Electric energy 29.02.2020 11:49 04.03.2020 17:44

We recommend the ED 310.DR (order number ED 310.DR.14E304-00) with direct measurement up to 60 A for the measurement of secondary generation (supply) and consumption of 3ph electrical energy.

The electricity meter can measure: the consumption and supply of active energy in kWh for the rates T1 to T4, RMS current, RMS voltage, instantaneous power, maximum current, maximum power, the power factor, the number of outages of voltage and information on the statuses: the active tariff (in which the electricity meter reads the consumption or supply) and the actual direction of the current (consumption/supply). All data can be read from the electricity meter using the TXN 149 01 optical probe, or the RS-485 communication line.

The following figure (on the next page) shows the connection of electricity meter ED 310.DR to the CH2 communication channel of the Foxtrot basic module. The next part of the chapter contains detailed information on the actual electricity meter.


Notes (referring to the figure):

  1. The RS-485 communication interface is terminated on two RJ-45 connectors. Both RJ-45 connectors are equal (internally connected). The description of the connector signals is shown in the table.

  2. The RS485 interface is galvanically isolated from other parts of the meter (4kV/50Hz/60s) and it is therefore necessary to supply the communication part from an external source. The power is also terminated on the RJ-45 connector; the supply polarity is irrelevant. N.B.: The interface power supply is electrically connected with the RS-485 communication interface, so a separate power supply (24VDC) must be used, or a galvanically isolated interface on the side of the Foxtrot system.

  3. The wiring in the figure (with no bus termination on the meter side) can only utilize a cable between the Foxtrot CH2 and the meter, which is no longer than 2 meters (ideally less than 1 m). A standard patch cable (preferably shielded FTP, also unshielded UTP) can be used for the connection; one end of the cable should be inserted into the connector of the electricity meter, the second should be nipped off and the wires should be connected as illustrated (see the table for the description of the connector and colours of the wires in standard UTP/FTP cables).

  4. If you need a longer cable, then (on the side of the meter - if there are several, it should be the last one) a 120 Ω resistor must be connected between the signals Rx/TX+ and Rx/Tx-, as close as possible to the meter. The resistor can be connected e.g. to the nipped-off end of the UTP cable and inserted in the other connector on the electricity meter.

  5. The figure shows the termination of the S0 output (terminals 11 and 12).

  6. The selection of tariff - (there are up to four tariffs) - is controlled by the terminal 1 and 2 against terminal 3.



The layout of RS485 interface signals on the RJ-45 connectors.

Pin of the RJ-45 connector


The colours of wires in a standard UTP patch cable (acc. to T568B)


The power supply input (e.g. +24 V - the supply polarity is irrelevant); the power supply of the RS-485 interface circuits, the pins are internally connected.







Rx/Tx +



Rx/Tx -



The power supply input (e.g. 0V - the supply polarity is irrelevant); the power supply of the RS-485 interface circuits, the pins are internally connected.







When the FTP cable is used, the braid should be connected to the PE terminal PE in the control panel.


Fig. .1 An example of connecting the ED 310 k CH2 CP-10x6 (10x8) electricity meter

The properties and parameters of the electricity meter ED 310.DR

The ED 310 electricity meter is a three-phase static four-tariff meter of active energy, class A or B in accordance with the EN 50470-1 and 50470-3 standard, which is designed for direct (ED 310) and indirect (ED 310) connection.

The electricity meter measures and saves these basic values (and if necessary, displays them on the screen):

  • The consumption and supply for each of the four tariffs (i.e. 8 energy registers).

  • The reading time of consumption and supply for each register (i.e. 8 time registers).

  • Total sums registers for the total consumption time and total supply time.

  • Maximum current and maximum power.

  • Operating time, the number of network outages, time after resetting the maximum current and power.

  • Instantaneous effective voltage.

  • Instantaneous effective current

  • Instantaneous active power


The ED 310 electricity meters measure in the range from the inrush current up to 63 A (ED 310.I to 7.5 A) with a sufficient margin in accordance with the standard (the DC component and harmonics).

The ED 310 electricity meters are equipped with up to three external inputs for switching up to 4 tariffs. Switching tariffs is done by alternating voltage applied between the tariff meter terminals. Indication of the active tariff is displayed.

The electricity meter is equipped with the RS-485 interface. The interface is electrically isolated from the other parts of the meter (4 kV/50 Hz/60 sec), and it is therefore necessary to power the communication part by an external source.

When the RS-485 bus is active, the meter optical interface is automatically disconnected.


Basic parameters of the electricity meter ED 310.DR


direct four-wire

Own consumption (voltage circuits incl. power supply)

maximum 0.7 W, maximum 8 VA cap.

The current circuit internal consumption

maximum 0.01 VA

Inrush current Ist

less than 15 mA

Minimum current Imin

200 mA

Reference current Iref

5 or 10 A

Maximum current Imax

according to requirements from 40 A up to 60 A

Maximum range of the measured current

15 mA ÷ 63 A

Nominal voltage Un

230 VAC

The operating voltage range

0.75 Un ÷ 1.15 Un

Pulse output S0

class A acc. to ČSN EN 62053-31


The number of pulses

programmable from 0.15 to 10,000 imp./1kWh


Nominal supply voltage

24 VDC


Maximum supply voltage

30 VDC


Maximum current


The RS485 interface

galvanically isolated from the electricity meter and from the 230V grid


The range of the interface supply voltage

12 ÷ 24 VDC or 12 ÷ 18 VAC


Maximum consumption from the power source of supply voltage

50 mA

Operating temperature range

-25 ÷ 55 °C

Maximum cross-section of the connected wire - a string

25 mm2

Maximum cross-section of the connected wire - a wire

16 mm2

Minimum cross-section of the connected wire

x mm2

The terminal bolt head

M5, Phillips countersunk, size 2

The torque of screw terminals

2 ÷ 3 Nm

The module dimensions (width x height x depth)

107 x 91 x 72 mm (6M)