with the serial communication
RS485, RS232
e universal energy meter MEg40+ can be installed also into networks with commu-
nication interface RS485 or RS232. e required communication interfaces must be
specied in the order.
e modulation rate of the communication interfaces RS485 and RS232 is 115.2 kBd.
No data transfer is possible at an increased rate with interruption of the measurement.
To interconnect, it is recommended to use a shielded twisted pair. e connection of
terminals for RS485 and RS232 communication is as follows:
INSTRUMENT MEg40+
(direction from the instrument)
INTERFACE
RS485
INTERFACE
RS232
TxD (output) Rx+ or RxTx+ TxD
RxD (input) Rx− or RxTx− RxD
⊥shielding ⊥
If it is necessary to additionally ensure remote communication with the instrument
MEg40+ equipped with the USB 2.0 interface, it is possible to use the USBhost / RS485
converter to convert the USB 2.0 interface to the RS485 interface.
6/ OPERATION OF THE INSTRUMENT MEG40+
Operation of the instrument MEg40+ in the basic version includes programming the
measurement, reading the measured data of USB 2.0 communications, and taking out
the memory card with measured data and inserting an empty card if 16 MB memory
card is used.
e measurement is programmed in the instrument MEg40+ using PC or PDA with the
running user program MEg40+ when the PC or PDA are connected to the instrument
MEg40+ through the communication cable MEg40+-PC, 1.8 m or 5 m long, with ferrite
absorbers. e procedure how to program measurements is included in the description of
the program MEg40+. After the function Recorder is programmed, the letter Z appears
permanently in the top R.H. corner, and after the function Registration of events is
programmed, the letter U appears permanently in the top R.H. corner of the display of
the instrument MEg40+.
It is possible to read the measured data through the serial communication USB 2.0 without
interrupting the measurement when the data are read into a data le in PC at the speed
of 115.2 kbit/sec. e measured data can be read into the data le also with interruption
of the running measurement, then the communication speed increases automatically to
256 kbit/sec and the communication is not interrupted due to the running measurement.

17
Universal Energy Meter MEg40+
us, the data reading time can be signicantly reduced, however the new measured data
will be saved into a new data le after the data transfer is completed.
After communication is nished with interruption of measurement, the new
measurement must be programmed. rough the serial communication, the measured
data can be read both from the internal data memory (4 MB) and from the 16 MB
memory card.
However, the data transfer from the 16 MB memory card is more ecient, when the
16 MB memory card is taken out from the instrument MEg40+ and inserted into the
memory card reader connected to PC with the active reader control program. en the
data are read at the speed of 921.6 kbit/sec and the full card is read out within 4 minutes.
During one reading, you can read gradually up to eight memory cards. e operator
does not need PC to take out the 16 MB memory card with the measured data from the
instrument MEg40+ and insert the new empty 16 MB memory card into the instrument
MEg40+. en the operator hands on the 16 MB memory cards with the measured data
for reading and deleting. A detailed description of the data reading from the 16 MB
memory card is given in a separate chapter of this manual.
7/ MAINTENANCE INSTRUCTIONS
e universal energy meter MEg40+ does not include any movable parts, and therefore
it does not require any mechanical maintenance other than common cleaning of the
panel. To clean, you can only use soft materials and non-aggressive solutions, preferably
water with a detergent. It is necessary to ensure that the vents in the rear panel of the
instruments are open through.
In demanding climatic and operating conditions, the manufacturer recommends you
to check the accuracy of measurements in the interval from 4 to 8 years of operation,
depending on the importance of the place of measurement. Accuracy of measurement is
checked using a multimeter with accuracy of voltage and current measurement at least
one class higher than the accuracy of the instrument MEg40+. e manufacturer of
the instrument MEg40+ recommends e.g. multimeter Agilent 34401A. If you detect an
error bigger than corresponding to the specication of the instrument, MEg40+ must be
recalibrated. You can order the measurement accuracy check and calibration also at the
manufacturer of the instrument MEg40+.
8/ CONTENTS OF THE SET
e set of the universal energy meter MEg40+ includes:
• 1 instrument MEg40+,
• 2 eccentrics,

