Victron Energy EM540 Energy Meter Manual

1. Introduction

The Victron EM540 is a standard device used to measure the power and energy of a 3-phase application. It can be used, for example, at the distribution box or to measure the output of a PV inverter, AC Genset, or an inverter/charger. The data is displayed on a GX device and the VRM portal.

1.1. Features

The EM540 can be configured for four different roles in a GX device, such as the Cerbo GX:

• As a Grid meter and used as control input for an ESS System.
• To measure the output of a PV Inverter.
• To measure the output of an AC Genset.
• As an AC meter to measure the output of an inverter or inverter/charger.

It offers two options for connection to a GX device:

1. A wired connection using the RS485 to USB interface with a 1.8m or 5m cable length.
2. A wireless connection via the Zigbee to USB and Zigbee to RS485 converter.

2. Installation and Configuration

2.1. AC Wiring

The configuration option (Grid Meter, PV Inverter, Generator, or AC Meter) is set in the GX device. Refer to the GX device configuration chapter for details. This selection affects how the system is wired and how the information from the meter is displayed.

2.1.1. Configuration Options

See the diagrams below for different wiring options.

2.1.2. System Examples

Diagram 1: EM540 wired as a 3-phase Grid meter

This diagram shows a 3-phase connection with an EM540 meter, a fuse, and three Victron MultiPlus units, connected to a grid.

Diagram 2: EM540 wired to measure a 3-phase PV Inverter

This diagram illustrates an EM540 meter connected to a 3-phase PV inverter. Terminals 1, 2, and 3 of the EM540 face the PV inverter to ensure correct current and power direction.

Diagram 3: EM540 wired as a single-phase, single-function PV inverter meter

This diagram shows a single-phase EM540 meter measuring a 1-phase PV inverter within a 3-phase system. The PV inverter can connect to any of the three phases.

Diagram 4: EM540 wired as a single-phase, single-function Grid meter

This diagram depicts a single-phase EM540 meter used as a grid meter.

Diagram 5: EM540 wired as a single-phase, dual-function Grid meter also metering a PV Inverter on L2

This diagram shows a single-phase, dual-function setup where the EM540 acts as a grid meter and also meters a PV inverter on L2.

Single-phase, single function

• To measure a single-phase PV inverter in a 3-phase system, connect all 3 phases to the grid phasing terminals (4, 5, and 6). Connect the PV Inverter by wiring its L1 line to the desired phase (L1, L2, or L3 - terminal 1, 2, or 3).
• To measure the grid in a single-phase system, connect the grid to L1 (terminal 1) of the EM540.

Single-phase, dual function

For a three-phase meter in a single-phase installation measuring the grid on one input and the PV inverter output on another, ensure the energy meter uses L1 and the PV inverter uses L2. Refer to the GX device configuration chapter for setup details.

2.2. Connection to a GX device

2.2.1. Wired connection to a GX device

Connect the EM540 to the GX device using the RS485 to USB interface. The EM540 is plug-and-play, with pre-configured RS485 settings. The RS485 to USB interface cable can be extended up to 100 meters. Ensure extensions of Data+ (orange) and Data- (yellow) wires are twisted pairs.

Wiring Table:

The red, green, and brown wires from the RS485 to USB cable are not used; cut or fold them back and isolate them.

Diagram 6: EM540 wired connection to a Cerbo GX using the RS485 to USB interface

This diagram shows the EM540 connected to a Cerbo GX via an RS485 to USB interface, illustrating the wiring for data and ground connections.

Important considerations for signal integrity:

• Ensure extension cabling meets minimum cross-sectional area specifications.
• Use cabling with appropriate shielding and twisted pair cores.
• For installations exceeding 10m or with site-specific interference, reduce the original Victron RS485 USB interface cable length to a maximum of 20cm and use a suitable cable for the remaining length.
• Install cabling away from main DC or AC power cabling.
• Ensure all wiring is properly terminated, unused wires are isolated, and protected from weather/water ingress.
• RS485 networks typically use 120Ω terminators at both ends. This may not be necessary for short cable lengths with Victron's supplied cables but might be required if the cable length is modified.
• Refer to the Victron RS485 to USB interface cable 'Datasheet' for detailed wiring and installation notes.

2.2.2. Zigbee connection to a GX device

The EM540 can be wirelessly connected to a GX device using a Zigbee to USB converter and a Zigbee to RS485 converter. The Zigbee to USB converter connects to the GX device, and the Zigbee to RS485 converter connects to the EM540.

1. Connect the Zigbee to USB converter to the GX device using the supplied USB cable. The active LED should turn on, and the TX/RX LED should blink after a few seconds. The converter draws power from the GX device, so ensure the GX device is powered on.
2. Connect the Zigbee to RS485 converter to the EM540 energy meter according to the table below:

If multiple Zigbee devices are installed, power up only one Zigbee device at a time (the Zigbee to USB converter connected to the GX device). Power down all others to prevent permanent connection to another Zigbee device.

3. Connect the 12V DC power supply to the Zigbee to RS485 converter. Check the LEDs after powering on.

Diagram 7: Energy Meter wireless Zigbee connection to a Cerbo GX

This diagram illustrates the wireless connection of an EM540 energy meter to a Cerbo GX using Zigbee converters.

Note on old and new Zigbee converters: A new Zigbee converter is available that is not backward compatible with older versions. Refer to the table for part number differences. Contact your supplier for compatible versions if you have a non-compatible set.

Note on GX firmware versions: For the new Zigbee converters, Venus OS v2.54 is the minimum required software version.

2.3. GX device configuration

After connecting and powering up, the meter(s) will appear in the GX device's Settings → Energy meters menu.

Image 1: Single Energy Meter in the Energy meters menu

Image 2: Two Energy Meters in the Energy meters menu

After selecting an Energy Meter, set the Role and Phase type. Press the space bar or right-click to access the Phase type and Role menu.

Image 3: Setting Role and Phase type for an AC meter (Single phase)

Image 4: Setting Role and Phase type for a Grid meter (Multi phase)

Select the Role or Phase type and press the space bar to make changes.

Image 5: Role selection menu

Image 6: Phase type selection menu

Single-phase, single function and single-phase, dual function mode setup:

Image 7: Single-phase, single function setup

Image 8: Single-phase, dual function setup to measure grid on L1 and PV inverter on L2

After settings are applied, the Energy Meter data appears in the GX device's device list.

Image 9: Device list showing various Victron devices and energy readings

Image 10: Energy meter measuring AC loads on the AC output of the inverter/charger

Image 11: Energy meter configured to measure grid consumption

Right-click or press the spacebar to access the Energy Meter overview with detailed energy consumption and generation data. The role can be set via the Setup menu, and communication data can be read via the Device menu. A custom name for the Energy Meter can also be set.

Image 12: Detailed overview page of a 3-phase Grid meter

Image 13: Device menu showing connection details and product information

Image 14: Setup menu for quickly changing roles

2.4. Multiple Energy Meters in one system

To connect multiple Energy Meters, wire each meter to a separate RS485 to USB interface, then plug them into separate USB sockets on the GX device.

There are 3 options to connect multiple Energy Meters:

• Each wired to a separate RS485 to USB interface, plugged into a separate USB socket on the GX device.
• Two Energy Meters wired to one RS485 to USB interface. The Modbus address of the additional meter must be changed to be unique. See the next chapter, 'Changing the Modbus Address'.
• Wireless connection: The additional meter connects to an additional Zigbee to RS485 converter. A second Zigbee to USB converter is not required. The Modbus address of one of the AC sensors must be changed. See the 'Changing the Modbus Address' chapter.

In a single-phase installation, an unused second phase can be used to measure the PV inverter's power. Refer to the 'AC Wiring' chapter.

2.4.1. Changing the Modbus Address

Follow these steps to change the Modbus address:

1. Press the small button on the EM540 to enter the 'Setting' page.
2. Briefly press the small key again to enter the 'System' menu.
3. Press the down key until the 'RS485' menu is displayed.
4. In the 'RS485' menu, press the small button to enter the 'Address' menu.
5. Use the up or down button to change the address to 2 for the additional EM540.
6. Press the small button repeatedly until 'RS485' is displayed again.
7. Scroll through the menus using the down button until 'End' is shown.
8. Press the small button to return to the 'Setting' page.
9. Press the left button. It should now display 'back'.
10. Press the small button to return to the overview page.

Note: Only one extra Energy Meter can be added. The system works with addresses 1 (default) and 2.

3. Information on Multiple Zigbee Pairs

3.1. Multiple Zigbee Pairs

Running multiple Zigbee pairs is unusual and not recommended due to configuration complexity with the Chinese language software. However, for those who wish to proceed, here is a possible solution.