Měřící Energetické Aparáty
18
• certicate of guarantee and delivery note,
• CD with the basic user program and manual..
Optional available accessories:
• communication cable MEg40+-PC / 1.8 m or 5 m,
• 16 MB memory card,
• reader of 8 memory cards,
• uninterruptible power supply MEg102,
• USBhost / RS485 converter with cable long 1 m.
e following versions are available for ordering beside the version MEg40+ with
USB 2.0 interface:
• version MEg40+ with interface RS485,
• version MEg40+ with interface RS232.
9/ DELIVERY
e place of delivery unless otherwise specied is the seat of the manufacturer. e set
of the instrument MEg40+ is delivered in the multilayer cardboard box with a delivery
note and a certicate of guarantee. e serial number of the instrument MEg40+ packed
inside, its measuring ranges and list of delivered accessories are specied on the packaging.
For transport, it is necessary to protect the front panel of the instrument with the display
and inserted memory card against mechanical damage using a multilayer cardboard
insert.
10/ GUARANTEE
Two-year standard guarantee is provided for the universal energy meter MEg40+ and its
accessories from the date of its sale. Defects incurred during this period due to provably
defective construction, defective design or improper materials will be repaired free of
charge by the manufacturer; the place of performance of the guarantee is the seat of the
manufacturer of the instrument MEg40+.
e guarantee becomes invalid if the user carries out unauthorized modications
or changes on the instrument MEg40+ or its accessories, or connects the instrument
incorrectly, mechanical wearing of the instrument is inadequate or the instrument
MEg40+ or its accessories was operated contrary to the technical specication.

19
Universal Energy Meter MEg40+
Defects of the instrument MEg40+ and its accessories incurred during the guarantee
period shall be claimed by the user to the manufacturers of the instrument MEg40+.
Claims without the enclosed certicate of guarantee shall not be admitted.
e manufacturer shall not bear any responsibility for consequential damages caused
by the use of the instrument MEg40+ and its accessories. No responsibility of the
manufacturer follows from this guarantee that would exceed the price of the instrument
MEg40+.
11/ ORDERING
e order should indicate a number of pieces of the universal instruments MEg40+ with
one of the possible parameters:
• voltage range: 57.73 V, 230 V,
• current range: 1 A, 5 A,
• serial communication type: USB 2.0, RS485, RS232
You can order only one type of the serial communication.
Specify extra:
• requirement for memory CARD 16 MB
• requirement for extended SW,
• number of memory card readers,
• number and length of communication cables MEg40+-PC
• number of uninterruptible power supplies MEg102,
• number of USBhost / RS485 converters.
Note
In the order, you can dene the voltage level, rated primary voltages and currents or
wiring type in the place of installation of the instrument. e manufacturer will program
these data into the instruments before dispatching them. e given data can also be
programmed by the orderer during installation of the instrument. You can order also a
four-digit password dierent from the password dened by the manufacturer. (3355). e
password can be changed after installation of the instrument either by means of software
or from the keyboard. A changed or forgotten password can be read out only using the
user program MEg40+.
12/ MANUFACTURER
MEgA – Měřící Energetické Aparáty, a.s., 664 31 Česká 390, Czech Republic,
tel: [phone] • mail: [e-mail] • web: http://www.e-mega.cz

Měřící Energetické Aparáty
20
L1
L2
L3
N
I2K
I2L
I3K
I3L
I1K
I1L
U1
U2
U3
Nm
SIŤ
MEg40
MTP
MTP
MTP type MBS ASK 51.4
230V,5A/1A
connection terminal WKS 1/2
type WTL 6/3 STB type WTL 6/3 STB
OPV 10/3
PV 10 6A gG
SIŤ
+
SISISISI SISI SUSU SUSU SISI SUSU SUSU SISISISI
Fig. 2: Wiring of the instrument MEg40+ in LV network without uninterruptible power
supply
Fig. 3: Wiring of the instrument MEg40+ in a LV network with uninterruptible power
supply
MTP
MTP
MTP type MBS ASK 51.4
OPV 10/3
PV 10 6A gG
connection terminal WKS 1/2
type WTL 6/3 STB
L1
L2
L3
N
type WTL 6/3 STB
uninterruptible power supply
230V, 50Hz, 8VA
230V,5A/1A
SIŤ
I2K
I2L
I3K
I3L
I1K
I1L
U1
U2
U3
Nm
SIŤ
MEg40+
SUSU
SISISISISISISISISISISISI SUSUSUSUSUSUSUSU
PE
PE