The following applies only to the new Zigbee converters (DRF2658 and DRF2659). Older units have no software support.

To run multiple pairs, the PAN-ID must be different to avoid interference. Basic information on obtaining software and reconfiguration:

1. Visit http://www.dtkcn.com/.
2. Use your browser's translation feature if you do not read Chinese, then download the "DTK wireless module configuration software".
3. The installation is in Chinese but can be completed by repeatedly clicking the "Next" button. The software itself has an English translation.
4. Wire an RS485 to USB interface to the RS485 Zigbee module for reconfiguration. Alternatively, reconfigure the USB unit (coordinator) BEFORE turning on the RS485 side (router). The router will join the coordinator and get its initial settings at startup.
5. Each pair must have a different PAN-Id.

It is unusual to have multiple Zigbee links. Using an Energy meter via Ethernet (possibly with a Wi-Fi link) is a more reliable option in any case.

4. FAQ

Q1: Can I combine three ET112s for a 3-phase system?

No. Use a dedicated 3-phase meter.

Q2: Can I use other meters, for example from other brands?

No.

Q3: I already have a Fronius SmartGrid meter, can I use that?

No.

Q4: What are the differences between the various 3-phase meters?

• EM540 - REL200100100 - Carlo Gavazzi EM540DINAV23XS1X
• ET112 - REL300100000 - Carlo Gavazzi ET112-DIN.AV01.X.S1.X
• ET340 - REL300300000 - Carlo Gavazzi ET340-DIN.AV23.X.S1.X

Differences:

• The ET meters have no display, only an LED that blinks during active communication.
• The ET meters have two RJ45 sockets, which are not used with the Victron RS485 to USB interface. Note the potential confusion with other Victron RJ45 sockets (VE.Bus, VE.Can, VE.net). The meters also have screw terminals below the sockets for RS485 wiring, which is the recommended connection method to the RS485 to USB interface and then to a GX device.
• Without a display, the Modbus address cannot be changed on the meter. Therefore, Victron does not support combining multiple ET meters on one RS485 network. Using multiple RS485 to USB interfaces is advised.
• For 3-phase meters only: Measuring energy from a single-phase PV inverter on the second phase of a 3-phase meter is functional.

Q5: Will you keep shipping both 3-phase meters? (ET340 & EM540)

Yes. Both have suitable applications. See Q8.

Q6: Can I buy those meters directly from Carlo Gavazzi instead of from you?

Yes. Victron Energy provides the Carlo Gavazzi part numbers for this reason.

Q7: I want to use Current Transformers (CTs), is that possible?

Yes. You can purchase a CG EM24DINAV53DISX or a CG EM530DINAV53XS1X directly from Carlo Gavazzi or their distributors. Victron Energy supports these meters in its software, although they are not stocked.

Q8: What's the difference between ET340 and EM540 in 3-phase systems?

The meters differ in how they calculate total imported and exported energy:

• ET340: Calculates energy imported and exported per phase, then sums these values for the total.
• EM540: Calculates total power, with net differential readings from each phase cancelling each other out.

The most suitable meter depends on your country's billing configuration. For example, in Austria and Germany, billing is often based on the total in a 3-phase system. The EM540 is more accurate for matching this billing method. If you export from one phase and import from another, before the billing meter, this will not be charged, and the EM540 will not count it as separate import/export. This aligns with Victron's phase compensation feature for ESS systems, maximizing cost savings when generation and load differ across phases.

Q9: Can I use an isolated USB-RS485 interface?

Yes. Victron Energy sells non-isolated interfaces suitable for most cases. For an isolated interface, purchase from Hjelmslund Electronics (USB485-STIXL: Isolated USB to RS485 converter).

Q10: Can I use Victron Energy Meters instead of a Victron Inverter/Charger to make use of a GX device (e.g. Cerbo GX), VRM and other features?

Energy Meters supplement Victron Inverter/Chargers. Their current applications are limited to providing specific information such as total loads on AC input, grid import/export, or AC PV inverter and AC generator production without network communications.

Initially, a GX device with an Energy Meter can be used to determine and record consumption (e.g., for houses, heating systems, or production facilities). This data helps in dimensioning the required Victron inverter/charger(s), solar system, and batteries. With GX device firmware version 2.80 and later, they can measure specific AC loads or circuits. However, this is not a replacement for a Victron Inverter/Charger. Attempting to use third-party battery inverters and substituting their lack of data connectivity with Energy Meters will not yield expected results.